Computer based CAE FSI models for simulating the physical behavior of diapers, diaper materials, and/or diaper machines during diaper manufacturing processes

Computer based CAE FSI models for simulating the physical behavior of diapers, and/or diaper materials, and/or diaper machines during diaper manufacturing processes.

FIELD

In general, embodiments of the present disclosure relate to computer based models for disposable articles. In particular, embodiments of the present disclosure relate to computer based CAE FSI models for simulating the physical behavior of diapers, diaper materials, and/or diaper machines during diaper manufacturing processes.

BACKGROUND

Diaper machines can use diaper materials to manufacture diapers. During diaper manufacturing processes, the diaper materials can interact with the diaper machines and with surrounding air. It can be difficult to predict the physical behavior of the diaper materials as they interact with the diaper machines and with the surrounding air. As a result, it can be difficult to predict whether or not a particular diaper machine design can successfully process a particular configuration of a diaper or diaper materials.

SUMMARY

However, embodiments of the present disclosure can at least assist in predicting whether or not a particular diaper machine design can successfully process a particular configuration of a diaper or diaper materials. The present disclosure includes methods of simulating the physical behavior of one or more diapers and/or diaper materials interacting with diaper machines and moving through surrounding air. As a result, particular diaper machine designs and particular configurations of diapers and/or diaper materials can be evaluated and modified as computer based models before they are tested as real world things.

DETAILED DESCRIPTION

The present disclosure includes methods of simulating the physical behavior of one or more diapers and/or diaper materials interacting with diaper machines and moving through surrounding air. Embodiments of the present disclosure can at least assist in predicting whether or not a particular diaper machine design can successfully process a particular configuration of a diaper and/or diaper materials. As a result, particular diaper machine designs and particular configurations of diapers and/or diaper materials can be evaluated and modified as computer based models before they are tested as real world things.

Computer aided engineering (CAE) is a broad area of applied science in which technologists use software to develop computer based models of real world things. The models can be used to provide various information about the physical behavior of those real world things, under certain conditions and/or over particular periods of time. With CAE, the interactions of the computer based models are referred to as simulations. Sometimes the real world things are referred to as a problem and the computer based model is referred to as a solution.

There are several major categories of CAE. Finite element analysis (FEA) is a major category of CAE, in which models of mechanical components and/or assemblies are used to predict stress, strain and other mechanical behaviors. Computation fluid dynamics (CFD) is another major CAE category, in which models of fluids (e.g. liquids and/or gases) are used to predict pressure, flow, temperature, and other fluid and/or thermal properties. Still another major category of CAE is fluid structure interaction (FSI), which models the physical behavior of fluids in relation to solid objects. There are also a number of other categories of CAE.

Some aspects of CAE can also relate to various Computer Aided technologies, sometimes collectively referred to as CAx. CAx includes a number of technologies, such as Computer Aided Design (CAD), Computer Aided Manufacturing (CAM), and Knowledge Based Engineering (KBE).

Commercially available software can be used to conduct CAE. Abaqus, from SIMULIA in Providence, R.I., and LSDyna from Livermore Software Technology Corp. in Livermore, Calif., are examples of commercially available FEA software. Fluent, from ANSYS, Inc. in Canonsburg, Pa., and Flow3D, from Flow Science, Inc. in Santa Fe, N. Mex. are examples of commercially available CED software. LSDyna is also an example of FSI software. CAE software can be run on various computer hardware, such as a personal computer, a minicomputer, a cluster of computers, a mainframe. a supercomputer, or any other kind of machine on which program instructions can execute to perform CAE.

CAE software can be applied to a number of real world things, such as disposable articles. The term disposable articles includes diapers, feminine hygiene products, and other disposable articles.

A diaper can be referred to in various alternate ways. As examples, a diaper can sometimes be referred to as an absorbent article, absorbent briefs, an absorbent product, an absorbent item, an absorbent garment, an absorbent pant, an absorbent panty, an absorbent undergarment, absorbent underwear, a wearable absorbent article, a disposable absorbent article, a disposable wearable absorbent article, incontinence briefs, an incontinence garment, an incontinence napkin, incontinence pants, an incontinence product, an incontinence towel, an incontinence undergarment, a nappy, a napkin, a pant, pants, a disposable pant, disposable pants, a training pant, training pants, a pull-up, pull-ups, etc. A diaper can be configured for use by various human wearers, such as infants and incontinent persons. Throughout the present disclosure, the terms diaper and diapers are intended to refer to one or more of any of these and all other forms of a diaper, unless otherwise stated.

CAE software can also be applied to diaper materials. Throughout the present disclosure, the terms diaper material and diaper materials are intended to refer to one or more diapers in any state of formation, from one or more starting materials, to one or more partially formed diapers, to one or more individual, finished diapers, and one or more diapers in any state or states in between.

