| Summary: | 碩士 === 國防大學中正理工學院 === 軍事工程研究所 === 95 === To understand the behaviour and properties of concrete at different loading rates is vary important for considering the defense abilities of constructure. The response of concrete in dynamic is very different from which in static. Including trength、modulus of elasticity, behaviour of failure, axies and lateral strain, all of those will change with increasing strain-rate and effect extremely the environment and condition of using concrete in structure. So that, we must have very well comprehension for compression situation of concrete of different strain-rate when studying the behaviour of concrete to endure condition of compression loading.
The objective of this study were performed on both forms of damage theory and materials experiment. For the theory analysis of the relationship of stress and strain are used the continuum mechanics and thermodynamics, for the experiment, was to discuss that the effects of strain-rate on compressive properties of concrete cylindrical specismens 72 mm in diameter and about 146 in length specismens with varied velocity of compression loading with designing the quasistatic loading experimemts in velocity of 0.0217 , and the dynamic loading experimemts in velocity of 1.2 , 25 , 1000 and 7000 . To record the process and characteristics for formation and propagation of cracks and failure of speciments In terms of using a high-speed framing camera.
Experiments indicate that the dynamic increase factors of concrete specimens increase significantly with strain rate, especially on compression loading up to 1000 . The analysis of the comparison between damage model and experiments are well consistence in the range of elasticity.
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