Dynamic Indentation of an Elastic-Plastic Multi-Layered Medium by a Rigid Cylinder

2004 ◽  
Vol 126 (1) ◽  
pp. 18-27 ◽  
Author(s):  
J. Yang ◽  
K. Komvopoulos
Keyword(s):  
Finite Element ◽  
Plane Strain ◽  
Layered Medium ◽  
Equivalent Stress ◽  
Contact Analysis ◽  
Radius Of Curvature ◽  
Dynamic Indentation ◽  
Rigid Cylinder ◽  
Elastic Plastic ◽  
Static Contact

A plane-strain analysis of dynamic indentation of an elastic-plastic multi-layered medium by a rigid cylinder was performed using the finite element method. Conversely to plane-strain static contact analysis, the solutions of a dynamic contact analysis within a subsurface domain adjacent to the contact region are independent of mesh size, provided the mesh dimensions are sufficiently large such that the propagating waves reflected from the artificial boundaries do not reach the domain of interest during the analysis. Simulation results for the normal force, contact pressure distribution, subsurface stresses, and evolution of plasticity in the multi-layered medium are presented in terms of the speed and radius of the rigid indenter. The likelihood of mechanical failure due to excessive plastic deformation and cracking is interpreted in terms of finite element results for the von Mises equivalent stress, first principal stress, and equivalent plastic strain obtained for different values of the indenter speed and radius of curvature.

Three-Dimensional Finite Element Analysis of Elastic-Plastic Layered Media Under Thermomechanical Surface Loading

2002 ◽  
Vol 125 (1) ◽  
pp. 52-59 ◽  
Author(s):  
N. Ye ◽  
K. Komvopoulos
Keyword(s):  
Finite Element ◽  
Layered Medium ◽  
Numerical Solutions ◽  
Equivalent Stress ◽  
Three Dimensional ◽  
Layered Media ◽  
Thin Layers ◽  
Surface Loading ◽  
Elastic Plastic ◽  
Thermomechanical Surface

The simultaneous effects of mechanical and thermal surface loadings on the deformation of layered media were analyzed with the finite element method. A three-dimensional model of an elastic sphere sliding over an elastic-plastic layered medium was developed and validated by comparing finite element results with analytical and numerical solutions for the stresses and temperature distribution at the surface of an elastic homogeneous half-space. The evolution of deformation in the layered medium due to thermomechanical surface loading is interpreted in light of the dependence of temperature, von Mises equivalent stress, first principal stress, and equivalent plastic strain on the layer thickness, Peclet number, and sliding distance. The propensity for plastic flow and microcracking in the layered medium is discussed in terms of the thickness and thermal properties of the layer, sliding speed, medium compliance, and normal load. It is shown that frictional shear traction and thermal loading promote stress intensification and plasticity, especially in the case of relatively thin layers exhibiting low thermal conductivity.

Effect of Residual Stress in Surface Layer on Contact Deformation of Elastic-Plastic Layered Media

2003 ◽  
Vol 125 (4) ◽  
pp. 692-699 ◽  
Author(s):  
N. Ye ◽  
K. Komvopoulos
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Surface Layer ◽  
Coefficient Of Friction ◽  
Layered Medium ◽  
Equivalent Stress ◽  
Equivalent Plastic Strain ◽  
Layered Media ◽  
Contact Loading ◽  
Elastic Plastic

The effect of residual stress in the surface layer on the deformation of elastic-plastic layered media due to indentation and sliding contact loading and unloading was analyzed with the finite element method. A three-dimensional finite element model of a rigid sphere interacting with a deformable layered medium was developed, and its accuracy was evaluated by contrasting finite element results with analytical solutions for the surface stresses of an elastic homogeneous half-space subjected to normal and friction surface traction. Deformation of the layered medium is interpreted in terms of the dependence of the von Mises equivalent stress, first principal stress, and equivalent plastic strain on the magnitudes of residual stress and coefficient of friction. The effect of residual stress on the propensity for yielding and cracking in the layered medium is discussed in the context of results for the maximum Mises and tensile stresses and the evolution of plasticity in the subsurface. It is shown that the optimum residual stress in the surface layer depends on the type of contact loading (indentation or sliding), coefficient of friction, and dominant deformation mode in the layer (i.e., plastic deformation or cracking).

