bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical Simulation of Injection/Compression Molding
Authors: Wang T. James 
Published: March 2022

Abstract
Injection/compression molding (ICM) is often referred to as coining, stamping, compressive-fill, or hybrid molding. It can produce parts with more homogeneous properties and less molded-in stresses, and this may not be possible with conventional injection molding. It can also produce extremely thin or large parts which may require larger machine if conventional injection molding were used.
A CAE software has been developed to simulate the ICM process. Two areas will be emphasized to show the advantage of the ICM process over the conventional injection molding process. One is the opening of the mold halves during the molding process allows resin flow to proceed to the extremities of the cavity more easily and consequently reduces the injection pressure and clamping force. Process window design will be discussed. The other is the packing due to the compression motion requires less pressure gradient, i.e., more effective packing. It results in more uniform and smaller pressure throughout the entire cavity. This is essential to produce parts with low residual stress such as compact disk and lens.
Mode Coupling Theory for Evanescent Wave Optical Fiber Sensors
Authors: Parnas Richard S. , Woerdeman Dara L. 
Published: March 2022

Abstract
Optical fiber based sensors have potential in the composites processing industry as well as many other industries, but cost and robustness often mitigate the advantages of optical fiber sensors. The least expensive type of optical fiber sensor is a length of fiber either embedded in the part or in distal contact with the part surface. In the case of embedded evanescent mode sensors, important issues hinge on interpreting the evanescent signal obtained during processing or in service inspection. An optical model based on mode coupling theory is presented below to provide a description of the sensing volume around the fiber from which signal is collected during evanescent measurements. The model is developed for a fluorescence sensor but the optical theory could be equally applied for infrared or other types of optical fiber sensors.
A Novel Process Control for Injection Molding Based Upon On-Line CAE Systems
Authors: Wang Pei-Jen , Lin Jin-Yow 
Published: March 2022

Abstract
A novel process control system for injection molding based on the integration of Computer Aided Engineering systems (CAE) and process control models has been studied and verified. The objective is to develop a scientific approach for on-line process control by making use of the results from the CAE systems. Initially, the design of injection molded products should be finished with the help of the CAE systems after the dimensions of the products have been determined. From a set of process conditions given by the CAE results, an automatic design of experimentation procedure was conducted for locating the processing window. The processing window was then employed as the CAE inputs for establishing a process model by employing adaptive fuzzy-neural networks. In addition, a set of quasi-optimal process condition was achieved if an optimization objective had been determined based on production requirement. Finally, appropriate cycle-to-cycle control actions on tuning process conditions were taken while the pertinent feedback signals from the process were stored. This process control methodology has been demonstrated with test cases showing promising results.
Orientation Formation in Planar Mold Filling: Theory and Numerical Predictions
Authors: He Jufang , Olivero Kristian A. , Altan M. Cengiz 
Published: March 2022

Abstract
Orientation formation in a steady, Newtonian, Hele-Shaw flow containing rigid, neutrally buoyant, slender fibers is numerically analyzed. The Hele-Shaw model is used to simulate flows through mold cavities consisting of thin planar sections. In this study, orientation results are calculated for a mold cavity containing a three to one sudden contraction. The suspension is injected from a single inlet gate at constant volume flow rate. Initially, the planar stream function is numerically solved by an Eulerian finite difference method to obtain the flow field. Subsequently, a Lagrangian particle tracking method is used to calculate the orientation field from the flow kinematics. The three-dimensional orientation formation throughout the mold cavity is obtained by a new method which calculates the second-order orientation tensors directly from flow kinematics and particle aspect ratio. With this new method, time-consuming integrals and inaccurate closure approximations commonly used in orientation calculations are avoided. The rotational dynamics of each particle are described by Jeffery’s theory. The numerical results are valid for multi-particle, dilute suspensions in which the orientation field can be fully described by the second-order moment of the orientation probability density function (OPDF). The orientation results are presented at different layers through the thickness of the mold cavity, ranging from the midplane to the top wall. In addition, the second-order orientation tensor is averaged through the mold thickness at a number of points in the vicinity of sudden contraction. These averaged orientation tensors are compared with the experimental data obtained from the same flow configuration by Olivero et al. (1997).
Calculation and Optimisation of the Feeding System in Thermoplastics Injection
Authors: Van Rutten N. , Dupret F. 
Published: March 2022

Abstract
During the filling stage of injection molding, important thermal phenomena take place in the mold feeding system. We present a non-isothermal model for the flow through the runners and the gates that permits us to accurately simulate the filling of thermoplastics parts. Comparison with experiments demonstrates the validity of our approach.
Learning About Design Concepts From Natural Functionally Graded Materials
Authors: Nogata Fumio 
Published: March 2022