CAE can be used to design, simulate, and/or evaluate diaper materials, their structures and compositions, as well as their performance characteristics, such as swelling and deformation. CAE can also be used to design, simulate, and/or evaluate diaper features or products. As examples, CAE can be used to simulate the performance of various aspects of diaper products, such as fluid transport and storage, thermal and mechanical performance, fluid structure interactions, product packaging and dispensing, and gluing performance. CAE can also be used to simulate the fit of a diaper product on a wearer.

As additional examples, CAE can be used to design, simulate, and/or evaluate diaper machines and/or diaper manufacturing processes. CAE can be used to simulate mechanical aspects of diaper manufacturing processes related to cutting, material deformation, bonding, and material-product interactions. CFD can be used to simulate air flow in diaper machines as well as liquid flow and/or transport in diaper manufacturing processes. CAE can also be used to simulate and/or evaluate the feasibility of diaper manufacturing processes, the reliability of diaper machines, and potential quality issues with diaper materials.

FSI can be used to simulate and/or evaluate the transport of particles in air in diaper manufacturing processes. For example, FSI can be used to design, simulate, and/or evaluate diaper manufacturing processes in which one or more absorbent materials are conveyed through a diaper machine and added to a web of diaper materials.

FSI can also be used to simulate and/or evaluate the transport and/or deformation of sheet-like diaper materials as they interact with diaper machines and with air in diaper manufacturing processes. As an example, FSI can be used to simulate and/or evaluate a physical behavior of a web of diaper materials interacting with a diaper converting machine and moving through air, as described in connection with the embodiments ofFIGS. 1A-4B, and8. As another example, FSI can be used to simulate and/or evaluate a physical behavior of diaper trim materials interacting with a trim removal apparatus and moving through air, as described in connection with the embodiments ofFIGS. 5A-8.

CAE software can also be similarly applied to aspects of some other disposable articles, such as paper towels, bathroom tissues, facial tissues, wipes, and cleaning pads, etc.

FIG. 1Ais an outside plan view illustrating an exemplary diaper110laid out flat. The diaper110includes a chassis111, side edges114, end edges115, an absorbent core112, and ears113. The ears113include fasteners, so the diaper110is configured as a fastenable diaper. The diaper also has a lateral centerline121, a longitudinal centerline122, an overall length123, an overall width124, and fold lines116. During the diaper manufacturing process, laterally outboard portions of the diaper110can be folded inward along the fold lines116, as described in connection with the embodiment ofFIG. 1B.

FIG. 1Bis an outside plan view illustrating a folded version of the exemplary diaper110of the embodiment ofFIG. 1A. InFIG. 1B, laterally outboard portions of the diaper110are folded along the fold lines116onto an inside of the diaper110. The folded diaper110has folded edges117and a folded width125.

The exemplary diaper110is not intended to illustrate all details of a diaper. The exemplary diaper110is also not intended to limit embodiments of the present disclosure. Instead, the exemplary diaper110is intended to illustrate at least some of the diaper features on one kind of diaper, which can be incorporated into a computer based model of a portion of a continuous web of diaper materials, as described in the embodiment ofFIG. 2A.

FIG. 2Ais an outside plan view illustrating a computer based model230of a portion of a continuous web of diaper materials231, for use in a diaper manufacturing process. During the diaper manufacturing process, the portion of the continuous web of diaper materials231moves with a velocity227in a machine direction228. The portion of the continuous web of diaper materials231includes a sheet-like series of partially formed diapers232-1through232-N, where “N” is any positive integer. In the embodiment ofFIG. 2A, the web of diaper materials231includes four partially formed diapers.

The partially formed diapers232-1through232-N are connected together end-to-end. For clarity, separation lines233illustrate end edges to be formed downstream in the diaper manufacturing process. Each of the partially formed diapers232-1through232-N can be a partially formed version of the diaper110of the embodiment ofFIG. 1A. In the embodiment ofFIG. 2A, each of the partially formed diapers232-1through232-N includes a chassis, an absorbent core, and ears with fasteners.

The model230of the portion of the continuous web of diaper materials231includes a leading edge241, a middle portion244, and a trailing edge245. The leading edge241corresponds with an end edge of the diaper232-N. The trailing edge245corresponds with an end edge of the diaper232-1. The model230also includes tensions resulting from tensioning forces247applied to the leading edge241and the trailing edge245.

In various embodiments, a computer based model of diaper materials can include any number of partially formed diapers, including portions of diapers. For example, in a computer based model, a continuous web of diaper materials can include a leading edge and/or a trailing edge, which may not correspond with an end edge of a diaper. In some embodiments, a computer based model of diapers and/or diaper materials can include partially or completely formed diapers with any number of any features, such as waistbands, leg bands, leg cuffs, absorbent core assemblies, etc. A computer based model of a diaper and/or diaper materials can, in some embodiments, include any kind of diaper, such as a fastenable type diaper or a preformed pant-type diaper.

