bluuebunny/crossref_metadata_2025 huggingface dataset:
An Examination of the Factors Associated With Implementation of Evidence‐Based Management Practices for Improving Nurse Work Environments
Authors: Djukic Maja , Jun Jin , Fletcher Jason
Published: March 2021

Background

Evidence‐based management practices (EBMPs) that improve nurses’ work environments have been linked to improvements in patient outcomes such as patient satisfaction and mortality. Yet, the extent to which nurse managers implement these EBMP or the factors associated with their implementation is not known.

Aims

Guided by the Promoting Action on Research Implementation in Health Services (PARIHS) Framework, we examined individual, evidence, and organizational characteristics associated with nurse managers’ implementation of the five EBMPs.

Methods

A cross‐sectional, correlational, survey design was used. Nurse managers from 10 public hospitals in New York City were recruited. Evidence and contextual variables were measured with the Organizational Readiness for Change Assessment instrument. EBMPs were measured with a modified version of the Practice Environment Scale of the Nursing Work Index. All multi‐item scales were validated with confirmatory factors analysis in the studied sample. Additionally, the scales had Cronbach’s alpha reliability greater than .8. A multivariate linear regression analysis with robust standard error correction was used to analyze the data and to adjust for clustering of managers in hospitals.

Results

A total of 331 nurse managers responded for a 47.4% response rate. Bachelor’s degree, number of staff supervised, managers’ personal experience with evidence for EBMPs, staff culture, and organizational resources were significant predictors of nurse managers’ implementation of EBMPs for NWE improvement (p < .05).

Linking Evidence to Action

Staff culture was positively associated with implementation of all five EBMPs for improving nurses’ work environments. Managers should prioritize nursing unit culture that encourages staff to innovate and change in order to improve care.
Use of Pain Management Champions to Enhance Guideline Implementation by Care Workers in Nursing Homes
Authors: Brunkert Thekla , Simon Michael , Zúñiga Franziska
Published: March 2021

Background

Underutilization of evidence‐based pain management in nursing homes (NHs) is common. Evidence toward effective approaches to improve adoption of evidence‐based practices in NHs is limited. Application of theory in evaluation approaches can increase understanding of implementation challenges.

Aim

To get a better understanding of the impact of implementation strategies by exploring the underlying mechanisms using behavioral theory.

Methods

This mixed‐methods study is embedded in an implementation‐effectiveness study of a pain management guideline in four Swiss NHs. To evaluate our implementation strategies, training workshops were held, and trained pain champions were introduced. We also developed a conceptual framework. Based on Bandura’s self‐efficacy theory, we hypothesized how our implementation strategies might affect changes in care workers’ behavior. Care workers’ questionnaire surveys were conducted at baseline (n = 136), after 3 months (n = 99), and after 6 months (n = 83) to assess self‐efficacy in pain management and self‐reported guideline adoption. We computed linear mixed‐effect models to assess changes over time in self‐efficacy and logistic regressions to assess associations between self‐efficacy and guideline adoption. Concurrently, we conducted focus groups with care workers (n = 8) to explore their response to the implementation strategies.

Results

Overall, there was a significant increase in self‐efficacy at both time points (p < .001). We found significant associations between self‐efficacy and adoption of two guideline components, that is, performing a comprehensive pain assessment and using observational pain assessment tools in cognitively impaired residents. Qualitative findings showed that implementation strategies were received positively by care workers. Focus group participants reported more attentiveness to residents’ pain experience. The participants also reported increases in assessment and documentation of pain with more detail than before.

Linking Evidence to Action

Our findings highlighted that the training and use of pain champions increased self‐efficacy and thereby induced behavior change leading to guideline adoption. Regarding persistent implementation challenges, a theory‐based conceptual model contributes to the overall understanding.
Large Eddy Simulation of Lean Mixed-Mode Combustion Assisted by Partial Fuel Stratification in a Spark-Ignition Engine
Authors: Xu Chao , Som Sibendu , Sjöberg Magnus
Published: March 2021

