多夹砂层玻璃钢夹砂管弯曲性能及破坏模式

Bending Performance and Failure Mode of Glass Fiber Reinforced Plastic Mortar Pipe with Multiple Mortar Layers

为研究多夹砂层玻璃钢夹砂管的弯曲性能及破坏模式,自定长缠绕生产的玻璃钢夹砂管上沿环向方向截取弧形管材试样,开展试样凹向和凸向两类加载方式的三点弯曲试验,分别得到两种加载方式下试样的弯曲强度、弯曲弹性模量以及荷载–位移曲线。试验结果表明,玻璃钢夹砂管管材弧形试样在凹向和凸向加载方式下的弯曲强度平均值分别为160.81 MPa和116.41 MPa,弯曲弹性模量平均值分别为7932 MPa和6508 MPa,凸向加载方式更易导致试样发生破坏;凹向试样的破坏模式为多夹砂层的瞬间剪切脆性破坏,而凸向试样呈现出先产生层间裂缝进而砂层沿45°方向出现的渐进剪切破坏模式,加载方式和破坏模式不同是导致弯曲强度和弯曲弹性模量大小差异的主要原因。

In order to study the bending performance and failure mode of glass fiber reinforced plastic mortar pipe with mul-tiple sand layers,the arc-shaped pipe samples were cut along the circumferential direction from the glass fiber reinforced plastic mortar pipe produced by winding fibers of specified length,and the three-point bending tests were carried out with concave and con-vex loading methods.The bending strength,bending elastic modulus and load–displacement curve of the samples under two loading methods were obtained respectively.The experimental results show that the average value of bending strength determined by the concave and convex loading methods of the curved specimen of the glass fiber reinforced plastic mortar pipe are 160.81 MPa and 116.41 MPa,and the average value of bending elastic modulus are 7932 MPa and 6508 MPa,respectively.Convex loading meth-od is more likely to cause damage to the specimen.The failure mode of the concave specimen is the instantaneous shear brittle failure of multiple sand layers,while the convex specimen exhibits the first interlayer cracks and then the sand layer is progressively sheared along the 45°direction,the difference in loading method and failure mode is the main reason for the difference in bending strength and bending elastic modulus.