Method of measuring large elastic-plastic strains of dynamically loaded plates and shells

1983 ◽  
Vol 15 (6) ◽  
pp. 770-778
Author(s):  
Z. G. Alpaidze ◽  
P. P. Lepikhin
Keyword(s):  
Plastic Strains ◽  
Elastic Plastic ◽  
Dynamically Loaded ◽  
Plates And Shells

Elastic-plastic strain distributions at fillet welds

1996 ◽  
Vol 31 (3) ◽  
pp. 215-230 ◽  
Author(s):  
K S Elliott ◽  
H Fessler
Keyword(s):  
Strain Range ◽  
Post Weld Heat Treatment ◽  
Steel Plates ◽  
Plastic Strains ◽  
Weld Toes ◽  
Thick Plates ◽  
Full Size ◽  
Elastic Plastic ◽  
Tensile Forces ◽  
Fringe Patterns

Steel plates 25 mm thick were fillet-welded to 50 mm thick plates according to good offshore welding practice. The thinner plates were inclined at 90° or 60° to the thicker ones to represent, at full size, the crown or saddle positions of a structural tubular T joint. Slices 4 mm or 10 mm thick were cut from these weldments and the elastic, elastic-plastic and residual plastic strains in the surfaces of these sections were measured using photoelastic coatings and moiré interferometry. The slices were loaded by tensile forces on the 25 mm wide parts, reacted at pin joints near the ends of the 50 mm wide part. The positions and directions of loading were arranged to load the welds in the same way as in a tubular T joint, loaded in tension. Yielding initiated at the weld toes and could be clearly identified in the moiré fringe patterns. It progressed into the plates, being inhibited by the heat-affected zone. Maximum plastic strains also occurred at the weld toes. Measurements of residual plastic strains showed that the actual strain range, which ‘drives’ fatigue failure, differs from predictions based on elastic analyses. Post-weld heat treatment is beneficial, but extending the weld along the plate reduces the strain concentrations much more.

The Inelastic Line-Spring: Estimates of Elastic-Plastic Fracture Mechanics Parameters for Surface-Cracked Plates and Shells

1981 ◽  
Vol 103 (3) ◽  
pp. 246-254 ◽  
Author(s):  
D. M. Parks
Keyword(s):  
Fracture Mechanics ◽  
Crack Growth ◽  
Computing Time ◽  
Crack Tip ◽  
J Integral ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Elastic Plastic ◽  
Plates And Shells ◽  
Crack Tip Opening

Recent studies of the mechanics of elastic-plastic and fully plastic crack growth suggest that such parameters as the J-integral and the crack tip opening displacement can, under certain conditions, be used to correlate the initiation and early increments of the ductile tearing mode of crack growth. To date, elastic-plastic fracture mechanics has been applied mainly to test specimen geometries, but there is a clear need for developing practical analysis capabilities in structures. In principle, three-dimensional elastic-plastic finite element analysis could be performed, but, in fact, such analyses would be prohibitively expensive for routine application. In the present work, the line-spring model of Rice and Levy [1-3] is extended to estimate the J-integral and crack tip opening displacement for some surface crack geometries in plates and shells. Good agreement with related solutions is obtained while using orders of magnitude less computing time.

Final shape of a dynamically loaded elastic- plastic redundant structure

AIAA Journal ◽  
1964 ◽  
Vol 2 (5) ◽  
pp. 958-958
Author(s):  
H. C. SCHJELDERUP ◽  
ROBERT E. BALL
Keyword(s):  
Final Shape ◽  
Elastic Plastic ◽  
Dynamically Loaded ◽  
Redundant Structure

Development of a Three-Dimensional Semi-Analytical Elastic-Plastic Contact Code

2002 ◽  
Vol 124 (4) ◽  
pp. 653-667 ◽  
Author(s):  
C. Jacq ◽  
D. Ne´lias ◽  
G. Lormand ◽  
D. Girodin
Keyword(s):  
Three Dimensional ◽  
Indentation Test ◽  
Closed Form Expression ◽  
Reciprocal Theorem ◽  
Plastic Strains ◽  
Surface Geometry ◽  
Fe Method ◽  
Elastic Plastic ◽  
Fine Mesh ◽  
The Reciprocal Theorem

A three-dimensional elastic-plastic contact code based on semi-analytical method is presented and validated. The contact is solved within a Hertz framework. The reciprocal theorem with initial strains is then introduced, to express the surface geometry as a function of contact pressure and plastic strains. The irreversible nature of plasticity leads to an incremental formulation of the elastic-plastic contact problem, and an algorithm to solve this problem is set up. Closed form expression, which give residual stresses and surface displacements from plastic strains, are obtained by integration of the reciprocal theorem. The resolution of the elastic-plastic contact using the finite element (FE) method is discussed, and the semi-analytical code presented in this paper is validated by comparing results with experimental data from the nano-indentation test. Finally, the resolution of the rolling elastic-plastic contact is presented for smooth and dented surfaces and for a vertical or rolling loading. The main advantage of this code over classical FE codes is that the calculation time makes the transient analysis of three-dimensional contact problems affordable, including when a fine mesh is required.

Numerical Simulation and Analysis for 3D Elastic-Plastic Rough Contacts

Tribology ◽  
2006 ◽  
Author(s):  
Fan Wang ◽  
Leon M. Keer ◽  
Q. Jane Wang
Keyword(s):  
Real Contact Area ◽  
Plastic Strains ◽  
Normal Contact ◽  
Elastic Plastic ◽  
Hardening Behavior ◽  
Real Contact ◽  
Residual Displacements ◽  
Surface Deflection ◽  
Plastic Hardening ◽  
Contact Field

A 3D elastic-plastic rough contact (EPC) solution and code is developed using a modified semi-analytical method. The total surface deflection is induced by the contact pressure and plastic strain. A purely elastic contact field and a residual field arising from the plastic deformation are simulated iteratively to gain the final approximate solution for the elastic-plastic rough contact. Frictionless normal contact between a rigid ball and an elastic-plastic half space with polished, turned, and honed rough surfaces was numerically simulated using the developed EPC code. The distributions of surface pressures, real contact area, total stresses, residual stresses, residual displacements, and plastic strains are obtained through simulation. The effects of surface roughness, wavelength, and plastic hardening behavior upon the calculated results are analyzed.

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