FIG. 2Bis a plan view illustrating the computer based model230of the portion of the continuous web of diaper materials231, of the embodiment ofFIG. 2A. The computer based model230is illustrated as broken, to illustrate further details. The portion of the continuous web of diaper materials231includes the sheet-like series of partially formed diapers232-1through232-N. During the diaper manufacturing process, the portion of the continuous web of diaper materials231moves with a velocity227in a machine direction228. The portion of the continuous web of diaper materials231also includes fold lines216and a longitudinal centerline222, which correspond with the folds lines and the longitudinal centerlines of each of the partially formed diapers232-1through232-N.

The model230of the portion of the continuous web of diaper materials231can be created by using FSI software. The model230can be created by putting in dimensions and material properties for the portion of the continuous web of diaper materials231, generating a mesh, defining boundary conditions for the model230, and defining interactions between parts of the diaper materials and other parts and/or models. By doing so, the computer based model230can be configured to accurately simulate the physical behavior of a real world continuous web of diaper materials.

The portion of the continuous web of diaper materials231can be configured with dimensions that are similar to or the same as dimensions of a real world continuous web of diaper materials. These dimensions can be determined by measuring real world samples of diaper materials, by using accepted values for known materials, and/or by estimation. Values for the length, width, thickness, and/or other dimensions of the chassis, core, ear, fastener and other parts of the partially formed diapers232-1through232-N can be put into FSI software.

Some or all of the portion of the continuous web of diaper materials231can be configured with material properties that are similar to or the same as material properties of a real world continuous web of diaper materials. These material properties can be determined by measuring real world samples of diaper materials, by using accepted values for known materials, and/or by estimation. Values for the tensile strength, bending behavior, density and/or other mechanical properties of the chassis, core, ear, fastener and other parts of the partially formed diapers232-1through232-N can be put into the FSI software. As an example, material property values for the middle portion244can be put into the FSI software so that the middle portion244can be configured as a flexible middle portion.

In various embodiments, a computer based CAE model can include one or more material properties that differ from material properties of the real world thing, in order for the overall model to account for inherent limitations of the model and/or to more accurately represent the overall physical behavior of the real world thing, as will be understood by one of ordinary skill in the art. In various embodiments of the model230, some of the portion of the continuous web of diaper materials231can be configured with one or more material properties that differ from material properties of a real world continuous web of diaper materials, in order for the overall model230to account for inherent limitations of the model230and/or to more accurately represent the overall physical behavior of a real world continuous web of diaper materials. For example, the model230is limited in that it represents only a portion of a continuous web. The model230of the portion231has ends edges, while a real world web of diaper materials would be continuous as it enters a diaper machine. As a result, the model230has an inherent limitation in that the portion231is not connected to upstream and/or downstream portions of a web as a real world continuous web of diaper materials would be.

If, in the model230, an end edge of the portion of the continuous web of diaper materials231is configured with material properties that are similar to material properties of a real world continuous web of diaper materials, so that the end edge is flexible, then, during the simulation of the model230, the end edge may tend to distort, bend, and/or curl, so that the edge may not completely accurately represent the physical behavior of a real world continuous web of diaper materials.

In order to address this difficulty, in a model of a portion of a continuous web of diaper materials, a leading edge and/or a trailing edge can include one or more portions configured with material properties that differ from material properties of a real world continuous web of diaper materials. These differing material properties can effectively represent physical constraints that would be provided by upstream and/or downstream portions of a real world continuous web of diaper materials. Specifically, the one or more portions can be configured with differing material properties to be sufficiently rigid so as to resist distorting, bending and/or curling. Any part or parts or all of an end edge can be configured to include one or more rigid portions,

In the embodiment ofFIG. 2B, the leading edge241includes a middle portion configured to be a rigid portion242. The rigid middle portion242is substantially centered on the longitudinal centerline222and extends laterally outward from the longitudinal centerline222to about the fold lines216. In various embodiments, the rigid middle portion242may not extend all the way out to the fold lines216. Since the rigid middle portion242is laterally inboard to the fold lines216, laterally outboard portions of the portion of the continuous web of diaper materials231can be folded along the fold lines216onto an inside of the diaper materials, as described in connection with the embodiments ofFIGS. 1A-1B. The leading edge241also includes flexible outer portions243, which are laterally outboard from the rigid middle portion242. The flexible outer portions243can be configured with material properties that are similar to or the same as material properties of corresponding portions of a real world continuous web of diaper materials, which may or may not be same the as the material properties of other portions of the chassis. Also, in the embodiment ofFIG. 2B, the trailing edge241is configured to be a rigid trailing edge242.

