Instrumented experiments were conducted in concrete models to study the explosion-induced radial strain and fracture effect of rock-like media under confined explosion with a charge of cyclonite. As a charge was explo...Instrumented experiments were conducted in concrete models to study the explosion-induced radial strain and fracture effect of rock-like media under confined explosion with a charge of cyclonite. As a charge was exploded, two different radial strain waves were sequentially recorded by a strain gage at a distance of 80 mm from the center of charge. Through the attenuation formula of the maximum compressive strain(εrmax), the distribution of εrmax and its strain rate（ ） between the charge and gage were obtained. The effect of the two waves propagating outwards on the radial fracture of surrounding media was discussed. The results show that the two waves are pertinent to the loading of shock energy （Es） and bubble energy （Eb） against concrete surrounding charge, respectively. The former wave lasts for much shorter time than the latter. The peak values of εrmax and of the former are higher than those of the latter, respectively.展开更多
Two types of experiments were designed and performed to evaluate the adhesive bond in metal foam composite sandwich structures. The tensile bond strength of face/core was determined through the flatwise tensile test ...Two types of experiments were designed and performed to evaluate the adhesive bond in metal foam composite sandwich structures. The tensile bond strength of face/core was determined through the flatwise tensile test （FWT）. The test results show that the interfacial peel strength is lower than the interlaminar peel strength in FWT test. The mode I interracial fracture toughness （GIC） of sandwich structures containing a pre-crack on the upper face/core interface is determined by modified cracked sandwich beam （MCSB） experiment. It is found that the crack propagates unsynchronously on the two side of the specimen and the propagation of interfacial debonding always stays on the face/core interface during the MCSB tests. In order to simulate the failure of metal foam composite sandwich structures, a computational model based on the Tsai-Hill failure criterion and cohesive zone model is used. By comparing with experiment results, it can be concluded that the computational model can validly simulate the interracial failure of metal foam composite sandwich structures with reasonable accuracy.展开更多
文摘Instrumented experiments were conducted in concrete models to study the explosion-induced radial strain and fracture effect of rock-like media under confined explosion with a charge of cyclonite. As a charge was exploded, two different radial strain waves were sequentially recorded by a strain gage at a distance of 80 mm from the center of charge. Through the attenuation formula of the maximum compressive strain(εrmax), the distribution of εrmax and its strain rate（ ） between the charge and gage were obtained. The effect of the two waves propagating outwards on the radial fracture of surrounding media was discussed. The results show that the two waves are pertinent to the loading of shock energy （Es） and bubble energy （Eb） against concrete surrounding charge, respectively. The former wave lasts for much shorter time than the latter. The peak values of εrmax and of the former are higher than those of the latter, respectively.
基金supported by the Major State Basic Research Development Program of China(973Program)under the contract No.2006CB601206
文摘Two types of experiments were designed and performed to evaluate the adhesive bond in metal foam composite sandwich structures. The tensile bond strength of face/core was determined through the flatwise tensile test （FWT）. The test results show that the interfacial peel strength is lower than the interlaminar peel strength in FWT test. The mode I interracial fracture toughness （GIC） of sandwich structures containing a pre-crack on the upper face/core interface is determined by modified cracked sandwich beam （MCSB） experiment. It is found that the crack propagates unsynchronously on the two side of the specimen and the propagation of interfacial debonding always stays on the face/core interface during the MCSB tests. In order to simulate the failure of metal foam composite sandwich structures, a computational model based on the Tsai-Hill failure criterion and cohesive zone model is used. By comparing with experiment results, it can be concluded that the computational model can validly simulate the interracial failure of metal foam composite sandwich structures with reasonable accuracy.
