نوع مقاله : یادداشت فنی
نویسندگان
دانشکدهی فنی و مهندسی عمران، دانشگاه رازی، کرمانشاه
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
The constant ``F'' is of significant importance when it comes to the design and theoretical understanding of crack expansion under fatigue or impact loads. Even though numerous papers on the failure of materials via the cracked disc have been published, almost no method vis$-\acute{a}$-vis vis the optimization of the shape factor ``F'' has been proposed. Thereupon, this study strives to determine the stress intensity factor (SIF) for the semi-circular disc model under uniform compressive load and also to calculate the optimized shape factor. In this research, inspired by the geometry of the Brazilian disc, the stress intensity factor (SIF) and the optimized shape factor (F) under uniform compressive load have been proposed. In this paper, to assess KI under uniform compressive load, the experimental results of photo-elastic materials and also the finite element results have been employed. The shape factor of the Edge Cracked Semicircular Disk (ECSD) under uniform compressive load can experimentally be tested more conveniently and therefore by altering the value of the factor $\beta$, the optimal shape factor is obtained.The angle $\beta$ varies from zero (purely vertical load) to 10 degrees. Also, the length of the crack changes from 1 to 29 mm. After the carried-out investigations, it can be ascertained that the value for $K_I$ reduces as the angle increases. The reason behind that is the reduction of the tensile area in the edges of the semi-circular disc. Further, in a particular angle, as the crack length increases, $K_I$ initially rises and then, due to the tip of the crack approaching the compressive area of the disc, it undergoes reduction. The'' zero degree'' diagram is considered to be the limit state and is perpetually increasing and it should not be crossed by any other diagram. To achieve the optimal shape factor, the values of ``SIF'' and the length of the normal crack should first angles, the optimum geometric shape factor of the cracked semi-circular disc was determined to be equal to 1.325 at the angle $\beta=2^{0}$.
کلیدواژهها [English]
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