Partial fuel stratification (PFS) is a promising fuel injection strategy to improve the stability of lean combustion by applying a small amount of pilot injection right before spark timing. Mixed-mode combustion, which makes use of end-gas autoignition following conventional deflagration-based combustion, can be further utilized to speed up the overall combustion. In this study, PFS-assisted mixed-mode combustion in a lean-burn direct injection spark-ignition (DISI) engine is numerically investigated using multi-cycle large eddy simulation (LES). A previously developed hybrid G-equation/well-stirred reactor combustion model for the well-mixed operation is extended to the PFS-assisted operation. The experimental spray morphology is employed to derive spray model parameters for the pilot injection. The LES-based model is validated against experimental data and is further compared with the Reynolds-averaged Navier–Stokes (RANS)-based model. Overall, both RANS and LES predict the mean pressure and heat release rate traces well, while LES outperforms RANS in capturing the cycle-to-cycle variation (CCV) and the combustion phasing in the mass burned space. Liquid and vapor penetrations obtained from the simulations agree reasonably well with the experiment. Detailed flame structures predicted from the simulations reveal the transition from a sooting diffusion flame to a lean premixed flame, which is consistent with experimental findings. LES captures more wrinkled and stretched flames than RANS. Finally, the LES model is employed to investigate the impacts of fuel properties, including heat of vaporization (HoV) and laminar burning speed (SL). Combustion phasing is found more sensitive to SL than to HoV, with a larger fuel property sensitivity of the heat release rate from autoignition than that from deflagration. Moreover, the combustion phasing in the PFS-assisted operation is shown to be less sensitive to SL compared with the well-mixed operation.
Effect of Reynolds Number on Five-Hole Probe Performance: Experimental Study of the Open-Access Oxford Probe
Authors: Passmann Maximilian , der Wiesche Stefan aus , Povey Thomas , Bergmann Detlef
Published: March 2021

There is relatively little literature concerning the effect of Reynolds number on multi-hole aerodynamic probe performance. In particular, there is almost no discussion in the literature regarding the underlying mechanisms of Reynolds number (Re) sensitivity for such probes. In order to close this gap, detailed investigations of the effect of Re on a five-hole probe have been performed using both particle image velocimetry (PIV) techniques and oil flow visualizations. Wind- and water-tunnels were used to cover a wide range of Re. The open-access Oxford Probe was used for these studies because of the readily available data-sets and processing routines and to allow future comparisons by other authors. Complex flow dynamics including flow separation and re-attachment were identified, which cause Re-sensitivity of the calibration map at low Re even for low yaw or pitch angles. By comparing calibration maps across a wide range of Re, we demonstrate that the Oxford Probe can be employed without much loss of accuracy at lower Re levels than initially (conservatively) suggested, and quantify the errors in the extreme low-Re regime. Overall, we demonstrate the robustness of the Oxford Probe concept across a wide range of Re conditions, we more clearly defined the low-Re limit for the probe design and quantify errors below this limit, and we illustrate the fundamental mechanisms for Re-sensitivity of multi-hole probes.
Comparison of Endwall Loss Reduction Techniques in a High-Lift Turbine Passage
Authors: Marks Christopher R. , Fletcher Nathan , Sondergaard Rolf
Published: March 2021

The development of techniques that reduce the losses in the endwall region is an important area of research as it supports an increase in the turbine design space through the use of higher lift blade designs while maintaining high efficiency. Several active and passive shape contouring methods that reduce losses generated by the secondary flow have been developed and investigated on a high-lift front-loaded low-pressure turbine research profile in a low-speed linear cascade configuration. This paper summarizes and compares alterations to the three-dimensional secondary flow field by the application of three different techniques: blade profile contouring, optimized endwall shape contouring, and localized low mass coefficient jets. Each method was applied to identical research blade profiles and compared in the same linear cascade wind tunnel resulting in a unique perspective into the loss reduction mechanisms associated with each technique. The design strategy will be discussed along with a detailed description of changes to the secondary flow field using in- and out-of-passage total pressure loss measurements and high-speed stereoscopic particle image velocimetry. The key findings include the loss reduction mechanisms associated with each approach and the manipulation of key endwall flow structures such as the passage vortex and a strong suction surface corner separation.
Dynamics of a Rotating Flexible Multi-Link With Viscoelastic Constraining Layers
Authors: Tzou H. S. , Wan G. C.
Published: March 2021

Due to an increased flexibility of modern mechanical and structural systems, effective vibration control becomes essential to their high-precision operations. In this paper, dynamics and vibration control of a rotating multi-link are studied. Passive vibration control of the link with distributed viscoelastic layers is studied. Effectiveness of the distributed viscoelastic dampers with various stiffness and damping properties is investigated.
Finite Element Formulation for Dynamic Analysis of Planar Flexible Beams With Finite Rotations
Authors: Iura M.
Published: March 2021

An efficient formulation for dynamic analysis of planar Timoshenko’s beam with finite rotations is presented. Both an inertial frame and a rotating frame are introduced to simplify computational manipulation. The kinetic energy of the system is obtained by using the inertial frame so that it takes a quadratic uncoupled form. The rotating frame together with the small strain assumption is employed to derive the strain energy of the system. Since the exact solutions for linear static theory of Timoshenko’s beam are employed to obtain the strain energy, the present stiffness operator is free from the shear locking without using any special technique. Nonlinear effects appear only in the transformation of displacement components between global and local coordinates. This results in a drastic simplification of nonlinear dynamic analysis of flexible beams. Numerical examples, including a planar mechanism, demonstrate the accuracy and efficiency of the present formulation.
Feature-Based Computer Integrated Inspection
Authors: Marefat Michael M.
Published: March 2021

