本文選題：預(yù)裂人字形切槽巴西圓盤 + 動態(tài)擴(kuò)展韌度�。� 參考：《巖土力學(xué)》2017年11期

【摘要】：關(guān)于動態(tài)斷裂的全過程,包括動態(tài)起裂、擴(kuò)展和止裂的報道在科學(xué)文獻(xiàn)中受到日益增長的關(guān)注。研究巖石的動態(tài)擴(kuò)展和動態(tài)止裂,用分離式霍普金森壓桿徑向沖擊大直徑(φ160 mm)的預(yù)裂人字形切槽巴西圓盤(pre-cracked chevron notched Brazilian disc——P-CCNBD)試樣的試驗,測定了大理巖的I型動態(tài)擴(kuò)展韌度,而不僅是動態(tài)起裂韌度。確定的方法是試驗 數(shù)值 解析法,而不是通常的準(zhǔn)靜態(tài)法,因為,大尺寸試樣在動態(tài)試驗中不滿足應(yīng)力平衡條件。裂尖起裂時刻和裂紋擴(kuò)展速度采用應(yīng)變片和裂紋擴(kuò)展計監(jiān)測;將有關(guān)試驗數(shù)據(jù),包括霍普金森壓桿施加在試樣上的的動態(tài)荷載輸入有限元程序,對P-CCNBD進(jìn)行三維動態(tài)數(shù)值模擬,再結(jié)合普適函數(shù)的半解析修正,得到動態(tài)應(yīng)力強(qiáng)度因子的時間歷程。結(jié)果表明,P-CCNBD大理巖試樣的動態(tài)起裂韌度隨加載率的增大而增大,試樣的動態(tài)擴(kuò)展韌度略低于動態(tài)起裂韌度,且擴(kuò)展韌度隨裂紋擴(kuò)展速度的加快而增大。此外,對裂紋擴(kuò)展速度振蕩和擴(kuò)展路徑曲折現(xiàn)象進(jìn)行了分析,討論了P-CCNBD試樣實現(xiàn)動態(tài)止裂的可能性。
[Abstract]:The whole process of dynamic fracture, including dynamic initiation, extension and crack arrest, has attracted increasing attention in the scientific literature.The dynamic propagation and crack arrest of rock were studied. The I-type dynamic propagation toughness of marble was measured by means of radial impact of split Hopkinson compression bar on large-diameter (蠁 160mm) pre-cracked herringbone chevron notched Brazilian disc (P-CCNBDD) specimen.It is not only dynamic initiation toughness.The method of determination is the numerical analytical method, rather than the usual quasi-static method, because the stress balance condition is not satisfied in the dynamic test of large-sized specimens.The crack tip crack initiation time and crack growth velocity are monitored by strain gauge and crack propagator, and the relevant test data, including the dynamic load applied on the specimen by Hopkinson compression bar, are input into the finite element program to simulate the three-dimensional dynamic numerical simulation of P-CCNBD.The time history of the dynamic stress intensity factor is obtained by using the semi-analytical correction of the universal function.The results show that the dynamic initiation toughness of P-CCNBD marble increases with the increase of loading rate, the dynamic propagation toughness of the specimen is slightly lower than that of the dynamic crack initiation toughness, and the propagation toughness increases with the acceleration of the crack growth rate.In addition, the phenomena of crack propagation velocity oscillation and propagation path twists are analyzed, and the possibility of dynamic crack arrest of P-CCNBD specimen is discussed.
【作者單位】： 河南理工大學(xué)能源科學(xué)與工程學(xué)院;煤炭安全生產(chǎn)河南省協(xié)同創(chuàng)新中心;四川大學(xué)土木工程及應(yīng)用力學(xué)系;
【基金】：國家自然科學(xué)基金面上項目(No.51674101,No.41672282) 河南省重點實驗室開放基金(No.S201605)~~
【分類號】：TU45

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