Investigation on the uncertain factors of the elastic–plastic contact characteristics of the planetary roller screw mechanism

2018 ◽  
Vol 233 (5) ◽  
pp. 1795-1806
Author(s):  
Qin Yao ◽  
Yongshou Liu ◽  
Mengchuang Zhang ◽  
Geng Liu ◽  
Shangjun Ma
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Mathematic Model ◽  
Contact Analysis ◽  
Secondary Development ◽  
Elastic Plastic ◽  
Development Platform ◽  
Roller Screw ◽  
Screw Mechanism ◽  
Element Method

The scatter of uncertain factors of the planetary roller screw mechanism, which originated from the manufacturing process, has a significant influence on its serving performance. However, this influence remains insufficiently studied. Further, the elastic–plastic contact analysis of the planetary roller screw mechanism with considering the uncertainties needs large numbers of repetitive calculations by traditional finite element method, which is labor intensive and often impractical. In this paper, an uncertain model of the planetary roller screw mechanism, including parameterization and finite element calculation, is established to conduct the elastic–plastic contact analysis automatically. Besides, the finite element method results can be also obtained automatically with the self-compiled flow program and the secondary development platform using the design of experiment method. Then, a mathematic model is applied to value the influence of the uncertain factors on the contact characteristics. The Pareto graphs are plotted to clearly show this sequence of the percent effects of all the uncertain factors. The present work, for the first time, developed an automatic modeling method for analyzing efficiently the uncertain factors of planetary roller screw mechanism, which is worthy in industrial application.

The Finite Element Analysis on the Compression Splicing Position of Strain Clamp in Guy Tower

2014 ◽  
Vol 680 ◽  
pp. 249-253
Author(s):  
Zhang Qi Wang ◽  
Jun Li ◽  
Wen Gang Yang ◽  
Yong Feng Cheng
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Finite Element Model ◽  
Equivalent Stress ◽  
Element Model ◽  
Element Analysis ◽  
Elastic Plastic ◽  
The Finite Element Analysis

Strain clamp is an important connection device in guy tower. If the quality of the compression splicing position is unsatisfied, strain clamp tends to be damaged which may lead to the final collapse of a guy tower as well as huge economic lost. In this paper, stress distribution on the compressible tube and guy cable is analyzed by FEM, and a large equivalent stress of guy cable is applied to the compression splicing position. During this process, a finite element model of strain clamp is established for guy cables at compression splicing position, problems of elastic-plastic and contracting are studied and the whole compressing process of compressible position is simulated. The guy cable cracks easily at the position of compressible tube’s port, the inner part of the compressible tube has a larger equivalent stress than outside.

Three-Dimensional Elastic-Plastic Finite-Element Analysis of the Flattening of Wire Between Plain Rolls*

2000 ◽  
Vol 123 (3) ◽  
pp. 397-404 ◽  
Author(s):  
H. Utsunomiya ◽  
P. Hartley ◽  
I. Pillinger
Keyword(s):  
Finite Element ◽  
Elastic Recovery ◽  
Three Dimensional ◽  
Lateral Spread ◽  
Radius Of Curvature ◽  
Forming Process ◽  
Empirical Formulas ◽  
Element Analysis ◽  
Finite Element Program ◽  
Elastic Plastic

It is normal industrial practice to roll round edged flat wires from round circular wires using plain rolls. Although this is not a complex type of metal forming process, the internal deformation is highly three-dimensional. It is important to be able to determine the lateral spread, elongation and final profile precisely. In this paper, this process has been analyzed using an elastic-plastic finite element program. Firstly, algorithms for integrating the constitutive equations, i.e., return mapping algorithms, are evaluated to determine the most accurate technique. Then, the influences of friction and reduction in thickness on the deformation characteristics are investigated. The lateral spread and the radius of curvature of the free surface are quantitatively in reasonable agreement with those obtained from empirical formulas. The lateral spread increases with friction and with reduction. The variation of elongation in the roll bite is investigated in detail. It is found that the elongation is not uniformly distributed across the cross section. After passing the roll gap, the distribution is compensated by the elastic recovery of wire, otherwise it may cause edge waves.