This paper presents an approach to knowledge-based inspection planning for solid objects. The goals of intelligent inspection planning include determining (i) which entities (edge segments, etc) of the object should be measured, (ii) what camera locations and viewing directions should be used to perform inspection, and (iii) how can the search for these entities, and their inspection be robustly and efficiently done once the sensor data is obtained. An effective solution to this problem is clearly very important not only from the automation point of view, but also in order to effectively gather and use sensor information to overcome the volume and complexity of required information for adequate performance. In order to achieve the inspection planning goals, several interrelated problems must be solved. These problems include: (i) developing hierarchical representation mechanisms to effectively capture the knowledge about geometric entities, their relationships, sensors, and plans, (ii) reasoning mechanisms to determine the different attributes of the different features of object to be inspected, and the alternative strategies which can be used for inspection of each attribute, (iii) strategies for setting the sensor parameters, such as the position and viewing direction of the cameras, and methods to determine the visible entities in each configuration, and (iv) plan optimization. Our prototype is developed in the Smalltalk object oriented environment.
A Structured Sign for the Guidance of Autonomous Mobile Robots
Authors: Sai Heshin , Okawa Yoshikuni
Published: March 2021

For the explicit purpose of guiding autonomous mobile robots on wide and flat planes, we propose a specially designed guiding sign. It consists of a cylinder with four slits on its surface, and a fluorescent light on the center axis of the cylinder. Two outer slits are parallel to each other, and the other two inner slits are angled. A robot takes an image of the sign with a TV camera. By the threshold operation, it has four bright sets of pixels each of which corresponds to one of the four slits of the cylinder. By measuring the relative distances between those four bright blobs in the image plane, the robot can compute its distance and angle to the direction of the sign using two simple geometrical equations.

We have built a mobile robot and a sign. Using a personal computer with an image processor, we have evaluated the accuracy of the proposed method of position and angle measurement, and compared them with the theoretical analysis. The data show good coincidence with the analytical results. We have programmed the characteristics of the measurement, which is called the simulation program. First, the parameters in the simulation program are adjusted. Next, we have done several trajectory following experiments using this simulation program. The simulation program provides us with the results which could not be taken in the actual experiment.
AXITURB: A Full Computer Implementation of the NASA Design Procedure for Axial-Flow Turbines
Authors: Lu P. C. , Wang Chen-Ying
Published: March 2021

A recent task to design a Rankine-cycle space-power turbine system employing eutectic alloys of alkali metals prompted the present authors to re-examine the NASA design procedure for axial-flow turbines, as outlined by Glassman and Futral (and based on works of Stewart) in 1963. After clarifying the role of the singular case of a single-stage turbine, and organizing the procedure in clear steps, a computer program AXITURB was written. The present paper reports essentially the success of AXITURB in performing parametric studies of NaK and CsK turbines (using 78.4% and 23.1%, respectively, of potassium by weight), after re-generating all the reported NASA designs for turbines employing pure Na, K and Cs. An outline of design steps is also given. AXITURB has been put in public domain. Its heavily commented source code in FORTRAN is available to designers for adaption or modification.
Automatic Feature and Tolerance Modeling for in-Process Verification of 2D Punch Press Parts
Authors: Korngold Jacob , Kraft Russ , Luscher Tony , Lee Minsup , Shenoy Gopal
Published: March 2021

The objective of this project was to streamline the in-process verification of 2D sheetmetal parts by providing a vision based inspection workstation and software applications for the inspection planner. The goal was to develop an interactive inspection planning application which reads an IGES file representing an unfolded blank, and automatically generates inspection plans and setup instructions for the inspection workstation. The inspection workstation automatically executes the inspection plan and generates an inspection report for the part. The workstation and planning applications were successfully demonstrated for a family of sheetmetal features including holes, slots, rectangles, hexagons, keyholes, and patterns. Use of the system resulted in dramatic lime savings over manual inspection methods.
Knowledge Based Expert Systems for CAD/CAM Experience of an EDM Application
Authors: Kiritsis D. , Porchet Michel , Boutzev L. , Zic I. , Sourdin P.
Published: March 2021

In this paper we present our experience from the use of two different expert system development environments to Wire-EDM CAD/CAM knowledge based application. The two systems used follow two different AI approaches: the one is based on the constraint propagation theory and provides a natural language oriented programming environment, while the other is a production rule system with backward-forward chaining mechanisms and a conventional-like programming style. Our experience showed that the natural language programming style offers an easier and more productive environment for knowledge based CAD/CAM systems development.
Shock Spectra of an Armored Vehicle With Cutouts Using ADINA
Authors: Gupta Aaron D. , Wisniewski Henry L.
Published: March 2021

