Blast Alleviation of Cellular Sacrificial Cladding: A Nonlinear Plastic Shock Model

2016 ◽  
Vol 08 (04) ◽  
pp. 1650057 ◽  
Author(s):  
Yuanyuan Ding ◽  
Shilong Wang ◽  
Kai Zhao ◽  
Zhijun Zheng ◽  
Liming Yang ◽  
...  
Keyword(s):  
Critical Length ◽  
Element Model ◽  
Cover Plate ◽  
Shock Model ◽  
Regular Perturbation ◽  
Rigid Plastic ◽  
Perfectly Plastic ◽  
A Cell ◽  
Ph Shock ◽  
Hardening Parameter

The anti-blast behavior of cellular sacrificial cladding is investigated based on a continuum-based nonlinear plastic shock model. A rate-independent, rigid–plastic hardening (R-PH) model with two material parameters, namely the initial crushing stress and the strain hardening parameter, is employed to idealize the cellular material. The governing equation of the motion of cover plate is obtained and solved numerically with a fourth-order Runge–Kutta scheme. A comparison of the crushing percentage contours of sacrificial cladding based on the R-PH model and the rigid–perfectly plastic–locking (R-PP-L) model is carried out. Results transpire that the R-PP-L model is not accurate enough to evaluate the energy absorption. Dimensional analysis is employed to study the critical length of cellular sacrificial cladding and an empirical expression is determined by the controlling valuable method. An asymptotic solution is also obtained by applying the regular perturbation theory. Finally, the design criteria of cellular sacrificial cladding based on the R-PH shock model is verified by a cell-based finite element model.

Study on Cold Precision Forging of Non Straight Wall Cavity Piston

2011 ◽  
Vol 311-313 ◽  
pp. 2348-2352
Author(s):  
Ming Ming Ding ◽  
Ju Chen Xia ◽  
Lei Deng ◽  
Jun Song Jin
Keyword(s):  
Element Model ◽  
Cold Extrusion ◽  
Forming Process ◽  
Rigid Plastic ◽  
Precision Forging ◽  
Straight Wall ◽  
Cold Precision Forging ◽  
Overall Performance ◽  
Traditional Processing ◽  
Machine Processing

Brake piston is a huge demand non straight wall cavity part for the typical automotive industry; the traditional processing method is machine processing, or preforming by cold extrusion, and then machining. In this paper, the combined cold precision forging method of cold extrusion and spinning was proposed, which might improve the overall performance of parts and reduce costs. The rigid plastic finite element model of cold extrusion and spinning was established to simulate the forming process. The results showed that the combined cold precision forging method was available to manufacture non-straight wall cavity piston.

Elasto-Plastic Coupled Temperature-Displacement Finite Element Analysis of Two-Dimensional Rolling-Sliding Contact With a Translating Heat Source

1991 ◽  
Vol 113 (1) ◽  
pp. 93-101 ◽  
Author(s):  
S. M. Kulkarni ◽  
C. A. Rubin ◽  
G. T. Hahn
Keyword(s):  
Finite Element ◽  
Half Space ◽  
Plastic Material ◽  
Element Model ◽  
Rolling Contact ◽  
Two Dimensional ◽  
Element Analysis ◽  
Element Mesh ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic

The present paper, describes a transient translating elasto-plastic thermo-mechanical finite element model to study 2-D frictional rolling contact. Frictional two-dimensional contact is simulated by repeatedly translating a non-uniform thermo-mechanical distribution across the surface of an elasto-plastic half space. The half space is represented by a two dimensional finite element mesh with appropriate boundaries. Calculations are for an elastic-perfectly plastic material and the selected thermo-physical properties are assumed to be temperature independent. The paper presents temperature variations, stress and plastic strain distributions and deformations. Residual tensile stresses are observed. The magnitude and depth of these stresses depends on 1) the temperature gradients and 2) the magnitudes of the normal and tangential tractions.