Abstract
The goal of this report is to provide a new insight into nature as a source of inspiration for optimizing mechanical properties of structural components through functionally graded and/or multi-phased microstructures. It is shown that biological structure is designed to have uniform strength at all positions in both radial and axial directions. Design principles and processes in plants show that plants have a cell-based sensing system for external mechanical stimuli that plays a similar role as the piezoelectric effect in bones, i.e., mechanical stress/strain changes the stationary electric potential of plants, theryby influencing the growth activity of their load carrying members. The ingenious construction of some selected biomaterials demonstrates clearly that it would be better to spend more time and money on developing functionally graded materials governed by uniform strength; for example, structure using the optimal placement of fibers, various microstructures, porous or cellular structures, etc., rather than developing new materials with high-stiffness.
Reduction of Residual Stresses in a Two Dissimilar Materials Joint by Using a Functionally Graded Material
Authors: Yang Ying Yuan , Munz Dietrich 
Published: March 2022

Abstract
To reduce the residual stresses in a joint, especially those near the free edge of the interface, different approaches are possible. The best one is the introduction of a functionally graded material (FGM). In this paper the effect of the profile function in FGM on the residual stresses near the free edge of the interface and in the center of the joint will be discussed. It is shown that the residual stress in the joint can be reduced significantly by introducing a favorable FGM interlayer and that the stresses in the joint can be minimized by varying the profile function of the FGM. Finally, the effect of the stress jump at the interface on the failure behavior will be presented and the advantages of a joint with a graded material will be shown.
Crack Initiation in Notched Unidirectional Graphite/Epoxy Composites
Authors: Chow C. L. , Yang Fan , Fang H. Eliot 
Published: March 2022

Abstract
The paper describes an investigation examining damage responses and failure characteristics of unidirectional graphite/epoxy composites containing a central circular hole subjected to off-axis uniaxial tension. A recently developed damage mechanics model is extended to determine the progressive damage process around the hole and the effect of such damage on the in-plane behaviors and final failure of the notched composites. The generalized stress and strain constitutive equations and the relationship between the damage variable and material properties are briefly outlined first. The anisotropic mechanical behavior of the composites is investigated by using a nonlinear finite element procedure incorporated with the damage-coupled constitutive equations. As the failure of fiber reinforced composite materials may basically be either fiber dominated or matrix dominated, separate damage criteria are proposed to capture fiber failure and matrix or fiber/matrix interaction failure in unidirectional composites. The damage model is validated by comparing the numerical prediction and experimental data obtained from a Moiré interferometry technique. Preliminary results indicate that the proposed damage model provides an effective alternative method to study progressive failure behavior in unidirectional composites.
Effects of Out-of-Plane Deformation on Stress Rupture of Unidirectional Polymer Matrix Composites
Authors: Mahieux Céline A. , Reifsnider Kenneth L. 
Published: March 2022

Abstract
The use of composite materials instead of conventional engineering materials is more frequently considered, especially for applications with dominant weight constraints. Polymer matrix composites offer advantages such as relative ductility or lower cost of manufacturing compared to other composites. The different cases of loading for these materials need to be explored. Out-of-plane loading is an important case, and the literature is sparse when it comes to large displacements for these materials. Such large displacements can occur for a variety of applications. Some unidirectional fiber reinforced polymer matrix composites are, for example, stocked in rolled tapes. Even at room temperature, this large deflection of the material could result in the degradation of its properties over a long period of storage. In service, the bending load can be combined with thermal or chemical loads. Intuitively, the combination of the mechanical load and elevated temperature could accelerate the degradation process. The practical case that lead to this research was the study of polymer matrix composites for replacement of one layer of the steel armor in flexible pipes used by the oil industry in ocean water. The temperature of the oil circulating inside the pipe creates an elevated temperature. The effects of the combination of the quasi-static bending load intrinsic to the pipe geometry and aggressive environments are unknown and need to be investigated.
The present paper relates the recent advances in characterizing stress rupture for unidirectional carbon fiber reinforced polymer matrix composites in end-loaded bending and extends our earlier modeling efforts (Russell et al., 1997, Mahieux et al., 1997). Experimental observations are presented, and three life-prediction models are discussed in the following sections.
An Investigation of Crack/Microstructure Interaction in a Layered Intermetallic Composite
Authors: Wang Rong , Ye Fan , Katsube Noriko , Soboyejo Wole 
Published: March 2022