The model230of the portion of the continuous web of diaper materials231can also include a mesh. A mesh is a collection of small, connected polygon shapes that define elements in a CAE computer based model. A mesh can be generated by using commercially available meshing software. In some embodiments, the type of mesh and/or the size of mesh elements can be controlled with user inputs into the meshing software, as will be understood by one of ordinary skill in the art. The mesh for the portion of the continuous web of diaper materials231can be generated using commercially available meshing software. For clarity, a mesh is not illustrated in the embodiment ofFIGS. 2A and 2B.

The model230of the portion of the continuous web of diaper materials231can also include boundary conditions. Boundary conditions are defined physical factors which can interact with parts of a CAE computer based model. Examples of boundary conditions include forces, pressures, velocities, and physical constraints, each of which can be assigned a particular magnitude and direction and/or can be applied to a specific location within the model. Boundary conditions can act on the model in various ways, to move, constrain, and/or deform one or more parts in the model. Boundary conditions can be determined by observing, measuring, analyzing and/or estimating real world physical factors which can interact with a real world continuous web of diaper materials. In various embodiments, a computer based CAE model can include one or more boundary conditions that differ from real world physical constraints, in order for the overall model to account for inherent limitations of the model and/or to more accurately represent the overall physical behavior of the real world thing, as will be understood by one of ordinary skill in the art. Boundary conditions for the portion of the continuous web of diaper materials231can be put into the FSI software.

The model230includes boundary conditions of forces and velocities. The portion of the continuous web of diaper materials231includes the velocity227in the machine direction228, which is applied to the entire web, to simulate the real world movement of a continuous web of diaper materials in a diaper machine. In addition, the leading edge241and/or the trailing edge245can be directed along a particular pathway, to simulate physical constraints within a diaper machine.

The portion of the continuous web of diaper materials231also includes tensions resulting from the tensioning forces247, which can be distributed along end edges of the web, to simulate the real world tensions in a continuous web of diaper materials in a diaper machine. The tensioning forces247distributed along the leading edge241can be about equal or exactly equal in magnitude to the tensioning forces247distributed along the trailing edge245. The tensioning forces247distributed along the leading edge241can be directed generally in the machine direction228, while the tension forces247distributed along the trailing edge245can be directed generally opposite to the machine direction228. In various embodiments, some or all of the forces and/or velocities included in the model230can be determined in one or more prior simulations and subsequently applied to the model230.

The model230of the portion of the continuous web of diaper materials231can also include defined interactions between its parts and/or with part or all of one or more other CAE computer based models. The model230of the portion of the continuous web of diaper materials231is defined so that all of its parts can physically interact with each other. The model230of the portion of the continuous web of diaper materials231is also defined so that it can physically interact with all parts of a computer based model350of a portion of a diaper converting machine351, as described in connection with the embodiment ofFIG. 3. The model230of the portion of the continuous web of diaper materials231is further defined so that it can also physically interact with all parts of a computer based model470of air471,473, as described in connection with the embodiment ofFIGS. 4A and 4B. In various embodiments, one or more computer based CAE models can include one or more defined interactions that differ from real world physical interactions, in order to account for inherent limitations in the models and/or to more accurately represent the overall physical behaviors of the real world things, as will be understood by one of ordinary skill in the art. These interactions can be defined in the FSI software.

FIG. 3is a perspective view illustrating the computer based model230of the portion of the continuous web of diaper materials231of the embodiment ofFIG. 2A, and a computer based model350of a portion of a diaper converting machine351, for use in the diaper manufacturing process. The diaper converting machine is configured to convert a continuous web of diaper materials into individual diapers. The portion of the diaper converting machine351includes a roller352with a roller contact surface353and a roller axis354. The portion of the diaper converting machine351also includes a folding apparatus355with a folding contact surface356.

The roller contact surface353and the folding contacting surface356are surfaces configured for contact with the computer based model230of the portion of the continuous web of diaper materials231. The roller352is configured so that the portion of the continuous web of diaper materials231can be conveyed over the roller352. The folding apparatus355is configured so that the portion of the continuous web of diaper materials231can be folded by the folding apparatus355.

In various embodiments, a computer based model of a diaper converting machine can include any number of any kind of machine part or apparatus known in the art. For example, the diaper converting machine can include one or more rollers, folding apparatuses, bonding apparatuses, cutting apparatuses, etc.

The model350of the portion of the diaper converting machine351can be created by using FSI software. The model350can be created by putting in dimensions and material properties for the portion of the diaper converting machine351, generating a mesh, defining boundary conditions for the model350, and defining interactions between parts of the portion of the diaper converting machine351and other parts or models. By doing so, the computer based model350can be configured to accurately simulate the physical behavior of a real world diaper converting machine.

