An Experimental Study of Dropped Ply Region in Composite

2006 ◽  
Vol 326-328 ◽  
pp. 1769-1772
Author(s):  
Chun Wang Zhao ◽  
Yong Ming Xing
Keyword(s):  
Experimental Study ◽  
Stress Concentration ◽  
Failure Mechanisms ◽  
Experimental Results ◽  
Epoxy Composites ◽  
Moire Interferometry ◽  
Concentration Region ◽  
Micro Cracks ◽  
Stress Concentration Region ◽  
Mechanical Study

A micro mechanical study of Carbon/Epoxy composites with internally dropped plies has been made using micro-moiré interferometry. The experimental results show that there is a stress concentration region before the dropped ply. Micro cracks were initiated and propagated in this region. Two failure mechanisms in the dropped ply region were observed.

Advancements in Micro-Structure with Multiple Stress Concentration Region for Bionic Vector Hydrophone

2015 ◽  
Vol 645-646 ◽  
pp. 555-560
Author(s):  
Guo Jun Zhang ◽  
Peng Zhao ◽  
Wen Dong Zhang
Keyword(s):  
Stress Concentration ◽  
Constant Force ◽  
Ansys Software ◽  
Micro Structure ◽  
Concentration Region ◽  
Multiple Stress ◽  
Upper Limit ◽  
Stress Concentration Region ◽  
Vector Hydrophone ◽  
Different Shapes

The method of Multiple Stress Concentration Regions (MSCRs) on the surface of MEMS Silicon micro-structure is introduced in order to enhance the sensibility of the hair vector hydrophone without reducing the working bandwidth. The MSCRs with the thickness and width smaller than the rest of the cantilever can produce localized stress concentration when constant force is applied on the structure. ANSYS software has been used as a tool to analyze the effect of different shapes and dimensions on the performance of the micro-structure. The optimum MSCR has been obtained. Results show that compared with the ordinary structure, the sensitivity of the micro-structure with MSCR can be increased by 1.5 times, and the upper limit of bandwidth can be improved from 337Hz to 500Hz. This paper provides a new method to resolve contradiction between the sensitivity and working bandwidth.

Application Research on Concrete Filled Steel Tube Supports Supporting Technology in Stress Concentration Roadway

2012 ◽  
Vol 594-597 ◽  
pp. 773-778 ◽  
Author(s):  
Guo Lei Liu ◽  
Jun Wang ◽  
Hai Bin Wang ◽  
Xiao Sheng He ◽  
Xue Bin Li
Keyword(s):  
Stress Concentration ◽  
Coal Pillar ◽  
Mining Area ◽  
Steel Tube ◽  
Surrounding Rock ◽  
Concentration Region ◽  
Concrete Filled Steel Tube ◽  
Rapid Construction ◽  
Stress Concentration Region ◽  
Mining Coal

Part of the east wing belt roadway in -450 level east, NO.1 mining area, Dashu village coal mine, Jizhong Energy Fengfeng Group was under the 172102 working face’s stop mining coal pillar. The phenomenon of the stress concentration was obvious, the pressure of the roadway was large and the surrounding rock damaged severely. Concrete filled steel tube supports were used in stress concentration region. The supports type was φ194×8mm, and distance between supports was 800mm. They were of rapid construction speed, better supporting effect. The numerical simulation results also showed that the concrete filled steel tube supports can reduce deformation of the roadway surrounding rock in stress concentration region effectively.

An Experimental Study on Creep Deformation of PBX with Laser Moiré Interferometry Method

2006 ◽  
Vol 306-308 ◽  
pp. 1037-1042 ◽  
Author(s):  
Hui Min Xie ◽  
Hang Shi ◽  
Peng Wan Chen ◽  
Feng Lei Huang ◽  
Dai Ning Fang
Keyword(s):  
Experimental Study ◽  
Creep Deformation ◽  
Damage Mechanics ◽  
Moiré Interferometry ◽  
Experimental Results ◽  
Creep Process ◽  
Moire Interferometry ◽  
High Polymer ◽  
Interferometry Method

In this paper, the creep deformation of PBX was measured using the moiré interferometry. The experimental results show a different creep process compared with pure high polymer and this phenomenon is preliminary analyzed from damage mechanics.

