Radial Stress Release Phenomena in Plate Impact Experiments: Compression-Release

1972 ◽  
Vol 39 (2) ◽  
pp. 359-366 ◽  
Author(s):  
A. L. Stevens ◽  
O. E. Jones
Keyword(s):  
Radial Stress ◽  
Residual Effects ◽  
Stress Release ◽  
Plate Impact ◽  
Secondary Importance ◽  
Physical Experiments ◽  
Impact Experiment ◽  
Circular Target ◽  
The Impact ◽  
Impact Experiments

A common objective in designing a postmortem type of plate-impact experiment is to be able to attribute the observable residual effects (such as residual strain, hardness, or dislocation density) primarily to the conditions which existed while the material was in a state of uniaxial strain. In the past it has generally been assumed that effects due to radial stress release phenomena, which are always present in such an experiment, are of secondary importance. In order to test the validity of this assumption, a two-dimensional Lagrangian finite-difference computer program is used to model physical experiments representative of common practice. Target plate dimensions, the target and flyer plate material, and the impact velocity are systematically varied for circular target plates with, and without, guard rings. The results show that in many cases the effects of radial release phenomena are too large to ignore. Conclusions are presented which serve as guidelines for designing experiments to minimize radial release effects.

scholarly journals Analysis and Experimental Study of Acceleration Model for Short Interval and Multiple Impact Equipment

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Feiyin Li ◽  
Shaojie Ma
Keyword(s):  
Stress Wave ◽  
Short Interval ◽  
High Impact ◽  
Line Contact ◽  
Acceleration Model ◽  
Impact Experiment ◽  
Impact Acceleration ◽  
Multiple Impact ◽  
The Impact ◽  
Impact Experiments

Short interval and continuous high-impact experiments have very significant engineering application values, and impact acceleration is a key performance index of these dynamic experiments. This paper aims at the shortcomings of the existing multiple high-impact equipment, designs a new type of multiple high-impact equipment based on the collision contact mode by multiple impact components, and studies the composition of acceleration in impact experiment. The research results indicate that it is unreasonable to analyze the impact acceleration only based on rigid body dynamics theory and ignore the effect of the stress wave loading during an impact experiment. On this basis, a line contact model is adopted to modify the equivalent damping coefficient and obtain a nonlinear spring damping contact force model based on the line contact, and then a rigid body acceleration model of the impact experiment is established. A stress wave acceleration model is also established based on the one-dimensional stress wave transfer theory of the tested specimen. The established acceleration model is verified by different corresponding impact experiments. At the same time, the collision contact process of the impact experiment is also simulated which is combined with the finite element method. The simulation results were fundamentally consistent with the experiments and a fact that proves the correctness of analysis and modeling. The research results not only provide theoretical support for the design and analysis of the impact equipment and a new idea to realize multiple high-impact loading but also provide a methodology to be applied to the analysis and modeling of acceleration for similar high-impact experiments.

Experimental Research on Buckling of Nano-Thin Film under Impact Load

2011 ◽  
Vol 130-134 ◽  
pp. 1262-1265
Author(s):  
Peng Li ◽  
Linan Li ◽  
Jing Wei Tong ◽  
Shi Bin Wang ◽  
Min Zhang ◽  
...  
Keyword(s):  
Thin Film ◽  
Impact Load ◽  
Film Surface ◽  
Local Distribution ◽  
Pmma Substrate ◽  
Stress Release ◽  
Drop Hammer ◽  
Initiation And Propagation ◽  
The Impact ◽  
Impact Experiments

The experiments focused on thin film buckling under impact load had been completed. The axial impact experiments were done to different films on the PMMA substrate with the drop hammer device, the buckling images of the film surface were recorded after impact, and the problem of stress release was studied. It was found that buckle’s initiation and propagation were influenced by the materials of thin films and the impact times, and meanwhile buckle’s local distribution phenomenon was also found.

scholarly journals Emissivity change in pressure-shear plate impact experiment

2020 ◽  
Author(s):  
T. Jiao ◽  
P. Malhotra ◽  
R. J. Clifton
Keyword(s):  
Plate Impact ◽  
Shear Plate ◽  
Impact Experiment

scholarly journals Influence of Age on the Technical Wear of Tenement Houses

2020 ◽  
Vol 11 (1) ◽  
pp. 297
Author(s):  
Jarosław Konior ◽  
Marek Sawicki ◽  
Mariusz Szóstak
Keyword(s):  
Residential Buildings ◽  
Residential Building ◽  
Numerical Approach ◽  
Technical Condition ◽  
Visual Methods ◽  
Secondary Importance ◽  
Building Maintenance ◽  
Technical Maintenance ◽  
Traditional Construction ◽  
The Impact

