Abstract In this work, a support vector machine (SVM) model was developed to predict the hot deformation flow curves of AZ91 magnesium alloy. The experimental stress-strain curves, obtained from hot compression testing at different deformation conditions, were sampled. Consequently, a data base with the input variables of the deformation temperature, strain rate and strain and the output variab...

This paper presents a simple method based on strain energy density criterion to study the crack initiation angle by finite element method under biaxial loading condition. The crack surface relative displacement method is used to eliminate the calculation of the stress intensity factors which are normally required. The analysis is performed using higher order four node quadrilateral element. The...

The stress-strain behavior of toilet paper is studied. We find that the damaged parts of stress-strain curves possess a self-affine scaling invariance. Moreover, we find that the stress-strain behavior and the rupture line roughness are characterized by the same scaling (Hurst) exponent H, which is not universal: rather it changes from sample to sample. The variations on H are mainly due to flu...

Constitutive equations of cyclic strain and stress softening for materials with low internal stress levels are derived from the rate theory. The study shows that over the high stress and low temperature range where the description of plastic flow in cyclic softening can be approximated with activation over a single energy barrier, cyclic strain softening is well related to stress relaxation pro...

instruction: measurement of brachial artery diameter variation by ultrasound methods has commonly been used to test the endothelial function. it is known that the artery diameter is increased by flow stimulation. therefore in the present study, the effect of external obstruction, as flow stimulation, on the radial strain of the brachial artery was assessed. also the biomechanical behavior of th...

to investigate the hot deformation behavior of 17-7 ph stainless steel, hot compression tests were carried out at the temperatures of 950, 1050 and 1150 oc and strain rates of 0.001 s-1 to 0.1 s-1. accordingly, the hot working behavior was studied by the analyses of flow stress curves, work hardening rate versus stress curves, exponent- type constitutive equations and deformed microstructures. ...

AIMS Two-dimensional (2D)-strain derived from speckle-tracking is an alternative to tissue velocity imaging (TVI)-based strain. We compared their feasibility and accuracy in 150 patients undergoing dobutamine stress echocardiography (DSE) and coronary angiography. METHODS AND RESULTS 2D- and TVI-strain were obtained in three apical views at rest and peak stress. Peak systolic strain rate (SR)...

experimental study of the cyclic behavior of unsaturated materials is more complex than that of the saturated materials due to the required equipment, experience and time. furthering investigations in the field of unsaturated materials is necessary to better understand its complexity and sensitivity of unsaturated cyclic parameters to different determinants such as suction path, stress path, lo...

A simple constitutive model of shape memory alloys for analyses of tension–compression quasiplastic behavior is derived. Here, three martensitic variants are considered; namely, thermal-induced, tensile stress-induced, and compressive stress-induced martensitic variants. Reorientation from one variant to another variant is assumed to take place according to a reorientation energy criterion base...