A Method for Predicting Wing Crack Propagation Trajectories
A technology of crack propagation and trajectory, which is applied to the prediction of wing crack growth trajectory in specimens with open cracks, and in the field of prediction of wing crack growth trajectory, can solve the problems of large error, complicated mechanical calculation and analysis process, and inconvenient analysis, and achieve Easy to operate, easy to understand, simple method effect
Active Publication Date: 2020-08-18
CENT SOUTH UNIV
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Problems solved by technology
Since the wing crack actually expands in a curve, the simplification to a straight line has a certain approximation, resulting in large errors, and its mechanical calculation and analysis process is complicated, which is not convenient in practical application analysis
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[0034] The scheme of the present invention will be further described below in combination with specific embodiments and accompanying drawings.
[0035] Such as figure 1 As shown, the present invention provides a method for predicting wing crack propagation trajectory, comprising the following steps:
[0036] Step 1. Prefabricate a sample containing open cracks, and control the inclination angle of the cracks to be α;
[0037] Step 2. Under the condition of compression and shear, carry out stress analysis on the tip of the open crack to obtain the stress field at the tip of the crack, and then obtain the crack initiation angle θ of the tip of the open crack. The expression is:
[0038]
[0039] In formula (1), K II 、K I are the type II and type I stress intensity factors of the crack tip, respectively. According to the results of J.Tirosh [2], under the condition of considering different tip curvatures, K II 、K I The expression is:
[0040]
[0041] In formula (2), ...
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The invention discloses a method for predicting a wing crack propagation track, which belongs to the field of rock mass mechanical analysis, and comprises the following steps of: firstly, obtaining tip crack initiation angles of open cracks with different crack inclination angles in a compression-shear state through theoretical calculation in combination with test result correction; On the basis of the relation between the crack inclination angle and the crack initiation angle, determining the wing crack propagation track of the initial crack in the microsection, and then connecting the end points of the two wing cracks to form a new crack, namely an equivalent crack; And taking the equivalent fracture as the initial fracture, continuously determining the expansion of the next micro-section, and so on to obtain the expansion track of the wing fracture. The prediction result is well matched with the test result, and compared with a traditional method for determining the crack propagation track through mechanical calculation, the method can conveniently obtain the wing crack propagation track, and is simple, easy to understand and convenient to operate.
Description
technical field [0001] The invention belongs to the field of rock mechanics analysis, and relates to a method for predicting wing crack propagation track, in particular to a prediction method for wing crack growth track in a sample containing open cracks under compression-shear conditions. Background technique [0002] Rocks in nature form intermittent discontinuous surfaces during geological activities. The existence of discontinuous surfaces leads to strong anisotropy in the mechanical properties of the rock mass, which reduces the stability of the rock mass and brings difficulties to the construction of rock mass engineering. There are many uncertainties, so the research on rock mass with fractures has become the first thing to be solved in engineering construction. [0003] Among them, the fracture failure process of specimens with single cracks is the basis of fracture mechanics research, and its importance is self-evident. During the compression process of the sample ...
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IPC IPC(8): G06F30/20
Inventor 林杭杨横涛曹日红曹平
Owner CENT SOUTH UNIV