The Interaction of Discontinuity Surfaces in Plastic Fields of Stress

1948 ◽  
Vol 15 (3) ◽  
pp. 261-264
Author(s):  
Alice Winzer ◽  
G. F. Carrier
Keyword(s):  
Stress Field ◽  
Fundamental Solution ◽  
Boundary Conditions ◽  
Constant Stress ◽  
Discontinuity Surfaces

Abstract A fundamental solution for problems associated with discontinuity surfaces in the field of stress has been developed by W. Prager, but the accuracy with which it approximates the stress field obtained in actual materials under the same boundary conditions has not been established. In this paper a study is made of the limited case in which the discontinuity surfaces may intersect when they separate fields of constant stress. The results may be applied to more general intersecting fields.

Linear Static, Real-Time Finite Element Computations Based on Element Masks

2011 ◽  
Author(s):  
Holger Graf ◽  
Andre´ Stork
Keyword(s):  
Finite Element ◽  
Stress Field ◽  
Boundary Conditions ◽  
Real Time ◽  
Stiffness Matrix ◽  
New Method ◽  
Stress Distributions ◽  
Post Processing ◽  
Time Performance ◽  
Computational Overhead

This paper presents a new method for the manipulation of a given CAE domain in view of VR based explorations that enables engineers to interactively inspect and analyze a linear static domain. The interactions can ideally be performed in real-time in order to provide an intuitive impression of the changes to the underlying volumetric domain. We take the approach of element masking, i.e. the blending out of computations resulting from computational overhead for inner nodes, based on the inversion of the stiffness matrix. This allows us to optimize the re-simulation loop and to achieve real-time performance for strain and stress distributions with immediate visualization feedback caused by interactively changing boundary conditions. The novelty of the presented approach is a direct coupling of view dependent simulations and its close linkage to post-processing tasks. This allows engineers to also inspect the changes of the stress field inside of the volume during, e.g. cross sectioning.

Influence of Porosity on Plane Strain Tensile Crack-Tip Stress Fields in Elastic-Plastic Materials: Part I

1992 ◽  
Vol 59 (3) ◽  
pp. 559-567 ◽  
Author(s):  
W. J. Drugan ◽  
Y. Miao
Keyword(s):  
Stress Field ◽  
Closed Form ◽  
Normal Stress ◽  
Plane Strain ◽  
Plane Stress ◽  
Entire Range ◽  
Crack Tip ◽  
Constant Stress ◽  
Tensile Crack ◽  
Stress Discontinuity

We perform an analytical first study of the influence of a uniform porosity distribution, for the entire range of porosity level, on the stress field near a plane strain tensile crack tip in ductile material. Such uniform porosity distributions (approximately) arise in incompletely sintered or previously deformed (e.g., during processing) ductile metals and alloys. The elastic-plastic Gurson-Tvergaard constitutive formulation is employed. This model has a sound micromechanical basis, and has been shown to agree well with detailed numerical finite element solutions of, and with experiments on, voided materials. To facilitate closed-form analytical results to the extent possible, we treat nonhardening material with constant, uniform porosity. We show that the assumption of singular plastic strain in the limit as the crack tip is approached renders the governing equations statically determinate with two permissible types of near-tip angular sector: one with constant Cartesian components of stress (“constant stress”); and one with radial stress characteristics (“generalized centered fan”). The former admits an exact asymptotic closed-form stress field representation, and although we prove the latter does not, we derive a highly accurate closed-form approximate representation. We show that complete near-tip solutions can be constructed from these two sector types for the entire range of porosity. These solutions are comprised of three asymptotic sector configurations: (i) “generalized Prandtlfield”for low porosities (0 ≤ f ≤ .02979), similar to the plane strain Prandtl field of fully dense materials, with a fully continuous stress field but sector extents that vary with porosity; (ii) “plane-stress-like field” for intermediate porosities (.02979 < f < .12029), resembling the plane stress solution for fully dense materials, with a ray of radial normal stress discontinuity but sector extents that vary with porosity; (iii) two constant stress sectors for the remaining high porosity range, with a ray of radial normal stress discontinuity and fixed sector extents. Among several interesting features, the solutions show that increasing porosity causes significant modification of the angular variation of stress components, particularly for a range of angles ahead of the crack tip, while also causing a drastic reduction in maximum hydrostatic stress level.