Light combat vehicles are playing an important support role for both troops and other heavily armored combat vehicles. As such, they have a much greater risk than in previous roles of being subjected to transient loads such as impact and overpressure loads. Propagation of ballistic shock from an impacted region to the critical locations and attachment points for secondary systems can cause damage and misalignment to sensitive equipments contributing to malfunction and reduction of vehicle performance. Accuracy of determination of dynamic response of these vehicles is directly dependent on the degree of refinement of the generated model and how well the model incorporates the essential features of the vehicle and correlates to its important characteristics without being over-burdened by non-essential details. Additionally, response of nonlinear components of the vehicle in high frequency regime may influence the overall global response of the vehicle. As a result, hatch openings and access door cutouts with unsymmetric locations may have to be incorporated in the finite element model to allow fair comparison with first order experiments involving a stripped vehicle hull. The current study is an attempt to assess the influence of multiple rectangular cutouts on the overall transient response of a vehicle hull subjected to a side-on impact load.
A Computer Aided Process Planning System for Milling Operations
Authors: Muju M. K. , Shanker Kripa , Aherrao P. K.
Published: March 2021

This paper presents some details of design and implementation of a computerized process planning system for parts requiring milling operations. The interactive system uses generative approach of process planning. The system is capable of handling end milling, face milling and peripheral milling.

The geometric programming technique is used for determining the optimal machining parameters. Emphasis is laid on the constraining equations used in the optimization model. The power equations are derived from basic metal cutting analysis. The cutter selection is automatic to some extent.

The system outputs detailed process plans giving sequence of operations, optimal machining parameters, cost per piece and production rate.
Finite Element Modeling for Prediction of Residual Stresses in Fiber Reinforced Metal Matrix Composites
Authors: Rangaswamy Partha , Jayaraman N.
Published: March 2021

In metal matrix composites residual stresses developing during the cool-down process after consolidation due to mismatch in thermal expansion coefficients between the ceramic fibers and metal matrix have been predicted using finite element analysis. Conventionally, unit cell models consisting of a quarter fiber surrounded by the matrix material have been developed for analyzing this problem. Such models have successfully predicted the stresses at the fiber-matrix interface. However, experimental work to measure residual stresses have always been on surfaces far away from the interface region. In this paper, models based on the conventional unit cell (one quarter fiber), one fiber, two fibers have been analyzed. In addition, using the element birth/death options available in the FEM code, the surface layer removal process that is conventionally used in the residual stress measuring technique has been simulated in the model. Such layer removal technique allows us to determine the average surface residual stress after each layer is removed and a direct comparison with experimental results are therefore possible. The predictions are compared with experimental results of an eight-ply unidirectional composite with Ti-24Al-11 Nb as matrix material reinforced with SCS-6 fibers.
Stress and Stability Analyses of Thick Fiber Reinforced Laminated Composite Plates Using Finite Element Method
Authors: Sulaiman Altaf H. , Yang Jim Y. C. , Jeelani Shaik
Published: March 2021

The Finite Element work consists of Stress Concentration at the edge of circular cutout of a fiber reinforced laminated plate and Stability analysis of the same model. Location and magnitude of the maximum circumferential stress have been investigated with a finite element analysis program, ABAQUS. Variations of fiber orientation and ratio of in-plane biaxial loading have been considered to study the behavior of angle ply laminated plates. Postbucking response for angle ply laminated plate [θ/−θ]2s for both thin and thick section is studied. Different hole sizes, loading ratios, geometric imperfection in the z-direction and fiber orientations have been used in this analysis. The influence of these parameters on the postbuckling response is presented in this paper.
Computer Simulation of Three-Dimensional Mechanical Assemblies: Part I — General Formulation
Authors: Fang Yong , Liou F. W.
Published: March 2021

In Part I of this paper, a dynamic modeling system for the simulation of three dimensional mechanical assemblies is presented. With this simulation tool, a designer can interactively create an assembly of mechanical components ready for dynamic analysis. The modeling system presented in this paper includes the derivation of the equations of motion of spatial multi-body systems, and the formulation of the equations to model the associated collision detection and collision responses. Part II of this paper is to introduce the geometry modeling and computer simulation of 3D systems.
Computer Simulation of Three-Dimensional Mechanical Assemblies: Part II — Computer Simulation
Authors: Chou T. C. , Liou F. W.
Published: March 2021

Computer simulation of the kinematic and dynamic behaviors of mechanical assemblies has become a very important tool in design and manufacturing, because the designer can foresee how a product is going to perform before the product is actually fabricated. However, up to now, the most current simulation modules are based on analysis from another kinematic or dynamic module by specifying the mating conditions between components, and then displaying the motion on the screen. This computer simulation actually performs similarly to a movie, and can only provide visual checking. The drawback of this simulation approach is that designers are forced to use the available joint models, and may lose their creativity. In part I of this paper, general mathematical modeling of the multi-body system is presented, while part II of this paper, a prototype convex-feature modeling system is presented with which a designer can interactively create an assembly of mechanical components ready for dynamic analysis. It can provide a state-of-the-art technology for real simulation of any mechanical systems, and act as a cost-effective test bed for concepts, final design, and control algorithms.
Design and Analysis of Mechanical Systems Using Electronic Spreadsheet Packages
Authors: Khosrowjerdi Mohammad , Sniezak Gary A.
Published: March 2021

In the past decade, sophisticated mathematical, statistical and graphical routines have been added to spreadsheet packages, thus converting them to serious analytical tools. The engineering community has adopted these packages to perform various sensitivity analyses on design problems which lend themselves to these types of applications. Design engineers can now rapidly and conveniently utilize these tools to perform a wide variety of analyses on design problems having simple geometries and loading conditions, without having to develop any FORTRAN, Basic or C code.