The portion of the diaper converting machine351can have dimensions that are similar to or the same as dimensions of a real world diaper converting machine. These dimensions can be determined by measuring real world parts of a diaper converting machine, by using documented dimensions for known parts, and/or by estimation. Values for the length, width, thickness, and/or other dimensions of the roller352and the folding apparatus355can be put into FSI software.

The portion of the diaper converting machine351can have material properties that are similar to or the same as material properties of a real world diaper converting machine. These material properties can be determined by measuring real world parts of a diaper converting machine, by using accepted values for known materials, and/or by estimation. Values for the mass, strength, coefficient of friction, and/or other mechanical properties of the roller352and the folding apparatus355can be put into the FSI software. As examples, material property values can be put into the FSI software so that the roller contact surface353has a coefficient of friction of about 1.0, and the folding contacting surface356has a coefficient of friction of about 0.1. In various embodiments, material property values for other coefficients of friction can also be used.

The model350of the portion of the diaper converting machine351can also include a mesh of machine elements which can be generated by using commercially available meshing software. In some embodiments, the size of these machine elements can be defined with user inputs into the mesh software. As an example, the size of machine elements for the portion of the diaper converting machine351can be defined such that substantially all of the machine element lengths are greater than or equal to about 1 millimeter and less than or equal to about 10 millimeters. Also as an example, the machine elements can be defined such that substantially all of the machine element lengths are about 5 millimeters. In various embodiments, user inputs for other machine element lengths can also be used. For clarity, the mesh is not illustrated in the embodiment ofFIG. 3.

The model350of the portion of the diaper converting machine351can also include boundary conditions. The model350includes boundary conditions of physical constraints. The roller352is physically constrained by boundary conditions to rotate about the roller axis354. The roller axis354is physically constrained by boundary conditions to maintain a fixed location and orientation in space, despite forces acting upon it. The folding apparatus355is also physically constrained by boundary conditions to maintain a fixed location and orientation in space, despite forces acting upon it. Boundary conditions for the roller352and the folding apparatus355can be put into the FSI software.

The model350of the portion of the diaper converting machine351can also include defined interactions between its parts and/or with part or all of one or more other CAE computer based models. The model350of the portion of the diaper converting machine351is defined so that all of its parts can physically interact with each other. The model350of the portion of the diaper converting machine351is also defined so that it can physically interact with all parts of the computer based model230of the portion of the continuous web of diaper materials231, as described in connection with the embodiment ofFIGS. 2A-2B. The model350of the portion of the diaper converting machine351is also defined so that it can physically interact with all parts of a computer based model470of air471,473, as described in connection with the embodiment ofFIGS. 4A and 4B. These interactions can be defined in the FSI software.

FIG. 4Ais a perspective view illustrating the computer based model230of the portion of the continuous web of diaper materials231of the embodiment ofFIG. 2A, the computer based model350of the portion of the diaper converting machine351of the embodiment ofFIG. 3, and a computer based model470of air471,473present in the diaper manufacturing process. The model470includes a first volume of air471and a second volume of air473. For clarity, air is illustrated as transparent, throughout the present disclosure.

The first volume of air471completely surrounds the portion of the continuous web of diaper materials231and completely surrounds the portion of the diaper converting machine351. In various embodiments, the first volume of air471may surround a portion or substantially all of the portion of the continuous web of diaper materials231and/or a portion or substantially all of the portion of the diaper converting machine351. The second volume of air473completely surrounds the first volume of air471. In various embodiments, the second volume of air473may surround a portion or substantially all of the first volume of air471. In some embodiments, the first volume of air471and/or the second volume of air473can include a number of smaller volumes of air.

FIG. 4Bis a cross-sectional view along section line4B-4B inFIG. 4A, illustrating the computer based model230of the portion of the continuous web of diaper materials231of the embodiment ofFIG. 2A, the computer based model350of the portion of the diaper converting machine351of the embodiment ofFIG. 3, and the computer based model470of the air471,473of the embodiment ofFIG. 4A.

The first volume of air471can have various dimensions, which can determine how much of the portion of the continuous web of diaper materials231and how much of the portion of the diaper converting machine351are surrounded by the first volume of air. The second volume of air471can also have various dimensions, which can determine how much of the first volume of air471is surrounded by the second volume of air473. While the first and second volumes of air471,473are illustrated as rectilinear shapes in the embodiment ofFIGS. 4A and 4B, the volumes can also take different shapes. Dimensions for the first volume of air471and for the second volume of air473can be put into FSI software.

