钢-ECC组合梁高温冷却后受剪性能研究OA北大核心CSTPCD

To investigate the influences of temperature and cooling mode on the shear performance of steel-ECC composite beams after high temperature,static loading tests were carried out on four steel-ECC composite beams after high temperature and one normal temperature counterpart.The crack propagation law,failure mode,residual bearing capacity and deformation of steel-ECC composite beams were explored after high temperature.The results show that cracks are characterized by multi-crack cracking and dense distribution after high temperature.With the increase of temperature,the number and width of cracks increase,and the crack depth deepens after wet water cooling.The failure mode of steel-ECC composite beams is shear failure both at room temperature and after high temperature.After 200 ℃ high temperature,the steel-ECC composite beams still have good ductility,but after 400 ℃ high temperature,the ductility of the test beams cooled by wet water decreases significantly.After high temperatures,the residual bearing capacity of steel-ECC composite beams decreases,and the cooling method within 200 ℃ has little influence on the residual bearing capacity.At 400 ℃,the residual bearing capacity after wet water cooling is significantly smaller than that after natural cooling.At 400 ℃,the residual bearing capacity after natural cooling and wet water cooling decreases by 8.7％and 25.7％respectively.The cooling method has a significant effect on the initial shear stiffness of steel-ECC composite beams.The initial shear stiffness of steel-ECC composite beams increases after wet water cooling but decreases after natural cooling.Using the transient heat conduction analysis module in ABAQUS software,the temperature field of steel ECC composite beams was simulated,and the plastic damage model was used to analyze the whole process of thermal mechanical coupling of steel ECC composite beams,and the finite element model was established.The prediction results of the model are in good agreement with the load-displacement curves obtained from the test,and further parametric analysis was carried out using the finite element model,it is found that compared with natural cooling,the shear bearing capacity of steel-ECC composite beams increases little with the increase of wing thickness and strength of steel after wet water cooling.