This paper is concerned with the applications of spreadsheet packages in the area of steady and transient thermal analysis, design optimization and solution of initial-value differential equations. Lotus 1-2-3 in conjunction with the explicit finite difference method (Gauss-Seidel method) has been used to predict transient temperature distribution in an axi-symmetric model of the barrel of a handgun. Borland International Quattro Pro spreadsheet program along with Runge-Kutta and Newmark numerical integration techniques have been employed to optimally design the recoil system of a handgun. Also, the use of Quattro Pro for constructing the contour plots of temperature in a Very Large Scale Integrated (VLSI) chip and the IBM 3081 TCM cold plate are demonstrated. Finally, the built-in Error and Bessel functions in Microsoft Excel have been used to find temperature distribution in a semi-infinite and cylindrical objects.
MS Windows GUI for Linear Spring Design
Authors: Yip T. Gary , Patel Ajay
Published: March 2021

Two versions of a Windows-based linear spring design software have been developed. They are presented here to illustrate how graphical user interfaces can enhance the flow of control of a design process. The software also demonstrates that optimized usage of screen space can make an expert system based design software more intuitive. The two software presented here illustrate that well conceived GUI’s can improve the productivity of a design engineer.
Comparison of a Nonlinear k-ε Turbulence Closure Model With Stress Transport Models
Authors: Sharif Muhammad A. R. , Wong Yat-Kit E.
Published: March 2021

The performance of a nonlinear k-ϵ turbulence closure model (NKEM), in the prediction of isothermal incompressible turbulent flows, is compared with that of the stress transport models such as the differential Reynolds stress transport model (RSTM) and the algebraic stress transport model (ASTM). Fully developed turbulent pipe flow and confined turbulent swirling flow with a central non-swirling jet are numerically predicted using the Marker and Cell (MAC) finite difference method. Comparison of the prediction with the experiment show that all three models perform reasonably well for the pipe flow problem. For the swirling flow problem, the RSTM and ASTM is superior than the NKEM. RSTM and ASTM provide good agreement with measured mean velocity profiles. However, the turbulent stresses are over- or under-predicted. NKEM performs badly in prediction of mean velocity as well as the turbulent stresses.
A Design Process Model With Multiple Design Object Models
Authors: Yoshioka Masaharu , Nakamura Masahiko , Tomiyama Tetsuo , Yoshikawa Hiroyuki
Published: March 2021

An intelligent CAD system is not merely a set of intelligent design tools, but rather it must be an intelligent, integrated design environment. This requests it must be equipped with a large scale knowledge base in which design knowledge is intensively and systematically stored. To do so, design knowledge must be systematically formalized, made computable, and organized. The present paper investigates fundamental issues of systematization of design knowledge. Design knowledge has two categories; i.e., design object knowledge and design process knowledge. In our previous reports, we have formalized a computable design process model to represent design process knowledge and the concept of metamodel dealing with multiple design object models. This paper proposes a framework to achieve harmonized combination of these two. In this framework, the computable design process model navigates the metamodel mechanism to generate and modify models of the design object. We describe a prototype system and illustrate an example of ship design.
Life-Cycle Clumping of Product Designs for Ownership and Retirement
Authors: Marks Matthew D. , Eubanks Charles F. , Ishii Kos
Published: March 2021

This paper describes a design strategy for mechanical systems called clumping and its effect on product value during the ownership and retirement phases of its life-cycle. A “clump” is a collection of components and/or subassemblies that share a physical relationship and some common characteristic based upon user intent. Clumping for product ownership values, i.e. reliability and serviceability, aims to increase component accessibility. Clumping for product retirement issues, i.e. reuse, recycling, and disposal, seeks to form aggregations of components for material compatibility, thus decreasing disassembly cost. This paper gives a detailed description of life-cycle ownership and retirement assessment methods and how they can be adapted into an existing computer-based design aid. A refrigerator in-door ice dispenser serves as an illustrative example.
Consideration of Failure Diagnosis in Conceptual Design of Mechanical Systems
Authors: Ruff David N. , Paasch Robert K.
Published: March 2021