The first volume of air471and the second volume of air473can each have material properties that are similar to or the same as material properties of real world air in and/or around a diaper converting machine. These material properties can be determined by measuring real world air in and/or around a diaper converting machine, by using accepted values for air, and/or by estimation. Values for pressure, temperature, and/or other gaseous properties for the first volume of air471and for the second volume of air473can be put into the FSI software.

In various embodiments, the second volume of air473can be configured at a particular constant pressure that is about equal to an atmospheric pressure (e.g. about 100 kPa), to simulate the surrounding atmosphere. The first volume of air471can, in some embodiments, be configured to allow pressure variations, to simulate local changes in pressure proximate to the portion of the continuous web of diaper materials231and/or to the portion of the diaper converting machine351.

The first volume of air471and the second volume of air473can also each include a mesh of air elements which can be generated by using commercially available meshing software. In some embodiments, the size of these air elements can be defined with user inputs into the mesh software. As an example, the size of air elements for the first volume of air471and/or the second volume of air473can be defined such that substantially all of the air element lengths are less than or equal to about two times the machine element lengths of substantially all of the machine elements of the model350of the portion of the diaper converting machine351. In various embodiments, user inputs for other air element lengths can also be used. For clarity, the mesh is not illustrated in the embodiment ofFIGS. 4A and 4B.

The first volume of air471and the second volume of air473can each also include boundary conditions. The first volume of air471and the second volume of air473each include boundary conditions of physical constraints. The first volume of air471and the second volume of air473are each physically constrained by boundary conditions to maintain a fixed location and orientation in space, despite forces acting upon it. Boundary conditions for the first volume of air471and the second volume of air473can be put into the FSI software.

The first volume of air471and the second volume of air473can each also include defined interactions with each other and/or with part or all of one or more other CAE computer based models. The first volume of air471is defined to allow air exchanges472with the second volume of air473, and vice versa, to simulate the real world movement of air. The first volume of air471and the second volume of air473are each defined so that they can each physically interact with all parts of the computer based model230of the continuous web of diaper materials231, as described in connection with the embodiment ofFIGS. 2A-2B. The first volume of air471and the second volume of air473are also each defined so that they can each physically interact with all parts of the computer based model350of the diaper converting machine351, as described in connection with the embodiment ofFIGS. 4A and 4B. These interactions can be defined in the FSI software.

FSI software can be used to simulate a physical behavior of the model230of the portion of the continuous web of diaper materials231interacting with the model350of the portion of the diaper converting machine351and moving through the model470of the air471,473. As a result, particular designs of a diaper converting machine and particular configurations of diapers and/or diaper materials can be evaluated and modified as computer based models before they are tested as real world things. FSI software can be similarly applied to simulate a physical behavior of models of part or all of one or more other disposable articles interacting with models of part or all of one or more machines for manufacturing such articles, and moving through a model of air.

FIG. 5Ais a plan view illustrating a computer based model538of an exemplary discrete piece of diaper trim material518.FIG. 5Bis a plan view illustrating a computer based model539of an exemplary portion of a continuous piece of diaper trim material519. The discrete piece of diaper trim material518and the portion of the continuous piece of diaper trim material519can be any kind of one or more materials, such as a film and/or a nonwoven. Each of the models538and539can be created by using FSI software. Each of the models538and539can be created, as described above, by putting in dimensions and material properties for the diaper trim material518or519, generating a mesh, defining boundary conditions for the model538or539, and defining interactions between parts of the diaper trim material519or519and other parts or models. By doing so, each of the computer based models538and539can be configured to accurately simulate the physical behavior of a real world diaper trim material.

FIG. 6is a perspective view illustrating the computer based model539of the portion of the continuous piece of diaper trim material519of the embodiment ofFIG. 5B, and a computer based model660of a portion of a trim removal apparatus661, for use in a diaper manufacturing process. The model660includes a portion of a conveyor662and a portion of a trim removal apparatus661. The portion of the trim removal apparatus661includes a nozzle663with a nozzle entrance664and a nozzle exit665. The nozzle entrance664is configured with a particular size and shape and is oriented above the portion of the conveyor662. The portion of the continuous piece of diaper trim material519rests on the portion of the conveyor662. During the diaper manufacturing process, the portion of the conveyor662moves with a velocity667in a conveyor direction668so that the portion of the continuous piece of diaper trim material519passes below the nozzle entrance664. The trim removal apparatus661is configured to physically transport the portion of the continuous piece of diaper trim material519through the nozzle entrance664using a vacuum. In various embodiments, a trim removal apparatus can be similarly configured to physically transport a discrete piece of diaper trim material.

The model660can be created, as described above, by putting in dimensions and material properties for the trim removal apparatus661, generating a mesh, defining boundary conditions for the model660, and defining interactions between parts of the trim removal apparatus661and other parts or models. By doing so, the computer based model660can be configured to accurately simulate the physical behavior of a real world trim removal apparatus.

