Antiknock Performance And Damage Assessment Of Steel Fiber Reinforced High Strength Concrete Members

In modern society, explosive accidents came up repeatedly, which jeopardize life and property safety of human. As a new type of anti-explosive material, the characteristic research of steel fiber reinforced concrete has been valued a lot, yet the research wasn’t comprehensive. In this research, theory analysis and numerical analysis was used on the dynamic response, damage assessment and collapse resistance performance. Main research and achievements can be obtained as follows:(1) Considering the effects of steel fiber on core concrete with fcR, the modified static stress-strain relations of SFRHSC was used in numerical simulation of steel fiber reinforced high strength concrete filled steel tubular short columns under axial compression load, compared with experimental results, the reliability of constitutive model was verified. Considering rate correlation and the enhancement effect of steel fiber for material, the J-H-C dynamic material model derived from the parameter values by using the test data, provides an appropriate dynamic material model and parameters for SFRHSC component.(2) Considering the effect of steel fibre reinforced and material strength increases under dynamic load, the theoretical dynamic response analysis and calculation of SFRHSC walls are carried based on equivalent one-degree systems, the maximal displacement is calculated. Based on reasonable assumptions, a theoretical formula for limit deformation of walls with large deformation is established by means of using the law of conservation of energy and Lagrange equations. The formula and theoretical analysis are verified by compared with some numerical results. It’s been proved that the formula can satisfy the limit deformation calculation analysis when it’s long load duration.(3) A finite element model method of SFRHSC wall with clamped supported on four sides is developed for simulating dynamic response by using a explicit dynamic finite element analysis program, LS-DYNA, And the method was discussed and verified through correlated experimental studies. The development process of all stress, strain, pressure, and displacement in the dynamic response of SFRHSC walls are analysed, and each dynamic response under different parameters are analysed to reveal the influence law of various parameters. The failure mode of SFRHSC wall based on the scale distance are analysed and summarized. A pressure-impulse damage criterion is defined based on the support rotation, and a numerical method to generate pressure-impulse diagrams is established. Pressure-impulse diagrams and curves fitting formulas for SFRHSC wall are established. Pressure-impulse diagrams established in this dissertation can carry out accurate damage assessments for SFRHSC wall under different blast loads.(4) The anti-collapse performances of SFRHSC slabs under different explosive weight are analyzed. The Damage form and influence factor of SFRHSC slabs based on experiment of literature and numerical simulation are analyzed. The RBF and BP neural network anti-collapse model were established, the calculation of empty register diameter and maximum width of back side break were carried on, compared with measured values, the neural network anti-collapse model is reliable for the analysis and assessment of anti-collapse characteristic of the slab.