bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adaptivity and Mesh Generation in 2-D Finite Element Analysis
Authors: Almeida C. A. 
Published: March 2021

Abstract
A methodology for the automatic mesh generation of triangular and quadrilateral finite element discretizations for two-dimensional elasticity problems is proposed. The methodology is based on: i) an h-adaptive process with powerful mesh generator facilities capable of achieving meshes of specified density, ii) a general stress recovery technique developed for determining the element solutions at the nodes, and iii) an a posteriori error estimation. The h-adaptive process used is based on a complete mesh regeneration procedure which is guided by specified mesh requirements such as geometry definitions, boundary conditions, and space node functions to achieve an optimal refinement. This optimality condition is, as established by Zienkiewicz and Zhu, the mesh refinement with the least number of elements that yields a uniform strain energy norm error distribution in all elements. In the stress recovery process, the nodal values are assumed to belong to a polynomial expansion of the same complete order in the interpolation function basis used, which is valid over all elements adjoining a particular node. A least-squares fit of superconvergent sampling points existing in the path is used to obtain the recovered nodal point parameters for each element. These parameters are averaged to all elements adjoining the node of interest. The technique is simple and cost-effective, and the recovered nodal values of derivatives are superconvergent at the Gauss integration points, which are used as sampling points for quadrilateral elements. This condition is also achieved when centroid and mid-side points are used for triangular elements. The error estimation is done evaluating differences between the post-processed stress gradients and those from the finite element solutions. The energy error norm associated with stress field differences and the finite element predicted strain energy gives an effective error estimate which can be used for comparison with the process tolerance. The technique has been implemented and allows for a fully automatic numerical analysis under a specified global energy error norm. Numerical tests conducted with various planar element formulations illustrate that the proposed technique converges in fewer steps than with previous methods of adaptive mesh refinement.
Computer Simulations for Frontal Impact
Authors: Doong Jiamaw , Cheng James C. 
Published: March 2021

Abstract
Vehicle crash performance is different for various testing configurations. The current NCAP fixed rigid barrier frontal impact test and FMVSS regulations have significantly improved occupant safety during a frontal crash. However in order to better represent and reduce fatal injuries in real world frontal impacts, several new frontal impact test configurations are being proposed and studied.
This paper compares four different frontal impact configurations with 35 mph impact speed, in terms of finite element crash simulation. The four configurations are 1) 90 degree fixed rigid barrier, 2) 50% offset rigid barrier, 3) 30 degree angular fixed rigid barrier, without anti-slide device, and 4) 30 degree angular fixed rigid barrier, with anti-slide device. This advanced computer simulation technology is now widely used in the auto industry and, in terms of the efficiency, timing and cost, it is the only tool powerful enough to face the technical challenges in future vehicle design.
The comparison is made from a structural point of view. Impact force, deceleration, deformation, and dash/toeboard intrusion are compared. Based on the performance of a given vehicle structure, a qualitative assessment of occupant behavior/injury can be drawn. The general relationship between occupant behavior and vehicle structural response, during a crash event, is well known, e.g. lower vehicle deceleration and less deformation of the passenger compartment will produce better occupant injury performance. The results of this study might be used as a reference for vehicle front end design or potential rulemaking for frontal impact tests.
Three-Dimensional Flowfield Prediction
Authors: Lin T.-K. , Lilley D. G. 
Published: March 2021

Abstract
The development, use and application of a three-dimensional fluid flow computer code is described. The code runs on microcomputers with effective 3-D perspective color graphic displays of the results. The present version of the code retains several simplifications, uses a uniform rectangular grid system, and runs on microcomputers, thus providing a powerful and economical software capability. Equations are solved for the fully 3-D problem, including pressure, three velocity components and species mass fractions. The simulation is a finite difference time-marching procedure using an explicit formulation of the conservation equations, followed at each step by an iteration updating pressures and velocities so as to impose the continuity requirement. The present paper documents the problem, describes briefly its simulation, theory and assumptions, and gives results showing an application of the code to co-flowing round jet mixing.
Examination of a “Map-Based” Approach to Modeling Steady State Heat Pump Performance With Variable Air Flow Rates
Authors: Mawasha P. , Rooke S. P. , Gross R. 
Published: March 2021

