Numerical Simulation Of Dynamic Mechanical Behavior Of Desert Sand Conorete

Due to its low cost and high strength, concrete is used widely in various engineering fields. It is not only subjected to necessary design load, but also withstands all kinds of dynamic loads. Sand is one of the essential ingredients of concrete, but the sand can not to meet building needs whether in the perspective of the quality, economy or reserves. The west region China has abundant resources of desert sand, if the desert sand can be used for concrete, not only solved the problem of the increasing scarcity of natural fine aggregate, but also ease the current situation of environmental degradation. So the research of desert sand concrete has important practical significance for developing the local economy, enhancing the economic efficiency and improving the ecological environment. Based on the experiment, the article at the meso level, research the dynamic response of desert sand concrete, the main contents and results are as follows:(1) The dynamic response of desert sand concrete with different desert sand replacement ratio was carried out by SHPB equipment, results shows that with the increase of the desert sand replacement ratio, the peak stress of desert sand concrete declines; with the increase of strain rate, the peak stress of desert sand concrete increases; with the increase of strain rate, the damage of desert sand concrete become worse, the number of pieces increases, the volume of pieces deseases.(2)Regarding desert sand concrete as non-uniform composite composed of mortar and aggregate. Building random aggregate model, with Fuller grading curve and Walaraven plane conversion formula to calculate the number of aggregate, a two-dimentional circular aggregate program is designed using APDL language in ANSYS software to simulate the dynamic response of desert sand concrete. The influences of impact velocity, particle size and volume fraction of coarse aggregate and specimen dimension on the dynamic mechanical behavior of desert sand concrete are analyzed. Numerical simulation shows that the peak stress of concrete increases with impact velocity, so desert sand concrete has obvious rate effect; With the enhancement of specimen dimension, the peak stress of desert sand concrete decreases, so desert sand concrete has obvious size effect; With the volume fraction of coarse aggregate, the peak stress of desert sand concrete increases firstly, then declines. When the volume fraction of coarse aggregate is equal to 40%, the peak stress of desert sand concrete is maximum value; Keeping the maximum particle size of 25mm unchanged, with the increase of the minimum diameter of coarse aggregate, the peak stress of desert sand concrete declines; Keeping the minimum particle size of 5mm unchanged, with the increase of the maximum diameter of coarse aggregate, the peak stress of desert sand concrete increases firstly, then declines, when the particle size of coarse aggregate is equal to 20mm, the peak stress of desert sand concrete is maximum value.(3) Simulating the dynamic failure process of desert sand concrete specimens with different desert sand replacement ratio. The influences of desert sand replacement ratio on the peak stress of desert sand concrete are analyzed. Results shows that keep the volume fraction of coarse aggregate unchanged, with the increase of the desert sand replacement ratio, the peak stress of desert sand concrete increases firstly, then declines, when the desert sand replacement ratio is equal to 20%, the peak stress of desert sand concrete is maximum value.