An Investigation Into the Design of Hollow Accumulator Rolls Using Finite Element Analysis

Accumulator systems consist of a series of accumulator rolls, arranged either vertically or horizontally, used in many sheet processing lines for the purpose of storing up strip. Literature on roll design for this particular type of roll is scarce. Much of the present design theory is based on a static analysis assuming the entire contact load from the strip is uniformly distributed over the roll. A previous paper done on this subject focused on modeling the roll using finite element analysis (FEA) assuming this uniform pressure load on the roll. The purpose of this work was to incorporate non-linear contact elements between the strip and the roll body in a finite element analysis. This would allow the software to distribute the load from the strip to the roll, taking into account friction and contact losses. Once accomplished, this load was placed on various roll design configurations, of which included variation in the number of roll stiffeners and the thickness of the roll body and the end plates. These results were also compared to the previous uniform pressure FEA in order to assess the validity of the uniform pressure assumption. Based on these results, a roll design methodology is presented.

Influence of Coating Layer to Reduce Thermal Stresses in Cylindrically Formed Metal Matrix Composites

In this study, the use of coating layers is investigated to reduce thermal stresses in the metal matrix composites which have a mismatch in coefficients of thermal expansions in fiber and matrix components. The thermoelastic solutions are obtained based on a three-cylinder model. It is shown that the effectiveness of the layer can be defined by the product of its coefficient of thermal expansion and thickness. Consequently, a compensating layer with a sufficiently high coefficient of thermal expansion can reduce the thermal stresses in the metal matrix. The study is based on a concentric three cylinder model isolating individual steel fibers surrounded with a coating layer and an aluminum matrix layer. Only monotonic cooling is studied.

Elasto-Plastic Behavior of Thermoplastic Matrix Roller Chain Link Plates Reinforced With Steel Fibers

The elastic and elasto-plastic stress analysis of thermoplastic matrix roller chain link plates reinforced with steel fibers is performed by using Finite Elements Analysis (FEA). A two-dimensional finite element computer program is developed for elasto-plastic stress analysis. Isoparametric quadratic element with four nodes is used with Lagrange polynomial as an interpolation function. The results of elastic and elasto-plastic finite element stress analysis by using the computer program prepared, are compared with experimental, (photoelastic) results. The spreads of the plastic zones due to the external load applied on the pin-hole of the plate and variations of the residual stresses are determined in different orientation angles and loads. It is shown that the geometry of the link plates can be designed to decrease the stress concentrations. Furthermore, it is shown that the tensile load limit of the roller chain link plate is extended by the residual stresses.

Agile Automation Control Systems: The Hansford Assembly Flex Project

This paper reviews the Hansford Assembly Flex project recently conducted at RPI. Assembly Flex is a modular automation assembly system in the truest sense. It most cases it can be reconfigured (re-tooled) in under 20 minutes and go from building water pumps to car stereos. Much of this flexibility stems from its unique software control system developed by the authors and others.

State Library Materials Handling System Design: Part II

This paper (part two of two) discusses the concepts generated by the Center for Automation Technologies, Rensselaer Polytechnic Institute, for an automation system for the New York State Talking Book and Braille Library (TBBL). It describes the last several module concepts in the system, designed to assist the TBBL staff in the processing of “talking books” (books on cassette), and discusses system simulations, and conclusions from this work. Part one discussed the assessment of needs, requirements, and process flow (all of which are summarized here), as well as the first several modules in the system. The primary purposes for this modular system are 1. To assist the TBBL in meeting increased throughput demands and 2. To reduce work-related injury claims. The modules are designed to work individually (as to allow the possibility of similar libraries in other states to purchase modules as desired), and facilitate incremental implementation toward a complete system (for maximized benefit). In this paper, the modules discussed are the latch closer, label remover, and the virtual turnaround shelves system.

Shakedown Analysis of a Finite Plate With Single Edge Notch Under Uniaxial Tension

In this paper, the shakedown load factor for a finite rectangular plate with a single edge notch at its mid-length is evaluated by a number of numerical and analytical techniques. These techniques include full elasto-plastic finite element solution coupled with line search technique and an iterative elastic technique known as the elastic compensation method which relies on successive reduction of elastic modulus in regions where elastic stresses exceed yield strength. In addition, an analytical technique proposed recently in the literature, which relies on a gradient optimization technique is employed. The shakedown load factor values obtained through different solution techniques are compared. The comparison showed discrepancies between literature solutions and the solutions presented herein. The reasons behind this discrepancy are scrutinized and certain recommendations are made to ensure validity of shakedown solutions.

Development of Impact Resistant Optical Pick-Up for Portable Disk Products

Concerning the development of portable optical disk products, higher impact resistant of the optical pick-up is required. Conventionally, cut and try measures, mainly based on experiment were applied to these problems, and it took much time and cost. Therefore, we developed this drop impact analysis of the optical pick-up based on the Finite Element Method (FEM) and clarified the failure mechanism of the suspension wire breaking with drop impact. With this analysis method, we also developed a new optical pick-up with a curved suspension wire, and realized much higher impact resistance.

Geometric Non-Linear Influence of a Payload Fairing on Dynamic Displacement Response

Finite element method using three noded plate and shell element and 3D beam element in conjunction with mode superposition method is used for studying the large dynamic displacement response of a typical payload fairing due to separation impulse. Incremental technique is used for solving the geometric non-linear problem. Linear formulations are assumed and a step-by-step analysis is performed on the deformed state of each previous time step. The geometry is updated and the stiffness matrix recomputed after every finite time step and the eigenvalue analysis repeated.

Modeling the Ratcheting Phenomenon in an Austenitic Steel at Room Temperature

This paper describes the cyclic accumulative plastic strain in a polycrystalline material when subjected to loading conditions promoting ratcheting behavior. For this purpose, a unified viscoplastic constitutive model based on non-linear kinematic hardening formulation is implemented. Identification of the model parameters was carried out using an experimental program that included monotonic, cyclic and relaxation testing. Simulation of the material response using the proposed model is compared with experimental results for the same loading. This comparison is used to evaluate the model validity.

Mixed Mode Fatigue Fracture Criteria for the Plates With an Inclined Semi-Elliptical Crack

The behaviour of fatigue crack propagation of rectangular steel plates, each consisting of an inclined semi-elliptical crack, subjected to axial loading was investigated both experimentally and theoretically. The inclined angle of the crack with respect to the axis of loading varied between 0° and 90°. In the present investigation, the Von Mises yield criterion was applied to define the core region, instead of a core region with a constant distance r from the crack tip. Based on Von Mises elasto-plastic boundary, the two commonly used fracture criteria, the maximum tensile stress and the minimum strain energy density criteria, were modified. The results obtained using the two improved fracture criteria were compared with those obtained using the commonly used mixed mode fracture criteria and experimental results. A mixed mode fatigue crack criterion has been established based on the experimental data.