A methodology for improving quality and reducing life cycle costs of mechanical systems is described. The principle concept is that a system can be designed, in the conceptual stages, to be easier to diagnose for failures. To perform this, functional decomposition and form to function mapping are utilized both as a model of design and to demonstrate the relation of diagnosis to design. Design guidelines from other disciplines of engineering and concurrent engineering principles are applied to enhance the concept. The affects of the different elements of concurrent engineering on each other are explored. Of the elements of concurrent engineering, design for manufacturability affects the others the greatest. Design for manufacturability principles impact the size of field replaceable units and can improve the ease of failure diagnosis of a system. For a hypothetical case, form to function mapping that would create a difficult to diagnose system is redesigned to reduce the difficulty of failure diagnosis. Further, three diagnosability metrics are developed and four hypothetical conceptual designs are evaluated for diagnosability and compared The area of design for diagnosis offers promise in improving system quality and reducing life cycle cost; research is continuing to refine and integrate the procedures with other components of the concurrent engineering design process.
Iterative Overlapping: Accelerating Product Development by Preliminary Information Exchange
Authors: Krishnan Viswanathan , Eppinger Steven D. , Whitney Daniel E.
Published: March 2021

In this paper, we consider the problem of accelerating commercial product development by overlapping adjacent functions. We formulate an approach, called iterative overlapping, in which downstream development activities start with preliminary design information and incorporate upstream design changes in subsequent iterations. In the absence of careful control, iterative overlapping could cause excessive downstream rework and result in an increase in development time. We develop models of iterations and design change to help decide when upstream design information should be committed for downstream iterations. When applied to an automobile door panel development process at a US automaker, the models suggest improvements that would reduce development time by 27%.
On the Parametrically Excited Response of the Quadratically Nonlinear Model of a Rotating Ring on an Elastic Hub
Authors: Zadoks Rick I. , Krousgrill Charles M.
Published: March 2021

As a first approximation, a steel-belted radial tire can be modeled as a one dimensional rotating ring connected elastically to a moving hub. This ring can be modeled mathematically using a set of three nonlinear partial differential equations, where the three degrees of freedom are a radial displacement, a tangential displacement and a section rotation. In this study, only quadratic geometric nonlinearities are considered. The system is excited by a temporally harmonic point load f^(t) and a temporally harmonic hub motion z^(t) that have the same harmonic frequency. The point load f^(t) appears in the equations of motion as a single in-homogeneous term, while the hub motion z^(t) appears in inhomogeneous and parametric excitation terms. To simplifying the ensuing analysis, the rotation rate of the hub is assumed to be constant.

The partial differential equations of motion are reduced to a set of four second-order ordinary differential equations by using two linear normal modes to approximate the spatial distribution of the displacements. A region of the parameter space, as defined by ranges of values of the excitation amplitude z and the excitation frequency ω (or detuning parameter σ), is identified, from a Strutt diagram, where the parametric excitation is expected to be dominant. In this region σ is varied to locate a secondary Hopf bifurcation that leads to a set of complex steady-state quasi-periodic solutions. These solutions contain two families of frequency components where the fundamental frequencies of these families are non-commensurate, and they are characterized by Poincaré sections with closed or nearly closed “orbits” as opposed to the distinct points displayed by periodic responses and the strange attractor sections displayed by chaotic solutions.
The Doctrine of Manifest Danger and its Relationship to Reliability, Preventive Maintenance and Fail-Safe Design
Authors: Barnett Ralph L.
Published: March 2021

“Dust thou art, and unto dust shalt thou return.”1 Man has made no observations that would challenge this notion from the Bible and certainly safeguarding systems fall into lockstep. Safety technology has responded to the reality of eventual degradation using four general approaches: reliability design, preventive maintenance, fail-safe design and danger manifestation. The optimum implementation of these approaches will still not eliminate accidents; indeed, no work of manor nature is or can be danger free. Nevertheless, these sophisticated approaches are capable of producing ever-increasing levels of safety, albeit, with attendant ever-increasing cost. It is at once unfortunate and unacceptable that common law2 is not equally sophisticated in dealing with the inevitable failure of safeguarding systems over time.

This paper introduces The Doctrine of Manifest Danger which is defined as a design concept using direct cues or indicator devices to communicate to the community of users that the safety of a system has been compromised before injuries occur. Furthermore, the paper addresses a related legal issue by distinguishing between proximate cause and cause of action.
A Statistical Adaptable Distribution Function Model for Low Probabilities of Failure
Authors: Bhonsle Suryaji R. , Thompson Paul
Published: March 2021

Weibull, log normal, and some other Distribution function models (D.F.M.) have a tendency to deviate from experimental results. This deviation, either exceedingly conservative or nonconservative, is amplified at low probabilities of failure. To remedy such problems a new D.F.M. is derived. It is then used to predict low probabilities of failure. The predictions are consistent with experimental data and are not too conservative or too nonconservative.
Determination of Residual Stress Distribution in Sensitive and Insensitive Materials
Authors: Jahanian Shahriar
Published: March 2021

