Experimental Study On The Axial Compression Performance Of Pultruded GFRP Square Pipe

Steel has always been one of the main materials for civil engineering.With the development of national infrastructure,traditional steel faces problems such as corrosion and metal fatigue in the project,and subsequent maintenance has cost a lot of money and manpower.In order to solve the above problems,there is an urgent need for a material replacement or partial replacement of steel in engineering applications.Fiber-reinforced composite materials have high specific strength,specific stiffness,corrosion resistance,simple maintenance and good designability,and are ideal alternative materials.In this paper,the performance of pultruded GFRP square tube is tested and studied.Taking the pultruded GFRP square tube as the main research object,the material performance test is carried out in accordance with relevant specifications.On this basis,the influence of the width-thickness ratio on the axial compression performance of the pultruded GFRP square tube is studied,and the corrosive environment is drawn down.Axial compression ultimate load test of extruded GFRP square tube.By comparing and analyzing various test data,failure forms and curve changes,studying the mechanical properties of pultruded GFRP square tubes,the following conclusions are drawn:1.Through the material performance test,the basic mechanical performance parameters of the tested materials are obtained.The results show that the pultruded GFRP material has obvious anisotropy,and the mechanical properties of different fiber directions have significant differences,and the fiber is the main force.The unit is a typical brittle material.2.Through the axial compression test of a total of 35 specimens with 7 width-thickness ratios,the failure form,ultimate load,load-deformation curve and stress-strain curve of the specimen are obtained.The results show that there are four failure modes of pultruded GFRP square tubes;the stress-strain curve of the test piece basically follows linear elasticity before failure;the change of the width-thickness ratio will affect the ultimate load and failure mode of the test piece.3.In the corrosion resistance test,by analyzing the surface characteristics,microscopic characteristics,corrosion mechanism and axial compression performance test of the specimens with different cross-sectional dimensions,the following conclusions are drawn:alkaline environment,chloride salt environment,with the increase of time The color,gloss,and finish of the surface of the test piece will change,and the surface will crack and fall off.Both environments will cause the performance of the pultruded GFRP square tube to decrease and the load to decrease.And with the increase of time,the downward trend becomes more obvious;for the same cross-sectional size,the alkaline environment has the greatest impact on the performance of GFRP;when the wall thickness is 4mm,it has good corrosion resistance while ensuring local stability.Figure 44 Table 21 Reference 28...