Influence of Boundary Conditions on Higher Order Terms of Near-Crack-Tip Stress Field in a WST Specimen

2011 ◽  
Vol 488-489 ◽  
pp. 399-402 ◽  
Author(s):  
Václav Veselý ◽  
Lucie Šestáková ◽  
Stanislav Seitl
Keyword(s):  
Stress Field ◽  
Boundary Conditions ◽  
Numerical Study ◽  
Higher Order ◽  
Wedge Splitting Test ◽  
Splitting Test ◽  
Higher Order Terms ◽  
Test Geometry ◽  
Finite Element Package ◽  
Stress And Deformation

A precise description of the stress and deformation fields in a cracked body is provided using multi-parameter fracture mechanics based on the approximation of the fields by means of the Williams’ power series. This paper presents a detailed analysis of the stress field in a wedge-splitting test geometry specimen aimed at the calculation of coefficients of the higher order terms (up to 14) of the Williams’ expansion. The numerical study is conducted with the use of a conventional finite element package; however, for processing of the results an over-deterministic method is employed. Special attention is paid to the influence of boundary conditions of the test geometry on the values of the coefficients of the higher order terms of the Williams’ series. The results are compared to data from the literature; a strong effect of the boundary conditions is observed.

Engineering Application of the Slope Failure Criterion

2014 ◽  
Vol 962-965 ◽  
pp. 1143-1146
Author(s):  
Wei Shui Fei ◽  
Cong Ling Zhang ◽  
Peng Xiang Shen
Keyword(s):  
Stress Field ◽  
Boundary Conditions ◽  
Failure Criterion ◽  
Slope Failure ◽  
Failure Process ◽  
Engineering Application ◽  
Material Control ◽  
Unstable Failure ◽  
Rock And Soil ◽  
Sliding Zone

Abstract: The nouniformity of rock and soil materials and differences of boundary conditions caused the differentiation of stress field, together with the elastic-plastic characteristics of sliding zone material control the progressive unstable failure process. In this paper, The analysis of engineering example shows that the mechanical criterion is reasonable to judge the state of progressive slope evolution.

Constant Stress Field Measurements Through Thermoelasticity

2013 ◽  
Vol 36 (7) ◽  
pp. 672-683 ◽  
Author(s):  
A. Garinei ◽  
M. Becchetti ◽  
E. Pucci ◽  
G. Rossi
Keyword(s):  
Stress Field ◽  
Field Measurements ◽  
Constant Stress

STRESS BEHAVIOR IN THE NEIGHBORHOOD OF SHARP CORNERS

Geophysics ◽  
1964 ◽  
Vol 29 (3) ◽  
pp. 360-369 ◽  
Author(s):  
Frank C. Karal ◽  
Samuel N. Karp
Keyword(s):  
Stress Field ◽  
Boundary Conditions ◽  
Practical Reasons ◽  
Elastic Media ◽  
Elastic Wedge ◽  
Arbitrary Angle ◽  
Free Boundary Conditions ◽  
Stress Behavior ◽  
Sharp Corners ◽  
Stress Free Boundary

Knowledge of the behavior of the stress field in the neighborhood of cracks and sharp corners is important for many theoretical and practical reasons. In an earlier paper the authors examined the behavior of the stress field near the edge of an elastic wedge of arbitrary angle with stress‐free boundary conditions prescribed on both surfaces (Karp and Karal, 1962). Other types of boundary conditions, such as those representing rigid and lubricated boundaries, were not considered. In the present paper these boundary conditions are now studied, and the behavior of the stress field in the neighborhood of the tip is determined. In addition, the stress behavior is examined when two different elastic media meet at a sharp edge.

Sign in / Sign up

Export Citation Format

Share Document