One of the important factors to be considered in design is the residual stress distribution in the component. The positive or negative effect of these stresses plays an important role in the life of components. The unexpected failure of the components latter determined to be attributed to the residual stress distribution is not uncommon. Often in the design of nuclear reactor coolant system and components, the level of residual and transient thermal stress distribution is an important factor to be considered. Obviously the level of these stresses depend on the fact that if the material is sensitive (material with temperature dependent properties or insensitive. In this paper an infinite hollow cylinder is considered as an example. A theoretical study, which predict the thermoelastoplastic and residual stress distribution is presented. A quasi static and uncoupled thermoelastoplastic analysis based on incremental theory of plasticity is developed and a numerical procedure for successive approximation is presented. The problem is solved for both case of sensitive and insensitive material. The level of residual and thermoelastoplastic stress for both cases are compared and discussed in detail.
On the Fundamental Issues in Nonstationary Dynamics and Chaos
Authors: Evan-Iwanowski Ross M. , Lu Chu Ho , Ostiguy Germain L.
Published: March 2021

In nonstationary (NS) systems some control parameters (CPs) have the following forms: CP(t) = CP0 + ψ(t), where CP0 = const, and ψ(t) are arbitrary functions of t. Other arbitrary functions which play a pivotal role in the NS systems are the parameter functions ϕ(CP) = 0, CP = {CP1, CP2...CPn}. While the functions ψ(t) determine the time directions of the NS dynamical behavior, the functions ϕ(CP) = 0 determine the paths for the CPs to follow.

The NS processes are permanently transient due to the functions ψ(t) and/or ϕ(CP) = 0, and for that reason, they can be extremely complex. Clearly then, it is essential to address the fundamental problems of cohesion and definitness of these processes.

Using select examples, these issues have been studied in this presentation and have been resolved in positive. Specifically, the following have been demonstrated:

(1) convergence (definitivness) of the NS logistic map and the softening Duffing oscillator to an NS limit motion

(2) the appearance of a sequence of similar attractors for different NS bifurcations

(3) the effects of different parameter paths, ϕ(CP) = 0, in the period doubling region of the Duffing oscillator

(4) the effects of linear and cyclic paths in transition through the Ueda bifurcation regions. The results obtained show considerable complexity of the NS dynamic and chaotic responses

(5) for exponential ψ(t), the Lorenz “weather” three-term model exhibit a periodic “window” in the chaotic range for an extended value of t.

(6) the effects of different ψ(t) in the typical codimension one bifurcations

(7) the ST chaos may be created or annihilated by injection of NS inputs

(8) an efficient and fast stabilization, i.e., reduction of ST vibration to near the static equilibrium in a short time, can be accomplished by NS changes of the parameters of the system.
A Constructive Method for Locating Periodic Solutions of Linear and Nonlinear Systems
Authors: Torok J. S.
Published: March 2021

In this paper, an efficient algorithm is developed for the identification of stable steady-state solutions to periodically-forced linear and nonlinear dynamical systems. The developed method is based on mapping techniques introduced by Henri Poincare and the theory of one-parameter transformation groups. The algorithm successfully identifies initial conditions which give rise to strictly periodic orbits.
Elastically Mounted Body in Cross Flow With an Attached Pendulum
Authors: Tondl Aleš
Published: March 2021

A pendulum is attached to an elastically mounted body in cross flow. The body is excited due to the action of vortex shedding. The stability of the semi-trivial solution (representing the vibration of the body with the non-oscillating pendulum) is investigated. It is proved that a certain interval of the vortex shedding frequency can exist where the semi-trivial solution representing the vertical vibration of the body is unstable. The body vibration is the source of parametric excitation of the pendulum resulting in autoparametric resonance.
A Study of the Nonlinear Dynamics of a Flap-Lag Rotor Model in Forward Flight
Authors: Putko Michele M. , Flowers George T.
Published: March 2021

For the purposes of stability analyses, it is necessary to describe the dynamic equilibrium state of a rotor blade in forward flight in terms of a Fourier series. Typically, this is assumed to consist of constant and sinusoidal terms that are integer multiples of the rotor speed. Such an approach neglects potentially important dynamics associated with subsynchronous, supersynchronous, and aperiodic responses. The current work investigates the occurrence of such behavior and discusses some conditions where it may be important. Simulation studies are conducted using a simplified nonlinear rotor blade model in forward flight. This model consists of a rigid blade with effective hinges at the root to simulate a hingeless rotor blade. Quasi-steady linear strip theory is used to provide aerodynamic forcing in the model. The nonlinear terms arise from geometrical effects in the structural and aerodynamic modeling procedure. The resulting system of equations is studied using direct numerical integration and harmonic balancing. Nonsynchronous and aperiodic responses are observed for several realistic parameter configurations.
A Study of Optimal Equivalent Characteristics of Insole Materials
Authors: Shiue Yeu-Sheng , Tan Teong E.
Published: March 2021

In this preliminary study, a methodology was illustrated in the determination of the characteristics of an insole material by modeling it as an equivalent mass-spring-damper system.