FIG. 7Ais a perspective view illustrating the computer based model539of the portion of the continuous piece of diaper trim material519of the embodiment ofFIG. 5B, the computer based model660of the portion of the trim removal apparatus661of the embodiment ofFIG. 6, and a computer based model775of air present in the diaper manufacturing process. The model775includes a first volume of air776, a second volume of air778, and a third volume of air779.FIG. 7Aalso illustrates the portion of the conveyor662.

The first volume of air776completely surrounds the portion of the continuous piece of diaper trim material519and completely surrounds the portion of the trim removal apparatus661. In various embodiments, the first volume of air776may surround a portion or substantially all of the portion of the continuous piece of diaper trim material519and/or a portion or substantially all of the portion of the trim removal apparatus661. The second volume of air778completely surrounds the first volume of air776. In various embodiments, the second volume of air778may surround a portion or substantially all of the first volume of air776. The third volume of air779completely covers the nozzle exit665. In various embodiments, the third volume of air779may cover and/or surround a portion or substantially all of the nozzle exit665. In some embodiments, the first volume of air776and/or the second volume of air778and/or the third volume of air779can include a number of smaller volumes of air.

FIG. 7Bis a cross-sectional view along section line7B-7B inFIG. 7A, illustrating the computer based model539of the portion of the continuous piece of diaper trim material519of the embodiment ofFIG. 5B, the computer based model660of the portion of the trim removal apparatus661of the embodiment ofFIG. 6, and the computer based model775of the air776,778,779of the embodiment ofFIG. 7A.

Each of the volumes of air776,778,779can have various dimensions and shapes, which can determine the degree to which the volume can surround and/or cover other particular models or parts of models. Dimensions for the first volume of air776, the second volume of air778, and the third volume of air7779can be put into FSI software. Values for pressure, temperature, and/or other gaseous properties for the volumes of air776,778,779can also be put into the FSI software.

In various embodiments, the second volume of air778can be configured at a particular constant pressure that is about equal to an atmospheric pressure (e.g. about 100 kPa), to simulate the surrounding atmosphere. The first volume of air776can, in some embodiments, be configured to allow pressure variations, to simulate local changes in pressure proximate to the portion of the continuous piece of diaper trim material519and/or to the portion of the trim removal apparatus661. The third volume of air779can be configured at a second pressure that is less than the atmospheric pressure, in order to simulate a partial vacuum. The second pressure can, in various embodiments, be constant or variable.

Each of the volumes of air776,778,779can also include a mesh of air elements which can be generated, as described above, by using commercially available meshing software. Each of the volumes of air776,778,779can also include boundary conditions, physically constraining the volume to maintain a fixed location and orientation in space, despite forces acting upon it. These boundary conditions can be put into the FSI software.

Each of the volumes of air776,778,779can also include defined interactions with each other and/or with part or all of one or more other CAE computer based models. The first volume of air776is defined to allow air exchanges777with the second volume of air778, and vice versa, to simulate the real world movement of air. The first volume of air776and the second volume of air778are each defined so that they can each physically interact with all parts of the computer based model539of the portion of the continuous piece of diaper trim material519, as described in connection with the embodiment ofFIGS. 7A-7B. These interactions can be defined in the FSI software.

FSI software can be used to simulate a physical behavior of the model539of the portion of the continuous piece of diaper trim material519interacting with the model660of the portion of the diaper trim removal apparatus661and moving through the model775of the air776,778,779. As a result, particular designs of a diaper trim removal apparatus and particular configurations of diaper trim material can be evaluated and modified as computer based models before they are tested as real world things. FSI software can be similarly applied to simulate a physical behavior of models of discrete or continuous trim pieces of other disposable articles interacting with models of part or all of trim removal apparatuses, and moving through a model of air.

FIG. 8is a chart illustrating a method880of using computer based models of diapers and/or diaper materials, a diaper machine, and air, to simulate a physical behavior of diapers and/or diaper materials as they interact with a diaper machine and with air, in a diaper manufacturing process. The method880includes a first step881of creating a computer based model of a diaper and/or diaper materials. As an example, the computer based model in the first step881can be the computer based model230of the portion of the continuous web of diaper materials231, of the embodiments ofFIGS. 2A-4B, for use in a diaper manufacturing process. As another example, the computer based model in the first step881can be the computer based model538of the discrete piece of diaper trim material518, of the embodiment ofFIG. 5A, or the computer based model539of the portion of the continuous piece of diaper trim material519, of the embodiments ofFIGS. 5B-7B, for use in a diaper manufacturing process. In various embodiments, the computer based model of the first step881can be a computer based model of any number and/or amount of any kind of diaper and/or diaper materials, in any state of formation, with any number of any kind of diaper features, as described herein.

