Papers by Keyword: Damage Characteristic

Abstract: A series of plate-impact experiments were performed to study the damage characteristics of incipient spall in ultrapure aluminum (99.999%). Surface profile measurement system based on the axial chromatic aberration was used to measure the cross section of “soft-recovered” samples and reconstruct the metallographic and 3D surface topography. Statistical analyses show that the size distribution, coalescence condition and connectivity factor of the voids are regularly affected by loading conditions. Based on this finding, the mechanisms that control the damage properties and evolution process of dynamic fracture are analyzed in detail. The results of this research offer an experimental quantitative microstructure description of the ductile fracture process.

Abstract: The dispersion characteristics, damage region and destroy results of typical defending materials by pre-fragment warhead using explosively driven were numerical studied by non-linear finite code of LS-DYNA with fluid-structure interaction algorithm, meanwhile, the influence of different detonation types and explosive properties on dispersion characteristics and damage results of kinetic energy rod were analysed. Results show that: 1.fragments disperse symmetrically with greater damage region when center detonation and line detonate are adopted, and the dispersion velocity of fragments reach the maximum when line detonate is used; 2.explosive of higher detonation velocity in favour of improving the initial velocity of fragments, strengthing the damage ability; 3.the penetration kinetic energy of fragments increase with the decrease of axial angle between fragment and damage target.

Abstract: Through analyzing the typical damage characteristic of bridges and corresponding earthquake disaster data in several destructive earthquakes at home and abroad, the law of earthquake damage on bridges has been summarized. Aiming at current aseismatic research and design of highway bridges, further research direction in the field of bridge seismic has been pointed out. In order to improve the seismic behavior of future bridges, some design points to attention have been proposed based on seismic conceptual design and aseismic measures of bridges.

Abstract: Honeycomb sandwich structures are generally designed to carry flexural loads. However, mechanical properties can be influenced by accidental impacts, or service conditions. Thus a nondestructive detection testing is desired for them. In contrast to many conventional nondestructive evaluation (NDE) techniques, acoustic emission (AE) technique permits continuous damage inspection, classification and identification of failure modes in real time. In this work the fracture process of steel honeycomb sandwich beams has been investigated by in-situ AE technique. Pre-cracks were made both for L-direction and W-direction specimens subjected to three-points bending loads. Damage initiation sites were observed in the vicinity of the crack tip. A series of curves among the AE hits, AE amplitude, AE energy and loading time were obtained. Damage characteristics were discussed based on the above parameters. The results indicate AE characteristic parameters can reflect the damage and failure process of specimens. A good agreement was found between the experimental and analytical results.

Abstract: Introduced after the Wenchuan earthquake, the situation of teaching buildings collapsed, buildings destroyed by the actual picture of the location and characteristics of some typical building damage, building damage arising described several major reasons put forward the views of housing and construction reinforcement, stress the seismic design and the importance of project quality management.