Optimal hole shape for arrest of longitudinal shear crack

Рассматривается задача об отыскании оптимальной формы отверстия в вершине трещины продольного сдвига. Искомая форма отверстия удовлетворяет условию минимальной концентрации напряжений на его контуре. Исследуется влияние отверстия оптимальной формы на торможение трещины. Дается критерий и метод решения задачи по предотвращению хрупкого разрушения тела, ослабленного прямолинейной трещиной продольного сдвига. Используется минимаксный критерий. Получено условие хрупкого разрушения. The problem of finding optimal hole shape at the tip of a longitudinal shear crack is considered. The desired hole shape satisfies the condition of the minimum stress concentration on the contour. The effect of the optimal hole shape on deceleration of a crack is studied. A criterion and solution method for the problem of preventing brittle fracture of the solid weakened by rectilinear longitudinal shear crack is given. The minimax criterion is used. The brittle fracture condition is obtained.

Failure Analysis at Stem Valve Fire Hydrant in LNG Plant

Hydrant is one of fire extinguisher fix system that use pressure water and flowed through the pipes and fire hose. There are more 250 Hydrant in this LNG Plant and based on finding at the field, many stem valve of outlet hydrant in fracture condition, therefore the author wants to analyze about the problem from this material, this reserch aims to find out root cause dan conduct failure analysis, method of reserch that conducted is visual check to predict possible cause from failure of stem valve fire hydrant and then conducted fractographic analysis to find out what type of fracture that happen to this material and Tensile Strenght Test to Find out the the actual strenght of the material

Experimental Analysis of the Damage Zone around Crack Tip for Rubberlike Materials under Mode-I Fracture Condition

Studying the deformation and fracture properties of soft materials can not only provide insight into the physical mechanisms underlying their superior properties and functions but also benefit the design and fabrication of rubberlike materials. In this paper, an application of the experimental digital moire method to determine the damage zone around crack tip for rubberlike material is presented. The measurement principles and the basic procedures of the method are explained in detail. The in-plane defomation distributions of crack tip fields under Mode I fracture condition are measured. In addition, the deformation of crack tip fields in the damage zones is also analyzed using the sector division mode. Finally, an analysis of the damage zone is proposed to describe crack-tip fields in rubber-like materials with large deformation.