Finite Element Analysis of Die-Strength Testing Configurations for Thin Wafers

2004 ◽  
Vol 127 (2) ◽  
pp. 189-192 ◽  
Author(s):  
X. K. Sun ◽  
X. J. Xin ◽  
Z. J. Pei
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Gradient ◽  
Strength Testing ◽  
Uniform Stress ◽  
Element Analysis ◽  
Ring Configuration ◽  
Die Surface ◽  
Uniform Stress Field ◽  
Point Bend

This paper presents an assessment of four die-strength testing configurations using finite element analysis. The simulation indicates that ring-on-ring configuration is the best because it generates a uniform stress field on a large die surface area. The four-point-bend configuration ranks second and the three-point-bend configuration is third. The pin-on-ring configuration is the worst because the stress gradient is severe in the central region. To minimize uncertainty in the loading positions, it is advised that loading rings or bars with small radii be used.

Bending Capacity Analyses of Corroded Pipeline

2011 ◽  
Vol 134 (2) ◽  
Author(s):  
Weiwei Yu ◽  
Pedro M. Vargas ◽  
Dale G. Karr
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Carrying Capacity ◽  
Nonlinear Finite Element ◽  
Secondary Effects ◽  
Element Analysis ◽  
Moment Capacity ◽  
Bend Testing ◽  
Bending Capacity ◽  
Point Bend

Appendix G of the ASME B31 pipeline and piping codes addresses the pressure containment capacity of pipelines and vessels with locally corroded sections. However, the ability of corroded sections to carry moment, for example, in thermal loops, is not addressed in fitness-for-service codes today. This paper presents nonlinear Finite Element Analysis (FEA) and full-scale 4-point-bend testing of pipes with locally-thinned-areas (LTAs) to simulate corrosion. The LTAs are loaded in compression, and the buckle moment is used as the carrying capacity of the corroded section. The nonlinear FEA is found to match the experimental results, validating this methodology for computing moment capacity in corroded sections. Significant secondary effects were found to affect the testing results. This paper identifies and quantifies these effects. Also, somewhat contrary to intuition, internal pressure is demonstrated to adversely affect the bending capacity for the intermediate-low D/t ratio (17.25) pipe tested.

Elastic Stress Concentration Factors (Kt) by Stress Gradient Method Using FEA

1996 ◽  
Author(s):  
Ajay Garg ◽  
Ravi Tetambe
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Maximum Stress ◽  
Elastic Stress ◽  
Stress Gradient ◽  
Nominal Stress ◽  
Element Analysis

Abstract The elastic stress concentration factor, Kt, is critical in determining the life of machines, especially in the case of notched components experiencing high cycle fatigue. This Kt is defined as the ratio of the maximum stress (σmax) at the notch to the nominal stress (σnom) in the region away from the notch effect. For simple geometries such as, plate with a hole, calculation of Kt from either closed form solution or from making simple but valid assumptions is possible [1,2]. However, for complex machine components such data is usually not available in the literature. Using Kt values from the simple geometries may lead to either over or under estimation of the real Kt for such complex geometries. Such error can then further lead to a substandard product or a product which is overdesigned and expensive. Present paper outlines a methodology for computing reasonably accurate elastic stress concentration factor, Kt, using finite element analysis (FEA) tool. The maximum stress (σmax) is readily available from the finite element analysis. The nominal stress (σnom) near the stress concentration is however can not be directly extracted from the FEA results. A novel approach of estimating reasonably accurate σnom is presented in this paper. This approach is based on selecting the correct path at the stress concentration region, post processing the stress and the stress gradient results along that path and identifying the cut of point where stress concentration effect begins to take place. This methodology is first validated using two examples with known Kt and later applied to a real world problem.

Model Building of Finite Element Analysis Based on ANSYS of Column Jib Crane

2012 ◽  
Vol 462 ◽  
pp. 427-433 ◽  
Author(s):  
Xiao Ma ◽  
Xue Li Cheng
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Model Building ◽  
Stress Gradient ◽  
Analysis Model ◽  
Element Analysis ◽  
Actual Structure ◽  
Improve Design ◽  
Displacement Boundary ◽  
Calculation Results

To improve design accuracy and shorten its cycle, finite element method is adopted in the process of crane designing. The integrated finite element analysis model was established for the whole column jib crane using finite element analysis software ANSYS. A feasible computational model which reflects the actual structure was built and displacement boundary condition was determined reasonably. By using the symmetries of structure and load, neglecting the specific structure of bearing but reserving motion relationship between slewing jib spindle and column bearing chamber, the model is simplified logically. The slewing jib, which has great stress gradient, was separated into two parts while its interface was maintained for different density when meshing. The model calculation results are in very good agreement with actual conditions which provide a theory basis for optimal design of integrated structure of column jib crane and modeling for products with similar structure.

Finite element analysis of peak stress and stress gradient at an elliptical through-hole

2017 ◽  
Vol 52 (5) ◽  
pp. 277-287
Author(s):  
Kristine Klungerbo ◽  
Gunnar Härkegård
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Plane Strain ◽  
Stress Gradient ◽  
Three Dimensional ◽  
Peak Stress ◽  
Two Dimensional ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Through Hole

The peak stress and stress gradient (parameters required for fatigue strength assessment) at an elliptical through-hole in a wide plate under uniaxial tension have been studied by means of three-dimensional finite element analysis with high mesh density. Dimensionless variables have been used throughout the investigation. The accuracy of two-dimensional finite element analysis has been assessed by extrapolating peak stress at an elliptical hole to infinite plate width and mesh density and comparing the extrapolated value with the closed-form Kolosov–Inglis solution (deviation < 0.2%). First- and second-order elements with full and reduced integration have been employed. Methods for determining stress gradients, using a varying number of nodal stresses, have been investigated. The accuracy of three-dimensional finite element analysis has been assessed by comparing the plane-strain peak stress for an elliptical through-hole with the corresponding plane-strain value from two-dimensional analysis (deviation < 0.1%). Peak stresses at the apex of the elliptical through-hole have also been determined for this three-dimensional mesh assuming a free plate surface. In particular, beside the maximum peak stress and its location, peak stresses have been determined at the surface and at the mid-plane of the plate for thicknesses ranging from 0.2 to 10 times the axis of the elliptical hole. The stress gradients at these locations have been determined, too. The minimum stress gradient is observed at the location of maximum stress. For sufficiently thin and thick plates, the mid-plane stresses approach two-dimensional plane-stress and generalised plane-strain solutions, respectively.

scholarly journals Proximal Cadaveric Femur Preparation for Fracture Strength Testing and Quantitative CT-based Finite Element Analysis

10.3791/54925 ◽  
2017 ◽  
Author(s):  
Dan Dragomir-Daescu ◽  
Asghar Rezaei ◽  
Susheil Uthamaraj ◽  
Timothy Rossman ◽  
James T. Bronk ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fracture Strength ◽  
Strength Testing ◽  
Quantitative Ct ◽  
Element Analysis
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