The method880includes a second step882of creating a computer based model of a diaper machine. As an example, the computer based model of a diaper machine in the second step882can be the computer based model350of the portion of the diaper converting machine351, of the embodiments ofFIGS. 3-4B, for use in a diaper manufacturing process. As another example, the computer based model of a diaper machine in the second step882can be the computer based model660of the portion of the trim removal apparatus661, of the embodiments ofFIGS. 6-7B, for use in a diaper manufacturing process. In various embodiments, the computer based model of the second step882can be a computer based model of any portion of any kind of machine for any kind of function in a diaper manufacturing process, as described herein.

The method880includes a third step883of creating a computer based model of air. As an example, the computer based model of air in the third step883can be the computer based model470of the air471,473of the embodiment ofFIGS. 4A-4B. As another example, the computer based model of air in the third step883can be the computer based model775of the air776,778,779of the embodiment ofFIGS. 7A-7B. In various embodiments, the computer based model of the third step775can be a computer based model of one or more volumes of air, as described herein.

In some embodiments of a method of simulating a physical behavior of a diaper and/or diaper materials in a diaper manufacturing process, the third step883may be omitted. For example, in circumstances where the effects of air on a diaper or diaper materials are known to be negligible, it may not be necessary to create and use a computer based model of air in the simulation. As another example, in preliminary simulations focused on basic interactions between the diaper and/or diaper materials and the diaper machine, it also may not be necessary to create and use a computer based model of air in the simulation.

Although the first step881, the second step882, and the third step883are described in numerical order in the present disclosure, any of these steps can be performed in any order, and/or at overlapping times, and/or at the same time, as will be understood by one of ordinary skill in the art.

The method880includes a fourth step884of simulating the interaction between the models. The fourth step884includes simulating the interaction between: the computer based model of the diaper and/or diaper materials from the first step881; the computer based model of the diaper machine from the second step882; and the computer based model of the air from the third step883. Prior to or during the fourth step884, the models to be interacted can be brought together.

In an embodiment of the present disclosure, the simulation of the fourth step884can simulate a physical behavior of the model230of the portion of the continuous web of diaper materials231interacting with the model350of the portion of the diaper converting machine351and moving through the model470of the air471,473, during a particular period of time. The simulation of the fourth step884can, in various embodiments, include simulating the physical behavior of the model230of the portion of the continuous web of diaper materials231being folded by the folding apparatus355, during a particular period of time. The simulation of the fourth step884can, in some embodiments, include simulating the physical behavior of the model230of the portion of the continuous web of diaper materials231being conveyed over the roller352, during a particular period of time. In another embodiment of the present disclosure, the simulation of the fourth step884can simulate a physical behavior of a model538or539of a diaper trim material518or519interacting with a model of a portion of a trim removal apparatus660and moving through a model775of the air776,778,779, during a particular period of time.

The method880includes a fifth step885of evaluating the simulation of the fourth step884. The evaluating can qualitatively and/or quantitatively evaluate any aspect of the physical behavior of any part or parts or some or all of the models being simulated. The evaluating can be performed by using computer data, measurements, or analysis, and/or by using information gained by human observation of the simulation. As an example, the evaluating can determine a particular period of time for a physical behavior to occur or not occur in the simulation. As further examples, the evaluating can evaluate a size, shape, orientation, or any other physical characteristic of any part or parts or some or all of the models being simulated at any time in the simulation. As still further examples, the evaluating can evaluate a force, pressure, velocity, or any other physical constraint of any part or parts or some or all of the models being simulated at any time in the simulation. In some embodiments of a method of simulating a physical behavior of a diaper and/or diaper materials in a diaper manufacturing process, the fifth step885may be omitted.

The method880includes a sixth step886of modifying one or more of the models used in the simulation of the fourth step884. In various embodiments, the modifying can be based on the evaluation of the fifth step885. In some embodiments of a method of simulating a physical behavior of a diaper and/or diaper materials in a diaper manufacturing process, the sixth step886may be omitted.

After the sixth step886is performed, the method880can be considered to be complete, or, optionally, some or all of the steps in the method880can be repeated. In other words, the method880can be performed as a single iteration or as multiple iterations. As an example, after the sixth step886is performed, the simulation of the fifth step885can be repeated, with one or more modified models, in order to evaluate the effect of any modifications, as will be understood by one of ordinary skill in the art.

Thus, the present disclosure includes methods of simulating the physical behavior of one or more diapers and/or diaper materials interacting with diaper machines and moving through surrounding air. Embodiments of the present disclosure can at least assist in predicting whether or not a particular diaper machine design can successfully process a particular configuration of a diaper and/or diaper materials. As a result, particular diaper machine designs and particular configurations of diapers and/or diaper materials can be evaluated and modified as computer based models before they are tested as real world things.