Rigid-Plastic Impact of Single Angular Particles

2021 ◽  
Author(s):  
Sandeep Dhar
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Orientation Dependence ◽  
Particle Orientation ◽  
Rigid Plastic ◽  
Plastic Model ◽  
Model Predictions ◽  
Good Agreement ◽  
Angular Particles

The trajectory of an angular particle as it cuts a ductile target is, in general, complicated because of its dependence not only on particle shape, but also on particle orientation at the initial instant of impact. This orientation dependence has also made experimental measurement of impact parameters of single angular particles very difficult, resulting in a relatively small amount of available experimental data in the literature. The current work is focused on obtaining measurements of particle kinematics for comparison to rigid plastic model developed by Papini and Spelt. Fundamental mechanisms of material removal are identified, and measurements of rebound parameters and corresponding crater dimensions of single hardened steel particles launched against flat aluminium alloy targets are presented. Also a 2-D finite element model is developed and a dynamic analysis is performed to predict the erosion mechanism. Overall, a good agreement was found among the experimental results, rigid-plastic model predictions and finite element model predictions.

scholarly journals In silico stress fibre content affects peak strain in cytoplasm and nucleus but not in membrane for uniaxial substrate stretch

2019 ◽  
Author(s):  
Tamer Abdalrahman ◽  
Neil H. Davies ◽  
Thomas Franz
Keyword(s):  
Elastic Modulus ◽  
In Silico ◽  
Focal Adhesions ◽  
Element Model ◽  
Homogenization Method ◽  
Fibre Volume ◽  
Fibre Content ◽  
Peak Strain ◽  
Stress Fibre ◽  
A Cell

AbstractExisting in silico models for single cell mechanics feature limited representations of cytoskeletal structures that contribute substantially to the mechanics of a cell. We propose a micromechanical hierarchical approach to capture the mechanical contribution of actin stress fibres. For a cell-specific fibroblast geometry with membrane, cytoplasm and nucleus, the Mori-Tanaka homogenization method was employed to describe cytoplasmic inhomogeneities and constitutive contribution of actin stress fibres. The homogenization was implemented in a finite element model of the fibroblast attached to a substrate through focal adhesions. Strain in cell membrane, cytoplasm and nucleus due to uniaxial substrate stretch was assessed for different stress fibre volume fractions and different elastic modulus of the substrate. A considerable decrease of the peak strain with increasing stress fibre content was observed in cytoplasm and nucleus but not the membrane, whereas the peak strain in cytoplasm, nucleus and membrane increased for increasing elastic modulus of the substrate.

An Elastic-Plastic Finite Element Model of Rolling Contact, Part 2: Analysis of Repeated Contacts

1985 ◽  
Vol 52 (1) ◽  
pp. 75-82 ◽  
Author(s):  
V. Bhargava ◽  
G. T. Hahn ◽  
C. A. Rubin
Keyword(s):  
Finite Element ◽  
Shear Strain ◽  
Element Model ◽  
Rolling Contact ◽  
Elastic Plastic ◽  
Perfectly Plastic ◽  
Rolling Contacts ◽  
Elastic Perfectly Plastic ◽  
Multiple Translations ◽  
Contact Part

This paper presents finite element analyses of two-dimensional (plane strain), elastic-plastic, repeated, frictionless rolling contact. The analysis employs the elastic-perfectly plastic, cycle and strain-amplitude-independent material used in the Merwin and Johnson analysis but avoids several assumptions made by these workers. Repeated rolling contacts are simulated by multiple translations of a semielliptical Hertzian pressure distribution. Results at p0/k = 3.5, 4.35, and 5.0 are compared to the Merwin and Johnson prediction. Shakedown is observed at p0/k = 3.5, but the comparisons reveal significant differences in the amount and distribution of residual shear strain and forward flow at p0/k = 4.35 and p0/k = 5.0. The peak incremental, shear strain per cycle for steady state is five times the value calculated by Merwin and Johnson, and the plastic strain cycle is highly nonsymmetric.

Dynamic Modeling of Flat Belt Drives Using the Elastic-Perfectly-Plastic Friction Law

2009 ◽  
Author(s):  
Dooroo Kim ◽  
Michael Leamy ◽  
Aldo Ferri
Keyword(s):  
Equations Of Motion ◽  
Element Model ◽  
Friction Model ◽  
Local Perturbation ◽  
Belt Drive ◽  
Equilibrium Solutions ◽  
Friction Law ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic ◽  
Nonlinear Equations Of Motion

An analysis of a physically-motivated friction model called the Elastic/Perfectly-Plastic (EPP) friction model was performed on a steadily rotating flat belt drive. The EPP friction law is modeled as an elastic spring in series with an ideal Coulomb damper. The belt kinematics were developed and the nonlinear equations of motion and equilibrium solutions were derived using Hamilton’s Principle. Unlike the belt mechanics analyzed with Coulomb friction, the current study predicts the absence of adhesion zones. A stability analysis demonstrates that the non-linear equilibrium solution found is stable under local perturbation. A two-pulley belt drive with equal radii is analyzed and the dynamic response is studied. The results are compared to those computed using a dynamic finite element model. Excellent agreement between the two methods is documented.