The research presented in the article, which includes methods, models, and conclusions, contains synthetic and analytical model solutions concerning the problems of the technical maintenance and wear of residential buildings with a traditional construction. The cause and effect relationships between the occurrence of damage in the elements of tenement houses (treated as proof of their maintenance conditions), and the size of the technical wear of these elements were determined using a representative and purposefully selected sample of 102 residential buildings erected during the second half of the nineteenth and early twentieth centuries in Wroclaw’s “Downtown” district. Quantitative damage analysis, which was carried out using empirical (visual) methods of assessing the technical condition of a building, indicates the type and size of damage to the building’s elements that are characteristic for the relevant maintenance conditions. Research concerning the cause–effect relationships (“damage–technical wear”) in observed states allows for a numerical approach to the impact of building maintenance conditions on the degree of the technical wear of its components. The maintenance and exploitation conditions determine the degree of the technical wear of the elements of an old residential building. The exploitation condition of these buildings is manifested by damage to elements caused by water and moisture penetration, which is especially important for poorly maintained buildings. The article shows that the age of the elements of an old residential building with a traditional construction is of secondary importance in the process of the intensity of losing its serviceability value. It was calculated that no more than 30% of the damage of building components is explained by the passage of time, and it is therefore not age that determines the course of the technical wear of the elements of the analyzed tenement houses.

Computational Simulations of Dynamic Compaction of Dry Sand

2012 ◽  
Vol 598 ◽  
pp. 516-519
Author(s):  
Yu Qing Ding ◽  
Wen Hui Tang ◽  
Xian Wen Ran ◽  
Xin Xu
Keyword(s):  
Computational Analysis ◽  
Dynamic Compaction ◽  
Back Surface ◽  
Computational Results ◽  
Two Dimensional ◽  
Computational Simulations ◽  
Plate Impact ◽  
Arrival Times ◽  
Dry Sand ◽  
Impact Experiments

The computational analysis of plate impact experiments on dry sand utilizing the Mie- Grüneisen (MG) equation of state and the P-α compaction model were investigated in this study. A number of two dimensional axial symmetric computations were performed by using the hydrocode AUTODYN. The computational results were compared with the particle velocity on the back surface of the rear plate measured by the VISAR system and the first shock-wave arrival times detected by piezoelectric pins in the samples respectively. It was found that the P-α compaction model was more accurately reproduce the experimental data than the MG EOS.

The Performance Analysis of Calcium Silicate Composited Wall's Impact Resistance

2013 ◽  
Vol 671-674 ◽  
pp. 596-601
Author(s):  
Ming Ming Chen ◽  
Zhong Tao ◽  
Hen Min Zhang ◽  
Wen Zheng Yu
Keyword(s):  
Performance Analysis ◽  
Calcium Silicate ◽  
Impact Resistance ◽  
Engineering Application ◽  
National Standard ◽  
Minimum Standard ◽  
Impact Experiment ◽  
Interior Walls ◽  
The Impact

This paper introduces the impact experiment and an engineering application of the new composited wall which composed of calcium silicate composited board. Clearly defines the impact resistance of the wall in different connection as interior walls and exterior walls through observing the wall’s changes in the number of 5 times or even up to 50 times impact (10 times of the national standard). It can be known from the experiment that long wall has large vibration but good integrity. The window wall may fracture easily and is not able to meet the minimum standard requirements of impact resistance when the width is small. It needs to take reinforce measures.

Experimental Research on the Vibration Reduction and Impact Resistance Performances of Offshore Structure Based on Magnetorheological Damper

2008 ◽  
Author(s):  
Zhongchao Deng ◽  
Dagang Zhang ◽  
Xiongliang Yao
Keyword(s):  
Vibration Reduction ◽  
Impact Resistance ◽  
Mr Damper ◽  
Magnetorheological Damper ◽  
Offshore Structure ◽  
Loading System ◽  
Vibration Experiment ◽  
Exciting Forces ◽  
The Impact ◽  
Impact Experiments

This paper presents a new kind of vibration reduction and impact resistance isolator system based on magnetorheological technique, and its experiment results. The vibration and impact experiments were designed using MTS hydraulic loading system. There were many load cases being applied in the experiment with different mass of the model, exciting forces, and controllable electricity of MR damper (Magnetorheological Damper). The experiment results indicate that this isolator system can control the vibration response very well, especially near the natural frequency of the system; and the isolator system has a good performance in the impact experiment too, the response acceleration was evidently reduced, but the characteristic of MR damper was different form its performance in vibration experiment.

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