Abstract
Performance map-based modeling has been commonly employed for the rapid prediction of air conditioning and heat pump steady state performance. This approach requires that performance characteristics of the compressor and heat exchangers can be expressed in the form of simple algebraic functions. The growth of microprocessor based control, particularly in residential systems, has led to more frequent off-design operation. This study explores the ability of the map-based modeling approach to predict off-design operating performance of a single air-source heat pump operating in the cooling mode. Off-design conditions were simulated by varying the evaporator air flow rate over a wide range. Performance predictions are compared with the predictions of a more rigorous heat pump simulation program which utilizes heat transfer correlations for the heat exchangers rather than performance maps. A PC math package was used to generate results for the map-based model, while a Fortran compiler was used to generate results for the more rigorous model. The benefits of the map-based approach in predicting system performance are presented and discussed.
A New Method and Device for Temperature Measurement Using One-Dimensional Heat Equation
Authors: Damean Nicolae A. 
Published: March 2021

Abstract
A new method and device for temperature measurement are presented. The method reduces the measurement of the unknown temperature to the solving of an optimal control problem, using a numerical computer. The device consists of a hardware part including some conventional transducers and a software one.
The problem of temperature measurement, according to this method, is mathematically modelled by means of the one-dimensional heat equation, describing the heat transfer through the device.
The principal component of the device is a rod. The variation of the temperature which is produced near one end of the rod is determined using some temperature measurements in the other end of the rod, the mathematical model and a type of gradient algorithm.
This device works as an attenuator of high temperatures and as an amplifier of low temperatures.
Development of a Prototype Design Process Recorder Based on Hypergraphs
Authors: Hirose Atsushi , Cannon David M. , Leifer Larry J. 
Published: March 2021

Abstract
We describe a design process recording method and a prototype implementation. They are being developed from data on several design projects, including an in-depth study of a 6-month long design effort, itself part of a multi-year aerospace research and design project. The work is also influenced by the larger context of other design research projects at Stanford. The recording method focuses on information generated in early stages of design that is at the same time easiest to capture and most useful to designers and engineers downstream. It does this by being based primarily on a design process model intended to reflect a designer’s point of view, and by taking advantage of practices that designers currently find useful. The method builds on the concept of an electronic notebook that has been described previously (Lakin et al., 1989). The record consists of connected pieces of information about the various concepts, notes, and documents that are central to an evolving design. We call the framework for the record a hypergraph: ‘graph’ because of its node-arc structure, and ‘hyper’ because it spans several types of information that are created during design work. To effectively convey the record’s contents to a downstream user, we propose a design story-teller style: the system’s response to a query takes the form of a storyboard of notes about related design episodes.
Physical Synthesis in Case-Based Design
Authors: Michelena Nestor , Sycara Katia 
Published: March 2021

Abstract
Common design practices rely heavily on searching and studying of prior designs, patents, past design rationale, standards and new product announcements. An important step toward automating these activities is the creation of repositories of design information indexed by abstract attributes in addition to low-level structural descriptions. By reusing prior designs or their components an engineer can save design time, by leveraging off previous worked-out solutions, and avoid repeating past mistakes, by accessing information on manufacturing or field failures linked to the retrieved design. Under the case-based design paradigm, an engineer combines parts of different design cases to synthesize a device that satisfies a useful need. Physical synthesis entails taking into account possible interactions between components and sub-assemblies as well as reasoning about the dynamics of the system. In this paper we present a methodology for physical synthesis of design cases and components retrieved by a case-based design tool. Connecting elements for the design cases and components are retrieved from a casebase of connections. Indexing of these connections is based on the mobility restrictions that they impose on the connected parts. The information necessary to accomplish this task is still of a high-level nature, namely, the topology of the artifact and its abstract behavior specification.
Automatic Generation of 3-D Solid Models From Orthographic Projections
Authors: Saha K. , Gurumoorthy B. 
Published: March 2021

Abstract
This paper describes an algorithm to generate 3-D solid models of objects from their orthographic projections. This approach is entirely different from the earlier bottom-up approaches. Instead of generating the 3-D vertices, edges and faces sequentially, this approach considers an object to be the boolean combination of a number of elementary objects, which are 2.5D solids. The elementary objects are formed by decomposing a given view into loops and sweeping each loop perpendicular to the direction of projection. This algorithm can handle objects whose projections have curved edge(s) in one view of the orthographic projection. It is believed that proper extension of this algorithm can handle sectional views and multiple views, which has not been addressed in the bottom-up approach.
Goal-Directed Geometry: Beyond Parametric and Variational Geometry CAD Technologies
Authors: Rosen David W. , Chen Wei , Coulter Stewart , Vadde Srinivas 
Published: March 2021