Abstract
The results of a recent study of the crack/microstructure interactions in layered MoSi2/Nb composites are presented. Toughening by crack bridging and blunting mechanisms will be modeled in using micromechanics concepts. Finite element models for the prediction of interfacial debonding and mixed mode crack growth are also presented. The paper will highlight use of combined mechanics and materials approaches in the engineering of damage tolerant intermetallic matrix composites.
Thermal Residual Stress Analyses of Nextel 440/Aluminum Composite
Authors: Nayeb-Hashemi Hamid , Yang Yimin 
Published: March 2022

Abstract
Finite element analyses were performed in order to evaluate the residual stresses developed during fabrication process of the Nextel 440/Al-6061 composite. The Nextel 440 fiber has a square section with two half circle attached to the opposite sides geometry. The purpose of the analyses was to find out the effect of fiber orientation and fiber spacing on the thermal residual stresses in the composite after the composite was cooled down to room temperature. It was found that high compressive stresses developed between two fibers and the absolute value of the compressive stresses increased as the two fibers approached each other. However, significant tensile stresses developed between fibers once the two fibers touched each other. The transition from compression to tension could be explained by considering the force balance between contacting fibers. It seems that the residual stresses around fibers are not significantly affected by the boundary conditions of the unit cell models. But the effect of the fibers on the thermal residual stresses of the matrix is seen all over the matrix material. The normal stresses on the fiber/matrix interface is higher when the two fibers are orientated at 45 degrees to each other, than those when the two fibers are orientated at zero degree to each other. The normal stress at the fiber/matrix interface for this fiber geometry was higher compared to that would have developed if round fibers were used.
Transport in Fibrous Battery Electrode Substrates
Authors: Sastry A. M. , Cheng X. , Choi S. B. 
Published: March 2022

Abstract
Advanced fibrous electrode substrates for use as substrates for the nickel electrodes in NiMH automotive cells are being studied analytically and experimentally. The electrodes must resist local failures under hundreds of charge/discharge cycles, during which these fibrous networks (impregnated with active material) are subjected to swelling loads induced by the cell electrochemical reaction. These fibrous materials can be effectively used as substrates for chemical reactions because of their combinations of high surface area and high conductivity. It is shown here these materials’ conductivity can be characterized using a statistical technique in conjunction with an adaptation of a classic continuum model. These approaches are presented here, and compared with experimental data on conduction in fibrous media. The new approach provides an efficient way of predicting the gradual loss in performance observed in battery materials.
Novel Processes for Fabricating Ceramic Composites and Future Outlook for Markets and Applications
Authors: Sheppard Laurel M. 
Published: March 2022

Abstract
Ceramic matrix composites (CMCs) can be broken down into two major classes: discontinuously reinforced and continuously reinforced. Discontinuously reinforced CMCs consist of a matrix phase (typically alumina or silicon nitride) to which a reinforcing phase (such as silicon carbide particles, platelets or whiskers) is added. This type of CMC is in the early stage of commercialization in applications where wear is a major issue such as cutting tools and extrusion dies.
Continuous fiber reinforced CMCs consist of an array of continuous ceramic fibers, either uniaxially arrayed, multi-axially arrayed, or woven as a cloth, that are embedded in a ceramic or glass matrix. This type of CMC is currently at the pre-commercial development/application demonstration stage for applications where high temperatures and high stresses occur. Such applications include gas turbine components and heat exchangers.
Statistics of Strength of Elastic-Brittle Composite Materials
Authors: Ostoja-Starzewski M. , Alzebdeh K. , Jasiuk I. 
Published: March 2022

Abstract
We study crack patterns and effective stress-strain response in unidirectional fiber-matrix composites subjected to out-of-plane and in-plane loading. The fibers are aligned in the longitudinal direction and arranged randomly, with no overlap, in the transverse plane. The fibers and the matrix are isotropic and elastic-brittle, which allows a parametrization of a wide range of composites in terms of a stiffness ratio and a strain-to-failure ratio. The analysis is carried out numerically using very fine two-dimensional spring networks permitting simulation of the crack initiation and propagation by sequentially removing bonds which exceed a local fracture criterion. Particular attention is given to the effects of scale and geometric randomness in these composites. We consider several “windows of observation” (scales) and study crack patterns, types of constitutive responses, and statistics of the corresponding scale dependent effective elastic stiffness and strength of such composites.
Effect of Holding Time on Damage State in a Thermal Barrier Coating
Authors: Nusier S. Q. , Newaz G. M. , Chaudhury Z. A. , Ahmed T. 
Published: March 2022