Effects of Local Peak Stress Distribution on the Ratchet Limit

2002 ◽  
Author(s):  
Nobuyoshi Yanagida ◽  
Masaaki Tanaka ◽  
Norimichi Yamashita ◽  
Yukinori Yamamoto
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Plastic Strain ◽  
Equivalent Stress ◽  
Equivalent Plastic Strain ◽  
Peak Stress ◽  
Element Analysis ◽  
Stress Evaluation ◽  
Elastic Plastic ◽  
Plastic Analysis

Alternative stress evaluation criteria suitable for Finite Element Analysis (FEA) proposed by Okamoto et al. [1],[2] have been studied by the Committee on Three Dimensional Finite Element Stress Evaluation (C-TDF) in Japan. Thermal stress ratchet criteria in plastic FEA are now under consideration. Two criteria are proposed: (1) Evaluating variations in plastic strain increments, and (2) Evaluating the width of the area in which Mises equivalent stress exceeds 3Sm. To verify of these criteria, we selected notched cylindrical vessel models as prime elements. To evaluate the effect of the local peak stress distribution on these criteria, cylindrical vessels with a semicircular notch on the outer surface were selected for this analysis. We used two notch configurations for our analysis, and the stress concentration factor for the notches was set to 1.5 and 2.0. We conducted elastic-plastic analysis to evaluate the ratchet limit. Sustained pressure and alternating enforced longitudinal displacements which causes secondary stress were used as parameters for the elastic-plastic analysis. We found that when no ratchet was observed, the equivalent plastic strain increments decreased and the area in which Mises equivalent stress exceeds 3Sm are below the certain range.

Analysis of Gear Strength by Static and Dynamic Finite Element Methods

2016 ◽  
Vol 846 ◽  
pp. 318-324
Author(s):  
Chang Jiang Zhou ◽  
Si Yu Chen ◽  
Lin Ma
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Bearing Capacity ◽  
Finite Element Methods ◽  
Dynamic Contact ◽  
Contact Analysis ◽  
Hertz Contact ◽  
Gear Drive ◽  
Dynamic Finite Element ◽  
Static Contact

As key factor of numerical simulation for gear strength, namely determination of effective loads between meshing teeth profiles, their numerical calculation principles of static and dynamic finite element methods are analyzed according to the loads on gear teeth. The static analysis of gear strength can be classified to effective statics and static contact analysis, and the numerical simulation method for face distribution as the rule of Hertz contact is advanced. The differences between static and dynamic contact and their influences in results are researched. Compared with the empirical formulas, the analytical results about bearing capacity of gear drive under different effective loads show: (1) As the sequence of concentrated force, linear distribution force, face distribution force as the rule of Hertz contact, static contact analysis, the accuracy and reliability of calculating results under different effective loads are improved, especially the results from face distribution and static contact being very close. (2) Dynamic contact analysis can be used to simulated the effect well. The above studies could be referenced to calculation in bearing capacity of gear drive.

scholarly journals FE Analysis on Contact Properties between Root- Blade and Slot-Disc

2011 ◽  
Vol 2-3 ◽  
pp. 932-935 ◽  
Author(s):  
Bo Ping Wang ◽  
Jiao Wang ◽  
Xing Zhan Li ◽  
Qing Kai Han
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Contact Pressure ◽  
Equivalent Stress ◽  
Element Model ◽  
Contact Analysis ◽  
The Finite Element Method ◽  
Concentration Effects ◽  
Rotating Speed ◽  
Disk Structure

The contact problem between root-blade and slot-disk structure of compressor is of much importance, because there is serious stress concentration in the structure, which is one of the parts with multi faults in aero-engine. First, finite element model for dovetail attachment is established to analyze stress concentration effects. Then, the stress distribution and other parameters such as contact pressure is obtained through contact analysis. In this paper, the finite element method based on contact analysis is used. Calculating results show that equivalent stress, contact pressure of blade-disk structure increase steadily as the rotating speed increases.

Analysis of Deformation in Widening Project of Expressway by Finite Element Method

2013 ◽  
Vol 717 ◽  
pp. 290-294
Author(s):  
Teng Ai
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Plane Strain ◽  
Influence Factors ◽  
Foundation Settlement ◽  
Elastic Plastic ◽  
Element Method

This paper analyzes the deformation rule of the new and old roadbed when the new road splicing the old road directly by elastic-plastic plane strain finite element method (FEM).It also analyzes the influence factors of the new and old road foundation settlement by calculating, including the width and height of the embankment, the thickness and deformation module of the groundwork, and widen way.

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