Abstract
Improved computer-aided design tools can significantly impact designer productivity. The ability to formulate and solve “What if” questions is critical in early design stages. In this paper, a new computational framework for preliminary design, called Goal-Directed Geometry, is presented that provides such an exploratory environment for early stages. Tools for parametric geometry, variational modeling, and feature-based design are combined with a multiobjective optimization code to provide robust support for parametric design problems, where parameter values are desired that best meet a set of goals and constraints. Geometric and engineering models of a design are combined into a multiobjective optimization formulation called a Compromise Decision Support Problem, which can be solved by the existing package DSIDES (Decision Support In the Design of Engineering Systems). A prototype CAD system is under development that integrates DSIDES, a geometric modeler, and variational, parametric, and feature capabilities. The system aids a designer in evaluating competing alternatives, common during preliminary design, and in answering “What if” types of questions. Two examples illustrate the use of Goal-Directed Geometry in formulating and solving parametric design problems involving engineering and geometric constraints and goals.
Fatigue Life Simulation for Reliable Thick-Walled Cylinder Design
Authors: Eggert R. J. 
Published: March 2021

Abstract
Primary considerations for hydraulic cylinder and piston design include loading, geometry and material properties. However, variations in as-manufactured dimensions, as-processed material properties, and actual pressure histories propagate through the piston-seal-cylinder system often resulting in intolerable behaviors.
Variations are evaluated using design variation simulation, namely the Monte Carlo simulation technique and available statistical information, to evaluate a high-pressure piston-seal-cylinder system for servo-hydraulic fatigue testing experiments.
The numerical results indicate that the fatigue life as measured by number of cycles to failure, has a significant 140.8% coefficient of variation and 57.2% reliability for nominal design values. When the coefficients of variation of the input variables are maintained below 1%, the fatigue life coefficient of variation is approximately 13.3% and the reliability is 99.06%.
A Domain Decomposition Method for Large Scale Structural Optimization
Authors: Spengemann Frank , Booz Walter 
Published: March 2021

Abstract
A domain decompostion method for large scale structural optimization is proposed. A block diagonal preconditioning scheme is used to partition the structural model into a number of smaller subsystems and to approximate the state variables. In this two level approach the optimization is done on the lower level, on the upper level the coordination of the subsystems is performed by approximating the multipliers of the optimality criteria.
A Simulated Annealing-Based Approach to Three Dimensional Component Packing
Authors: Szykman Simon , Cagan Jonathan 
Published: March 2021

Abstract
This paper introduces a computational approach to three dimensional component layout that employs simulated annealing to generate optimal solutions. Simulated annealing has been used extensively for two dimensional layout of VLSI circuits; this research extends techniques developed for two dimensional layout optimization to three dimensional problems which are more representative of mechanical engineering applications. In many of these applications, miniaturization trends increase the need to achieve higher packing density and fit components into smaller containers. This research addresses the three dimensional packing problem, which is a subset of the general component layout problem, as a framework in which to solve general layout problems.
Recycling Oriented Fasteners: A Critical Evaluation of VDI 2243’s Selection Table
Authors: VerGow Zachary , Bras Bert 
Published: March 2021

Abstract
A growing concern about the environment, and especially about waste and landfill, has spurred research into the design of more environmentally benign products. A dramatic reduction in environmental impact can be made by recycling. A critical issue in recycling is the separation of joints in the disassembly process. In product recycling (also referred to as reuse) non-destructive disassembly is desired, whereas in material recycling destructive disassembly is allowed (e.g., shredding). This has an impact on the selection of fasteners. In this paper, we provide an overview of the issues involved and specifically we evaluate the selection of fasteners in the context of product recycling, material recycling, and technical aspects as documented in the new German standard VDI 2243, “Designing Technical Products for Ease of Recycling – Fundamentals and Rules for Design”. The results of this evaluation provide insight in future areas of research and fastener selection models for life cycle design.
Optimization of Multibody Systems Using Sequential Linear Programming
Authors: Etman L. F. P. , Thijssen E. J. R. W. , Schoofs A. J. G. , van Campen D. H. 
Published: March 2021

Abstract
Design optimization is far less developed for multibody analysis than for structural analysis. However, multibody design problems can be solved by optimization strategies applied in structural analysis. To illustrate this, a design optimization tool has been developed for a multibody analysis software package. It is based on a linear approximation concept. An optimization process results that consists of a sequence of linear programming problems. The design optimization tool has been successfully tested for three multibody design examples.
Application of Topological Optimization Techniques to Structural Crashworthiness
Authors: Mayer Robert R. , Kikuchl Noboru , Scott Richard A. 
Published: March 2021