Abstract
Spallation is a major failure condition experienced by thermal barrier coatings (TBCs) subjected to thermal and mechanical loads. Although evidence of spallation is substantiated and mechanistic models to describe the failure condition is prevalent in literature, the progressive nature of damage evolution leading to spallation has not been addressed adequately. In this study, the effect of holding time on damage evolution in partially stabilized zirconia TBC on Nickel-based single crystal superalloy, Rene N5, was studied. Button specimens with Electron Beam - Physical Vapor Deposition (EB-PVD) TBC coating were thermally cycled. The bond coat was PtAl. Two different thermal cycle profiles were used to assess damage development. Damage state was tracked using microscopy and thermal wave imaging technique on samples subjected to a series of thermal cycles. It was found that if the sum of hold times at the same peak temperature are kept constant for two different thermal cycles profiles, similar damage states can be obtained.
Similitude of Failure and Size Effect in Fiber Composites
Authors: Bažant Zdeněk P. 
Published: March 2022

Abstract
The present brief paper reviews recent test resuts at Northwestern University and to briefly outlines some new theoretical, experimentally yet unconfirmed, deductions for the law governing the size effect in failures with an asymptotic residual stress in the crack, which may be either tensile, due to unbroken crack-bridging fibers, or compressive, due to buckling of fibers in a kink band treated apporoximately as a compression crack. This law is of approximate nature and ensues as a simple asymptotic matching of the size effects for small and large structural sizes.
Analytical Simulation of Strength Size Effect in Composite Materials
Authors: Tabiei Ala , Sun Jianmin 
Published: March 2022

Abstract
This paper presents a theoretical analysis of strength size effect associated with the length, width, and thickness of laminated composites. The presented expressions for prediction of the reliability use the Equal Load Sharing Rule (ELS Rule) which are determined by sequential multi-step failure of single lamina or sublaminate. The developed equations are validated using two sets of experimental data obtained from published data. The influence of the length, width, and thickness on the ultimate strength of laminated composites is demonstrated. Strength size effect is analyzed for the inplane strength parameters. The developed size effect equations are implemented in a user defined subroutine UMAT in the finite element code ABAQUS to demonstrate their applicability in numerical analysis.
Nonlinear Analysis of Curved Composite Panels Subjected to Combined Temperature Gradient and Mechanical Loads
Authors: Noor Ahmed K. , Peters Jeanne M. 
Published: March 2022

Abstract
The results of a detailed study of the effect of cutout on the nonlinear response of curved unstiffened panels are presented. The panels are subjected to combined temperature gradient through-the-thickness combined with pressure loading and edge shortening or edge shear. The analysis is based on a first-order shear-deformation Sanders-Budiansky type shell theory with the effects of large displacements, moderate rotations, transverse shear deformation and laminated anisotropic material behavior included. A mixed formulation is used with the fundamental unknowns consisting of the generalized displacements and the stress resultants of the panel. The nonlinear displacements, strain energy, principal strains, transverse shear stresses, transverse shear strain energy density, and their hierarchical sensitivity coefficients are evaluated. The hierarchical sensitivity coefficients measure the sensitivity of the nonlinear response to variations in the panel parameters, as well as in the material properties of the individual layers. Numerical results are presented for cylindrical panels and show the effects of variations in the loading and the size of the cutout on the global and local response quantities and their sensitivity to changes in the various panel, layer and micromechanical parameters.
Minimization of the Periodic Thermoelastic Deformation in Space Structures by Active Loads
Authors: Rand Omri , Givoli Dan 
Published: March 2022

Abstract
The paper presents a numerical scheme for the open-loop optimal control of the thermoelastic deformation of space structures. The space structure response and the control loads are assumed to be periodic in time, with a given period. The numerical methodology is based on a finite element-harmonic balance procedure which is tailored with an adequate optimization scheme. Various cost functionals are considered, which involve the elastic deformation of the structure and include penalties on the control magnitudes. The performance of the thermoelastic and control schemes are demonstrated via numerical examples.
Thermoelastic Analysis of Laminated Composite Plates and Shells Based on High-Order Theory
Authors: Verijenko Viktor E. , Tauchert Theodore R. , Adali Sarp , Scott Murray L. , Shaikh Chippy S. 
Published: March 2022

Abstract
Due to increased use of laminated composite plates and shells as a primary structural elements the requirements of their analysis and design are constantly moving to a significantly higher level. The understanding of behaviour of these structures under different loading conditions including such as thermal, static, dynamic and their combinations becomes of paramount importance for the safe design. In the present paper a derivation of a new higher-order theory for the analysis of thermoelastic composite plates and shells is presented. The theory based on kinematic hypothesis which were derived on the basis of iterative technique, and it takes into account transverse shear deformations. It is shown that the results obtained on the basis of this theory are accurate and that the theory allows to improve understanding of the response of laminated composites under thermal and static loading.