Local stress concentration and the prediction of tensile failure in unidirectional composites

1998 ◽  
Vol 57 (12) ◽  
pp. 1661-1672 ◽  
Author(s):  
H. Mahiou ◽  
A. Béakou
2016 ◽  
Vol 368 ◽  
pp. 121-125
Author(s):  
Pavel Kejzlar ◽  
Tomáš Pilvousek ◽  
Michal Tregler

The present work deals with determination of the cause of crack occurring in a part of car body manufactured from deep-drawing sheet. UHR-SEM, EDS, EBSD and measurement of microhardness were used for evaluation of the structure, local deformation and crack formation mechanism. A material analysis discovered foreign particles in the material. These particles were identified as MgAl2O4 with BCC lattice. The occurrence of these hard particles led to local stress concentration, decrease in mechanical strength and sheet breach due to tensile stress during deformation.


2014 ◽  
Vol 599-601 ◽  
pp. 385-390 ◽  
Author(s):  
Xue Xi Chen ◽  
Rui Qing Bi ◽  
Wen Guang Jin ◽  
Yong Xu

According to the conventional fracturing could easily lead to the local stress concentration of coal, the effect of pressure relief and permeability improvement is not ideal. The mechanism of directional hydraulic fracturing is analyzed and the parameters such as the layout of directional hole, the fracturing hole sealing, the minimum cracking pressure are discussed, then the field application tests are carried out. The results show that the directional hydraulic fracturing effect is better than that of ordinary fracturing hole and the maximum concentration and the average drainage scalar is respectively 3.75 times and 4 times of the ordinary hole pumping gas fracturing effects. The effect of permeability improvement is remarkable.


Author(s):  
Hiroaki Eto ◽  
Koji Iizuka ◽  
Ryo Nishigochi ◽  
Tomoki Ikoma ◽  
Yasuhiro Aida ◽  
...  

Abstract Indonesia is a main country supplying coal in the Asia-Pacific region, it is important to ensure a stable coal supply to Japan. Because the topography of the seabed near East Kalimantan Island, Indonesia’s main coal production area, is shallow, it is difficult for bulk carriers to reach the coast. Therefore, Large-Scale Floating Coal Transshipment Station (LFTS) was proposed, which will be used as a relay base between coal-barging barges from land and bulk carriers offshore. Installing an LFTS offshore from East Kalimantan is expected to improve coal transport productivity. LFTS can store coal equivalent to five times the capacity of one bulk carrier (total 500,000T), and can accommodate 2 bulk carriers at the same time during offloading. The scale of LFTS is 590m × 160m. The LFTS has a flat spread and the elastic behavior becomes the dominant Structure. The upper part of the LFTS is different rigidity partly because the partition wall to be loaded by dividing the coal into each quality is provided. Loaded coal not only changes the draft of the LFTS but also greatly deforms the LFTS and is expected to cause local stress concentration on the structural members. Therefore, this paper investigates wave response characteristics and stress characteristics with the coal loading of the LFTS, and then evaluation of structural strength by limit state design method. In this study, linear potential theory and the finite element method (FEM) were used to analyze the static hydroelastic motion under various coal loading condition and wave response of LFTS. And, to grasp the local stress concentration occurring inside the LFTS by using the response results, a detailed model modeling a complicated internal structure was prepared. Zooming analysis which is a method of giving the deformation result by the whole model of LFTS as forced displacement to the local detailed model was carried out. As a result, depending on the coal loading condition and wave conditions, it became clear that LFTS will be in a tough situation.


1980 ◽  
Vol 102 (1) ◽  
pp. 121-123 ◽  
Author(s):  
M. A. Mohamed ◽  
J. Schroeder

A method based on local stress concentration is employed to estimate stress intensity factors for corner cracks at the crotch corner of pressurized tees. The method yields results which are in good agreement with data obtained using other advanced numerical techniques.


2010 ◽  
Vol 163-167 ◽  
pp. 899-903
Author(s):  
Yun Xia Lun ◽  
Shao Shun Liu ◽  
Ming Kai Zhou ◽  
Xiao Fan Liu

A stress-chemistry method was used to investigate the expansion behavior of mortars made with steel slag sand (SSM). The results indicated that periclase and free CaO were the main mineral components resulted in expansion of SSM by means of volume increment and local stress concentration after hydration. So it can be concluded that stress concentration arised from enrichment and uneven distribution of expansile mineral components was the main reason resulted in the volume expansion of SSM. Model of expansion of SSM was built according to the characteristics of crack and types of versicolor particles.


Sign in / Sign up

Export Citation Format

Share Document