The experimental deceleration-time data obtained from specimens of twenty commercial formulations of shoe insole materials were utilized to verify a suitable mathematical model that could be used as an adequate representation of a shoe insole material. The suitable equivalent model was used to search for parameter values that would yield the best cushioning effect. For this study, two linear and two nonlinear mass-spring-damper systems were investigated. The two models with linear spring and damping elements were found to be unsuitable representations of the tested materials. The nonlinear six-parameter model was found to perform only marginally better than the nonlinear four-parameter model. Therefore, the simpler four-parameter model was selected for optimization study.

In the optimization study, multiple local minima were found with the nonlinear four-parameter model using an unbounded variable optimization routine. However, when lower and upper bounds were specified for the four parameters, two of the parameters consistently approached the lower bound values, one parameter approached the upper bound value, and the remaining parameter settled at a value close to the lower bound. Global minimum was unattainable in the present study.
Experimental Study of Chaos in a Flexible Parametrically Excited Beam
Authors: Baker C. P. , Genaux M. E. , Burton T. D.
Published: March 2021

Nonlinear vibrations in an axially driven limber cantilever beam are studied experimentally to determine whether the observed aperiodic motions are chaotic, and to find the attractor dimension. Using the method of delays and time series calculations, the largest Lyapunov exponent is found to be positive, indicating that the aperiodic motions are chaotic. The correlation and embedding dimensions are computed; a phase space dimension in the range of 5–7 is found for the chaotic attractor. The system is also studied analytically, using a truncated Galerkin reduction of the planar equation of motion. It is found that this analytical approach does model the near-harmonic periodic motions of this system; however, the chaotic motions and chaotic transitions are not predicted. The model does exhibit interesting chaotic responses for non-physical values of the driving parameters.
Stability of the Second Order Difference Equation With Time-Varying Parameter
Authors: Tanaka Toshiyuki , Sato Chikara
Published: March 2021

This paper deals with the stability of the second order difference equation possessing periodic parameter, which characterizes discrete periodic system. Discrete periodic system corresponding to Mathieu equation is expressed as second order difference equation with small parameter ε in the time-varying term. This parameter ε plays an important role in stability. For the fundamental equation without damping, stability boundary curves are analytically obtained with respect to parameters in the equation by using McLachlan’s method, which is based on Floquet’s theory and perturbation method. The boundary curves are computed by pursuing periodic solutions on the boundaries and letting secular term zero. The boundary curves are expressed as the power series of ε. When periodic parameter consists of even function of Fourier series, stability boundary curves are obtained. For the fundamental equation with damping, stability criterion is shown in the neighbor of important resonant points. This criterion is obtained by computing points on the boundary curves.
The Response of Nonlinear Systems to Modulated High-Frequency Input
Authors: Nayfeh S. A. , Nayfeh A. H.
Published: March 2021

We study the response of a single-degree-of-freedom system with cubic nonlinearities to an amplitude-modulated excitation whose carrier frequency is much higher than the natural frequency of the system. The only restriction on the amplitude modulation is that it contain frequencies much lower than the carrier frequency of the excitation. We apply the theory to different types of amplitude modulation and find that resonant excitation of the system may occur under some conditions.
Nonstationary Motions in Stationary Vibrating Systems: A Discussion
Authors: Szemplińska-Stupnicka W.
Published: March 2021

The paper presents a discussion on relationships between the concepts of nonstationary, random and chaotic motion. The discussion is based on computer simulation results and the approximate theory of nonlinear oscillations. Two forced oscillators are considered: the dissipative unsymmetric oscillator and the self-excited symmetric system. It is concluded that chaotic component of motion can be interpreted as a sort of nonstationary “free vibration” with randomly modulated amplitude and phase. The proposed approximate model of chaos seems to blur a clear distinction between the traditional concepts of stochastic and deterministic, and between stationary and nonstationary system as well.
Modeling and Optimization of Dissipative Properties of Industrial Articulated Manipulators
Authors: Dakev Nickolay V.
Published: March 2021

A mathematical model describing elastic and dissipative properties of manipulator links and joints is considered. An articulated manipulator is regarded as an open kinematic chain of absolutely rigid arms connected by flexible joints. Free and forced vibrations around goal manipulator configurations are studied. Friction forces are supposed to be applied to the manipulator hinges. They are described by the help of generalized dissipative function. According to this model the possibilities for damping the free and forced vibrations of industrial articulated manipulators are studied. Some problems for defining the optimal friction laws with regard to new energy criteria are solved.

A global energy criterion depending on the total mechanical energy is proposed. It is proved that this functional doesn’t depend on the character of the transient oscillation process. A minimax problem is formulated and a computer oriented method for its solving is developed. Another energy criterion is connected with maximizing the average power dissipated for one period of forced oscillations. A general algorithm for defining the corresponding optimal periodic damp laws is worked out. The results obtained can be directly used for optimal passive and active damping of the vibrations of industrial manipulators by realizing of the corresponding friction laws.