Numerical Simulation On Penetration Behavior Of Concrete Based On Random Aggregate

Concrete is widely used in buildings, bridges and protective structure, etc. The research of concrete penetration is widely focused due to the importance of the concrete application in protective structures. The macro mechanical property of concrete material is determined by mechanical property of meso structure. Therefore, the concrete mesoscopic structure characteristic and mechanical property is one of the important contents of the study on concrete mechanical property. Concrete is considered as a three-phase composite material consisting of aggregate, mortar matrix and the interfacial transition zone between them. At present, the entity model with HJC constitutive relation is used in the concrete penetration simulation. However, the performance of concrete structure is so complicated that cannot completely represented by the entity model. The simulation results are in great difference with the actual results, which lack of reliability. Concrete aggregates are composed of crushed stones, thus concrete aggregates are simulated as random distributed spatial polyhedron to be more close to the reality. The current research of concrete based on random distributed aggregate is mainly in three-dimensional field and some modeling method of three-dimensional aggregate is not perfect. The modeling method of concrete aggregate between two-dimensional and three-dimensional is contributed to the study on concrete mesoscopic mechanics.The main contents in this paper are listed as follows:1. The method of generation and delivery of two-dimensional random aggregate is proposed by random function in MATLAB. Based on that proposed method, the three-dimensional random aggregate generation program is written to generate convex polyhedral aggregate with different volume ratio.2. The parameter data of convex polyhedral aggregate with different volume ratio is extracted to generate three-dimensional random aggregate model by finite element software. And then, the model is meshed by finite element software to establish a concrete model based on three dimensional random aggregate.3. In this thesis, the penetration models of concrete target based on random distributed aggregate with blunt projectile, spherical projectile, different CRH ogive-nosed projectile and penetration angle is established to study the influence of different penetration factors on the penetration resistance of concrete target.4. The penetration model is calculated by the finite element software LSDYNA. The data of penetration depth, residual velocity, acceleration time curve and displacement time curve is extracted and analyzed to obtain the relationship between different projectile, CRH ogive-nosed projectile, penetration angle and penetration resistances of concrete target. For different projectile, the performance of blunt projectile penetration resistance of concrete target is better. For different CRH ogive-nosed projectile, with CRH increasing, the performance of concrete target penetration resistance is worse. For different penetration angle, with the penetration angle increasing, the penetration resistance of concrete target is better.