Effects of Friction Coefficient and Receptor Number on Cell-Substrate Interactions During Migration

2010 ◽  
Author(s):  
Henry C. Wong ◽  
William C. Tang
Keyword(s):  
Cell Migration ◽  
Cancer Metastasis ◽  
Element Model ◽  
Biological Tissues ◽  
Substrate Interactions ◽  
Strain Behavior ◽  
Structural Support ◽  
Research Areas ◽  
Cell Substrate ◽  
A Cell

Biological tissues are composed of cells that adhere to the extracellular matrix (ECM) via cell-surface integrin receptors that bind to specific proteins, such as fibronectin, embedded in the matrix. In this manner, the ECM functions as a structural support for the attached cells, and mechanical forces are able to be transmitted from the cell to the ECM and vice versa [1]. Cell migration, a process that is highly dependent on these mechanical interactions, is important for many normal biological processes and diseases that occur in the human body, which include embryonic development, immune response, would healing, and cancer invasion [2]. Though many continuum models of cell migration have been proposed, there is still a need for a model that can be used to quantitatively understand the mechanical factors that can influence the movement of a cell on a substrate. This would be invaluable to the research areas of tissue engineering as well as cancer metastasis. We utilized a finite element model to elucidate the mechanism of cell-substrate interactions for a cell that consistently migrates in a single direction. Our model follows the approach taken by Gracheva and Othmer [2], but we extended their model to describe two-dimensional plane strain behavior.

The Estimation of Large Deflections of a Portal Frame Under Asymmetric Pulse Loading

1984 ◽  
Vol 51 (3) ◽  
pp. 494-500 ◽  
Author(s):  
J. L. Raphanel ◽  
P. S. Symonds
Keyword(s):  
Local Deformation ◽  
Elastic Response ◽  
Sensitive Material ◽  
Rigid Plastic ◽  
Finite Element Program ◽  
Perfectly Plastic ◽  
Portal Frame ◽  
Element Program ◽  
Loaded Column ◽  
Asymmetric Pulse

Modifications of a simple elastic-plastic technique [1-4] are shown which allow estimation of local deformation in the loaded column of a portal frame as well as the side-sway deflections of the frame. A wholly elastic response stage provides input to a simplified rigid-plastic solution, in which velocity patterns first of local and then of modal (side-sway) type occur, and which furnishes estimates of final plastic deflections. Maximum (elastic plus plastic) deflections are estimated by adding displacements corresponding to the elastic strain field defined by the stresses of the closing rigid-plastic mode. The method is described for perfectly plastic and for strain-rate sensitive material, and comparisons are shown here with values computed3 for both types of material by a finite element program. Emphasis in this paper is put on the inclusion of elastic and vicoplastic effects.

The Research on the Microstructure Evolution Law of Cross Wedge Rolling Asymmetric Shaft-Parts Based on Parity Wedge

2012 ◽  
Vol 201-202 ◽  
pp. 1121-1125 ◽  
Author(s):  
Wen Wei Gong ◽  
Xue Dao Shu ◽  
Wen Fei Peng ◽  
Bao Shou Sun
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Microstructure Evolution ◽  
Theoretical Foundation ◽  
Effective Means ◽  
Element Model ◽  
Nonlinear Finite Element Method ◽  
Cross Wedge Rolling ◽  
Rigid Plastic ◽  
Simulation Calculation

Microstructure evolution is an effective means to improve the mechanical properties of products, shaft parts formed by cross wedge rolling is not only the shape of the formed parts, but more importantly it improves the comprehensive mechanical properties of the products by deformation. Therefore, the paper sets up the coupled rigid-plastic finite element model with deformation-heat transfer-microstructure by using nonlinear finite element method, and this model is adopted to make simulation calculation for the forming techniques of asymmetric shaft parts of cross wedge rolling based on parity wedge, specifically analyzes the rule of dynamic recrystallization and grain size distribution in the asymmetric rolled parts. The results show that the grain in the wedging place of asymmetric shaft parts of cross wedge rolling based on parity wedge can be obviously refined, and the research results of this paper may provide theoretical foundation for further improving the quality and mechanical properties of asymmetric shafts parts of cross wedge rolling.

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