Microstructural Analysis of Low-Cycle Fatigue Damage Process of Sn-Ag-Cu Solder Joint

2013 ◽  
Author(s):  
Hiroyuki Kontani ◽  
Yoshiharu Kariya ◽  
Tomoya Fumikura
Keyword(s):  
Stress Concentration ◽  
Solder Joint ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue ◽  
High Angle ◽  
Concentration Region ◽  
Joint Area ◽  
Stress Concentration Region

In this study, the relationship between microstructural change and fracture in the process of low-cycle fatigue of Sn-Ag-Cu solder joint was investigated using the solder ball of 630μm and 100μm in diameter by analysis of crystallographic orientation by means of EBSD. The 630μm specimen has subgrain boundaries formed by dynamic recovery in the stress concentration region, and the subgrain boundaries become high-angle random grain boundaries by additional cycles. The fatigue crack stably propagates along the random grain boundary in the stress concentration region. In contrast, the 100μm specimen has subgrain boundaries and high-angle random grain boundaries formed across the entire joint area. Since the occurrence of grain boundary fracture across the entire joint area by the connection of high energy grain boundaries, the crack propagation life of the 100μm specimen shortens without the stable crack growth compared to the 630μm specimen.

Application on Enhanced Permeability Outburst Prevention Technology of Hydraulic in Rock Cross-Cut Coal Uncovering

2015 ◽  
Vol 1092-1093 ◽  
pp. 1366-1370 ◽  
Author(s):  
Jian Jun Cao
Keyword(s):  
Stress Concentration ◽  
Coal Seam ◽  
Active Role ◽  
Favourable Effect ◽  
Gas Release ◽  
Concentration Region ◽  
Stress Concentration Region ◽  
Hydraulic Equipment ◽  
Practical Engineering ◽  
New Type

According to the practical engineering in Daxing Coal Mine north limb centralized down transportation, the No 13 coal seam rock cross-cut area with high gas pressure and content was serious outburst hazardof. Based on the technical principle and protection outburst mechanism of hydraulic in depressurization and enhanced permeability, the hydraulic drills in rock cross-cut coal uncovering were desinged, and the hydraulic equipment was matched, the measures were constructed, the effect was tested. The results show that the new type integration technology of the integrative hydraulic drilling and reaming obvious increased the plasticity of coal, reduced the stress concentration region of coal seam, improved the permeability of coal, promoted gas release, enhanced the ability of preventing coal and gas breakout, which played an active role in comprehensive outburst controlling, obtain ed a favourable effect in rock cross-cut coal uncovering and has important popularized and applied values.

Finite Element Analysis of Stress for Nozzle Zone at Channel of Pressure Vessel

2012 ◽  
Vol 490-495 ◽  
pp. 2165-2168 ◽  
Author(s):  
Xiao Lv ◽  
Shi Jie Wang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentration ◽  
Pressure Vessel ◽  
Maximum Stress ◽  
Concentration Region ◽  
Element Analysis ◽  
Stress Concentration Region ◽  
Before And After ◽  
The Status

With the development of petrochemical industry, the status of pressure vessel has become increasingly important, and higher requirements are introduced for the security of nozzle zone at the pressure bearing region of pressure vessel. In order to study the stress status of nozzle zone at the channel of pressure vessel, solid modeling for channel and straight pipe was performed with ANSYS software. Through finite element analysis and calculation, the stress concentration region of channel was determined and the reason was analyzed. In addition, the nozzle zones of the model before and after loading were compared. The result reveals that symmetrical stress concentration region lies at the junction of channel and pipe. The maximum stress is located at the inside of nozzle zone of channel and less than the yield stress of material.

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