The Journal of Strain Analysis for Engineering Design

Creep crack growth results are presented for five lead alloy beams, of depth 40 mm and width 80 mm, subjected to pure bending. The beams each contained semi-circular, crack-like, surface defects, of radius 5 mm, centrally positioned, in mode I opening. The deformation and crack growth from this defect are presented along with the uniaxial properties of the material. The creep crack growth correlates with previous results for plane specimens on the basis of the C∗ parameter. The ‘cracks’ where found to bifurcate under creep conditions and they grew in a direction suggesting equivalent stress-controlled damage of the material.

A numerical method to analyse unsteady thermal stresses in three-dimensional problems is proposed. It is shown that three-dimensional unsteady thermal stress problems can be easily solved without the volume integral by means of the thermoelastic displacement potential and the boundary element method. It is also shown that the time integral can be easily carried out analytically. In order to investigate the accuracy of this method, unsteady thermal stress distributions for a sphere and a circular cylinder are obtained. As a numerical example for which it is difficult to obtain the analytical solution, thermal displacements and surface stress distributions for a torus are obtained.

Two forms of rate-sensitive constitutive equations, additive and multiplicative, are examined in the analysis of sheet metal forming using the finite element method. Results are obtained for hemispherical punch stretching of an AK steel sheet material with various punch speeds. The computed results in thickness strain distributions and load-displacement curves are almost identical for the two constitutive laws at a low punch speed. However, the additive law provides better agreement in the thickness strain distributions with the experimental trends for high-speed forming.

A general method is described of determining the stress intensity factors for two-dimensional cracks composed of straight segments but with one or more angular discontinuities. The bulk stress field used is for illustrative purposes only, and the only requirement is that the crack remains open throughout its length.

Four kinds of 12-node solid finite elements with two parallel faces and one traction-free cylindrical surface have been developed based on the assumed stress hybrid method. Cylindrical coordinates are used so that the assumed stresses satisfy the equilibrium equations as well as the traction-free condition over the cylindrical boundary. In the limiting case of plane stress the assumed stresses also satisfy the compatibility conditions. Examples have indicated that these present special solid finite elements are far superior in predicting the distributions of the circumferential stresses and the stress concentration factors for solids with circular holes.

The stress analysis is carried out for the orthotropic plate subjected to arbitrarily distributed loads along the edges. The functional form of one stress acting in a plate is assumed and the fundamental equations governing the plate are introduced using the principle of complementary energy. A lap joint is analysed using the present method. From the results of the theoretical analysis, it becomes evident that the effect of the mechanical properties of the orthotropic plate on tearing stress is remarkably large.

During the sterilization process of a typical food can, the geometric non-linear and elastic-plastic state is confronted. A derived procedure of updated lagrangian incremental formulation is proposed to simulate the deformation behaviour of the food can. The process is illustrated with a real example. Some interesting results can be noted wherein.