Abstract
The topological optimization of components to maximize crash energy absorption for a given volume is considered. The crash analysis is performed using a DYNA3D finite element analysis. The original solid elements are replaced by ones with holes, the hole size being characterized by a so-called density (measure of the reduced volume). A homogenization method is used to find elastic moduli as a function of this density. Simpler approximations were developed to find plastic moduli and yield stress as functions of density.
Optimality criteria were derived from an optimization statement using densities as the design variables. A resizing algorithm was constructed so that the optimality criteria are approximately satisfied. A novel feature is the introduction of an objective function based on strain energies weighted at specified times. Each different choice of weighting factors leads to a different structure, allowing a range of design possibilities to be explored.
The method was applied to an automotive body rear rail. The original design and a new design of equal volume with holes were compared for energy absorption.
Circuit Analysis of Stephenson Chain Six-Bar Mechanisms
Authors: Davis Henry P. , Chase Thomas R. , Mirth John A. 
Published: March 2021

Abstract
A circuit quantifies a complete range of motion that a linkage can achieve without disassembly. A Stephenson linkage may have from one to six circuits. Current computer simulation packages are unable to define a circuit. Therefore, the simulations are limited to a small fraction of the total motion capability of a Stephenson linkage.
This paper presents a method to completely and unambiguously define all circuits of any pin-jointed Stephenson linkage. The method has been optimized for conversion to a computer algorithm. Once the circuits are known, any set of design positions can be matched to the circuits to determine if the mechanism can reach all positions without disassembly.
Closed Solution for the Elastic-Dynamic Behavior of an Industrial Press Feed Mechanism
Authors: Xu Tao , Lowen Gerard G. 
Published: March 2021

Abstract
A new linearized two degree of freedom model of an industrial press feed mechanism, containing an RSSR linkage, a bent coupler, an overrunning sprag clutch, a feed strip and a brake, is presented. By introducing a double cantilever model of the coupler with an assumed quarter sine shape function, simplifying certain terms of secondary importance and replacing the non-linear clutch spring by a linear torsional spring with a deflection dependent stiffness, it was possible to develop a set of two linear differential equations for the all important feed stroke, which could be fully solved in an analytic manner for the dynamic responses of the coupler strain and the clutch windup angle.
An Object-Oriented Differential-Geometric Approach to Spatial Mechanism Dynamics
Authors: Kecskeméthy Andrés G. 
Published: March 2021

Abstract
Described in this paper is a novel approach for the computer-generation of the dynamical equations of complex spatial mechanisms. A coordinate-free, intrinsic representation of the underlying equations is developed from well-known concepts of differential-geometry. The resulting objects are shown to be amenable to an object-oriented implementation based on the client-server paradigm, allowing for an open, intuitive and formalism-independent generation of corresponding computer models. We develop here primarly the theoretical foundations of the approach, referencing to applications in the literature.
Design of a Knee Mechanism for a Knee Disarticulation Prosthesis
Authors: Srinivasan Sujatha , Kramer Steven 
Published: March 2021

Abstract
A new knee mechanism has been designed which is a significant improvement over existing designs used in knee disarticulation (K/D) prostheses. These are prostheses used when the amputation is performed through the knee joint as opposed to amputation performed above the knee. The new four-bar mechanism has a more desirable locus of instant centers thereby improving the gait for K/D amputees. In this paper, the design process involving the kinematics is discussed. A prototype has been made and is currently undergoing testing with a prosthetist.
Design of a Walking Simulator
Authors: Bejune David , David John , Ouellette William , Zeilinski Brian , Chen Neal , Peura Brent , Norton Robert L. 
Published: March 2021

Abstract
A prototype of a simple, footwear-testing machine which mimics the physiologic motions and forces of walking in one plane has been designed, developed and tested. Eleven ROTC students were measured and filmed to obtain information on the kinematics of the lower limb and the dynamic forces exerted by their footwear on the ground while walking across a load plate. A machine was then designed which uses the coupler curve of a fourbar linkage to simulate the planar kinematics of the heel-strike and toe-off portions of walking. A standard-issue U. S. Army combat boot is attached to the fourbar linkage’s coupler link on a prosthetic foot such that the heel and sole are close to the moving centrode of the coupler. The ground plane is the fixed centrode. Thus their relative motion approximates pure rolling. The boot is “walked” against a force-plate which is loaded by an air cylinder. This force plate is pulled away during the walking “backstroke”. The dynamic forces of impact are measured by two force transducers. These measured forces simulate the vertical physiologic forces of walking and the kinematics provides realistic physiologic motions to the boot in a vertical plane.