Numerical Simulation Of Dynamic Mechanical Behavior Of Concrete And Reinforced Concrete

Due to its abundant raw materials, low cost, high strength and durability, concrete is used widely in various structural engineering. Concrete is a kind of polyphase and non-homogeneous composite materials. Because of complicated and changeable mechanical property, concrete is still the emphases on which researchers at home and abroad focused. This paper simulates the dynamic mechanical response of polygonal coarse aggregate concrete and reinforced concrete by numerical simulation method. These are following works of this paper:(1) The numerical simulation of dynamic mechanical property of polygonal coarse aggregate concrete under the impact. The concrete was considered as two-phase composite of cement mortar and polygonal coarse aggregate. On the basis of Fuller gradation curve and Walaraven plane conversion formula, a two-dimensional polygonal coarse aggregate random distribution program of concrete was designed by APDL language. This paper make use of ANSYS/LS-DYNA establishing concrete material finite element model in order to analyze the influence of volume fraction of polygonal coarse aggregate, particle size and distribution of polygonal coarse aggregate, specimen dimension and impact speed on the mechanical properties of concrete with crushed stone. Numerical simulation shows the concrete with crushed stone is rate-dependent and size effect. With the enhancement of the volume fraction of polygonal coarse aggregate, the peak stress of concrete increases firstly, then reduces. The maximum value of particle size of polygonal coarse aggregate being kept constant, the peak stress of concrete with crushed stone reduces with the increase of minimum value of particle size of polygonal coarse aggregate. Whereas, the minimum value of particle size of polygonal coarse aggregate being kept constant, with the enhancement of the maximum value of particle size of polygonal coarse aggregate, the peak stress of concrete increases firstly, then reduces.(2) The numerical simulation of dynamic mechanical property of reinforced concrete under the impulsive loadings. This paper simulates the dynamic response of reinforced concrete in the different impact velocity and extract stress-time curves, the peak stress of target board of reinforced concrete and the stress nephogram of dynamic destruction process. Compared with experiment about reinforced concrete, we found the stress wave under impact load of finite element model is better and curves are in consistent with the experimental results. Because the reinforced concrete material are affected by the internal fine structure disturbance, reinforced concrete material show obvious hysteresis effect. With the increase of loading rate, the peak stress of reinforced concrete has obvious improvement. As the target plate position move backwards, the peak stress of reinforced concrete reduce gradually. The difference between peak stress on experiments and numerical simulation are small. It shows that the finite element model and the selection of parameters are reasonable and effective.