Study On Low Velocity Impact Of Basalt Fiber Composite Laminates

Basalt fiber composite material has the advantages of high strength,light weight,corrosion resistance,good designability,size stability and so on,and has been widely used in construction and other fields.In the actual use process,basalt fiber composite material is always facing the impact load,such as high-rise buildings by wind,dust impact,etc.Under the action of low speed impact,the internal damage of composite material will be imperceptible,and the safety hazard is very big.At this time,basalt fiber composites have various damage types and complex mechanical response laws.The impact resistance of basalt fiber composites is closely related to material type,manufacturing process and layering Angle.At present,scholars at home and abroad have carried out experimental research,theoretical analysis,numerical simulation,etc.but there is still a gap in the understanding of the properties of basalt fiber composites,and the applicability of theoretical prediction model is not enough.Considering the influence of fiber content,layering method,effective impact diameter and other parameters on the impact resistance of basalt fiber composite laminates,30 low-speed impact tests were carried out on the specimens of basalt fiber composite laminates under fixed impact energy,and the experimental results were theoretically deduced and analyzed,and the comparative test rules were summarized.On the basis of the dynamic response and failure criterion theory of low-speed impact of composite materials,combined with the material characteristics and test practice,a stiffness degradation scheme was developed.ABUQUS software was used to establish a numerical simulation analysis model for predicting low-speed impact of composite materials.The main work is as follows:(1)15 single low-speed impact tests were carried out on specimens of basalt fiber composite laminates with different layering angles,different fiber contents and different effective impact diameters.The failure morphology of specimens was observed and the variation rules of energy,displacement,contact force and time were analyzed.The experimental results show that the fiber content,effective impact diameter and layering mode all have a certain influence on the impact resistance of the composites,and the damage caused by a single impact on THE BFRP specimens is relatively insignificant.The higher the fiber content is,the more obvious the buffer energy absorption effect is,the smaller the structural stiffness is,and the weaker the impact resistance is.With the increase of effective impact diameter,the energy absorbed by laminates decreases and the impact resistance becomes stronger.When subjected to the initial impact,the laminates with the layering mode of [0°/45°/90°/-45°] show slightly stronger impact resistance.(2)The basalt fiber composite plate specimens with different layering angles,different fiber contents and different effective impact diameters were subjected to 15 repeated low-speed impact tests until the specimens were destroyed.The failure morphology of the specimens was observed and the variation rules of energy,displacement,contact force and time were analyzed.The experimental results show that the structural damage of BFRP specimens is caused by repeated impact,and the damage phenomenon on both sides is inconsistent.The shape of the damage on the front side is related to the punch,but not to the layup mode,fiber content and effective impact diameter of the specimen,while the damage on the back side expands to ellipse or strip from the punch position to the fiber direction.The smaller the layering Angle,the higher the fiber content,the more serious the reverse damage.(3)When subjected to repeated impact,the higher the fiber content,the weaker the impact resistance of laminates;The larger the effective impact diameter is,the stronger the impact resistance is.When the layering angle is 30°,the impact resistance is the strongest.In the initial impact,the dynamic response of BFRP specimens with different layering modes is similar,but with the increase of impact times,the difference of dynamic curve of impact gradually increases.The larger the layering way,the smaller the impact force;The higher the fiber content,the smaller the dynamic response peak value,the larger the maximum displacement,and the smaller the elastic deformation that can be recovered.The larger the effective impact diameter of the specimen is,the larger the rigidity matrix and the higher the rebound energy are after the same number of impacts.(4)The Hashin failure criterion,on the basis of introducing the theory of stiffness degradation,using ABAQUS software calculation simulation model is established,the basalt laminated composites after impact on the dynamic response process is simulated and analyzed the BFRP laminated plates of the relationship between the peak contact force and impact energy,agreed with the test results.The accuracy of the model is verified.