Evaluation of Plastic Deformation During Metal Forming by Using Lode Parameter

In the present research, the relationship between the strain increment and Lode parameter was obtained by using Lode parameter and Levy-Mises equation. The quantitative relation between different strain increments was presented and the relationship between plastic deformation types and Lode parameter was demonstrated. The relations between...

Equal-Channel angular pressing of high-carbon steel

This master thesis deals with the research to the effects of severe plastic deformation on the development of the microstructure and the mechanical properties of three low-alloyed high-carbon steels. The steels investigated include a hypo-eutectoid, an eutectoid and a hyper-eutectoid steel containing 0.61, 0.81 and 1.22 weight-percent carbon....

Amorphous-amorphous transition in glassy polymers subjected to cold rolling studied by means of positron annihilation lifetime spectroscopy

In this study, polycarbonate (PC) and polystyrene (PS) are subjected to plastic deformation by means of cold rolling and the resulting variation of the free volume and its subsequent time evolution after rolling is investigated by means of positron annihilation lifetime spectroscopy (PALS). The value of the long lifetime component that is...

Cyclic Plastic Deformation and Welding Simulation

One of the concerns of a fitness for purpose analysis is the quantification of the relevant material properties. It is known from experiments that the mechanical properties of a material can change due to a monotonic plastic deformation or a cyclic plastic deformation. For a fitness for purpose analysis to be accurate in these cases, it has to...

Viscoplasticity for instabilities due to strain softening and strain-rate softening

An interface element for modelling the onset and growth of mixed-mode cracking in aluminium and fibre metal laminates

Experimental monitoring of strain localization and failure behaviour of composite materials

Finite element procedure for modelling fibre metal laminates

Free edge delamination in carbon-epoxy laminates: A novel numerical/experimental approach

A stripyield model including effects of hold periods at constant load

Utilising the NLR Stripyield cycle-by-cycle fatigue crack growth model a basic description of the time dependent effects associated with periods of constant load level has been added to model Fatigue-Creep interactions. An outline of the basic Creep model is given along with flow diagrams of the sub programs added to the Stripyield model. Other...

Analysis of crack opening behaviour by application of a discretised strip yield model

The crack opening behaviour of a fatigue crack in a centrally cracked panel was studied using a discretised version of the Dugdale and Barenblatt model. The effect of crack growth was also included. Results obtain ed for constant amplitude loading were in agreement with data reported in the open literature. The effect of application of single...

Mechanica van het oprekken van gaten - Analysis of deformation and stresses near cold worked holes

In this report formulas are derived for a description of the deformation and stress fields near holes expanded by cold working. The results are compared with values obtained experimentally and calculated using the finite element method. The model of the material includes linear hardening and a yielding behaviour according to Tresca's criterion....

TEM "in situ" straining and bulk studies of the selection of glide systems in f.c.c. single crystals

Plastic deformation of f.c.c. single crystals was studied by means of straining experiments inside a transmission electron microscope on Cu foils and some related bulk straining experiments on Cu and Al single crystals. In the foils and bulk crystals with the same orientation of the normal to the large face the same non-primary glide...

A simple analytical model for computation of specimen compliance and effective crack extension force in a centrally cracked strip, including effects of yielding

In the present report a simple analytical model for the "behaviour of a centrally cracked strip is proposed. Formulae for computation of compliance, crack opening displacement and effective crack extension force are derived. The model is based on the classical solution for a crack infinite sheet under uniaxial tension. The effect of finite...

Theoretical and experimental analysis of elasto-plastic deformation in a uniaxially loaded strip of 2024 T3 rolled sheet material weakened by a central round hole

In this report strain ajid displacwnent measurements are described for a uniaxially loaded strip with a central rovind hole. The experiments are carried out in the elastio-plastic domain of the material. The strains and displacements are measured with use of respectively strain gauges and inductive displacement transducers. The test data...