Influence of lamellar structure on the stress–strain behavior of β nucleated polypropylene under tensile loading at elevated temperatures

RSC Advances ◽  
2015 ◽  
Vol 5 (54) ◽  
pp. 43496-43507 ◽  
Author(s):  
Tong Wu ◽  
Ming Xiang ◽  
Ya Cao ◽  
Jian Kang ◽  
Feng Yang
Keyword(s):  
Deformation Mechanism ◽  
Lamellar Structure ◽  
Elevated Temperatures ◽  
Tensile Loading ◽  
Schematic Diagram ◽  
Stress Strain ◽  
Strain Behavior

Schematic diagram of the deformation mechanism of β-iPP with different lamellae distributions when stretched at elevated temperatures.

Effect of Temperature on Cyclic Behavior of AZ31 Mg Alloy Sheet

2014 ◽  
Vol 939 ◽  
pp. 47-52
Author(s):  
Takashi Katahira ◽  
Syohei Hosokawa ◽  
Tetsuo Naka ◽  
Masahide Kohzu ◽  
Hiroki Adachi ◽  
...  
Keyword(s):  
Strain Rate ◽  
Deformation Mechanism ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Cyclic Stress ◽  
Tension Test ◽  
Cyclic Plasticity ◽  
Strain Rates ◽  
Stress Strain ◽  
Az31 Sheet

Magnesium alloy sheets have a potential to be widely used in many fields of industry due to their excellent lightweight property. Although magnesium alloys have low ductility at the room temperature due to their hexagonal close-packed structure, their formability can be improved at elevated temperatures. Therefore, warm press-forming of magnesium alloy sheets is an attractive technology. The objective of the present work is to investigate the cyclic plasticity behavior of an AZ31 sheet at elevated temperatures by performing cyclic tension-compression experiments. The cyclic deformation mechanism is examined by measuring the crystallographic orientation distributions by means of X-ray diffraction method at each stage of the cyclic deformation. The present findings are summarized as follows: (1) Stress-strain responses of an AZ31 sheet were investigated at various temperatures (R.T, 100, 150 and 200°C) at strain rates of 0.001, 0.01 and 0.05 s-1. The flow stresses were insensitive to the strain rate at the room temperature, however the strain rate dependency of the flow stress becomes dominant at elevated temperatures of over 100 °C.(2) Cyclic plasticity behavior of the sheet at various elevated temperatures (R.T, 100, 150 and 200 °C) at strain rates of 0.001, 0.01 and 0.05 s-1 were investigated by performing warm in-plane cyclic compression-tension test. Similarly to the uniaxial tension test, apparent temperature and strain rate dependencies of the flow stress were observed at temperatures of over 100 °C. (3) At the room temperature an unusual cyclic stress-strain curve, which is very different from that of bcc and fcc metals, was observed. From the texture measurement it was found that such a specific stress-strain characteristic is due to its twinning and detwinning deformation mechanism.(4) In contrast, at an elevated temperature of 200 °C, the usual cyclic stress-strain response, which is similar to one appearing in most of metallic materials, was observed. This is because the major deformation mechanism at an elevated temperature is the slip, rather than twinning/detwinning, since the CRSS decreases drastically with increasing temperature.

Effect Of Elevated Temperatures On Complete Concrete Deformation Diagrams

2019 ◽  
pp. 9-14
Keyword(s):  
Experimental Data ◽  
Elastic Modulus ◽  
Elevated Temperatures ◽  
Peak Load ◽  
Relative Deformation ◽  
Deformation Characteristics ◽  
Compression Tests ◽  
Strain Behavior ◽  
Different Temperatures ◽  
Deformation Diagrams

The analysis of the previous results of the study on concrete stress-strain behavior at elevated temperatures has been carried out. Based on the analysis, the main reasons for strength retrogression and elastic modulus reduction of concrete have been identified. Despite a significant amount of research in this area, there is a large spread in experimental data received, both as a result of compression and tension. In addition, the deformation characteristics of concrete are insufficiently studied: the coefficient of transverse deformation, the limiting relative compression deformation corresponding to the peak load and the almost complete absence of studies of complete deformation diagrams at elevated temperatures. The two testing chambers provided creating the necessary temperature conditions for conducting studies under bending compression and tension have been developed. On the basis of the obtained experimental data of physical and mechanical characteristics of concrete at different temperatures under conditions of axial compression and tensile bending, conclusions about the nature of changes in strength and deformation characteristics have been drawn. Compression tests conducted following the method of concrete deformation complete curves provided obtaining diagrams not only at normal temperature, but also at elevated temperature. Based on the experimental results, dependences of changes in prism strength and elastic modulus as well as an equation for determining the relative deformation and stresses at elevated temperatures at all stages of concrete deterioration have been suggested.

Stress Strain Behavior of Steel Fibre Based Concrete in Compression

2012 ◽  
Vol 1 (3) ◽  
pp. 32-38
Author(s):  
Tantary M.A ◽  
◽  
Upadhyay A ◽  
Prasad J ◽  
◽  
...  
Keyword(s):  
Steel Fibre ◽  
Stress Strain ◽  
Strain Behavior
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