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（太原理工大學(xué)建筑與土木工程學(xué)院， 太原 030024）
［摘要］為研究往復(fù)荷載作用下網(wǎng)架平板支座超低周疲勞破壞，設(shè)計了長圓孔平板支座試件。在進行了平板支座大位移往復(fù)加載的超低周疲勞試驗后，對錨栓破壞過程、變形特征、宏觀斷面特征展開研究。試驗結(jié)果表明：平板支座在往復(fù)加載過程中，錨栓受到拉-彎雙重作用產(chǎn)生不可恢復(fù)的塑性變形并逐漸積累成為試件的“薄弱”區(qū)域；隨著根部裂紋產(chǎn)生并在加載過程中不斷擴展，在錨栓開裂處產(chǎn)生應(yīng)力集中最終發(fā)生疲勞斷裂；平板支座錨栓斷后的伸長率與縮頸率能直觀反映其變形范圍與塑性損傷累積程度；錨栓斷口表面沿加載方向存在兩個裂紋源，斷面可見半月形貝紋線，斷面中間區(qū)域比較粗糙，錨栓斷口均呈現(xiàn)明顯的疲勞源區(qū)、擴展區(qū)和瞬斷區(qū)，具有疲勞斷口的宏觀基本特征，屬于典型的疲勞破壞。
［關(guān)鍵詞］網(wǎng)架結(jié)構(gòu)；超低周疲勞試驗；平板支座；錨栓；破壞特征
中圖分類號：TU391文獻標(biāo)識碼：A文章編號：1002-848X(2021)04-0119-05
Experimental study on ultra-low cycle fatigue failure of anchor bolt for plate bearing of grid under reciprocating load
ZHANG Ziqiang, LI Haiwang, SONG Xiayun, WANG Xingyu
(College of Architecture and Civil Engineering, Taiyuan University of Technology, Taiyuan 030024, China)
Abstract:In order to study the ultra-low cycle fatigue failure of plate bearing of grid under reciprocating loading, long circular hole plate bearing specimens were designed. After the ultra-low cycle fatigue test of plate bearing under large displacement reciprocating loading was carried out, the failure process, deformation characteristics and macroscopic section characteristics of anchor bolt were studied. The test results show that in the reciprocating loading process of plate bearing, the anchor bolt is subjected to the dual action of tension and bending to produce irreparable plastic deformation and gradually accumulate into a “weak” region of the specimen. With the initiation of root crack and the continuous propagation in the loading process, the fatigue fracture occurs when the stress concentration occurs at the crack of anchor bolt. The extension rate and necking rate of plate bearing anchor bolt after breaking can directly reflect the deformation range and the accumulation degree of plastic damage. There are two crack sources along the loading direction on the fracture surface of anchor bolt. The middle area of the fracture surface is rough, and the half-moon-shaped shell lines can be seen in the fracture surface. The fracture surface of anchor bolt shows obvious fatigue source zone, expansion zone and transient fracture zone. It has the macroscopic basic characteristics of fatigue fracture and belongs to typical fatigue failure.
Keywords:space truss structure;ultra-low cycle fatigue test;plate bearing;anchor bolt;failure characteristics
*國家自然科學(xué)基金(51578358)。
作者簡介：張子強，碩士，助理工程師，Email：735325723@qq.com；通信作者：李海旺，博士，教授，博士生導(dǎo)師，Email：lhwtut@126.com。
