The Effect of Chemical Corrosion on Mechanics and Failure Behaviour of Limestone Containing a Single Kinked Fissure

This study concerns the influence of chemical corrosion and geometric parameters on the macroscopic damage characteristics of brittle limestone containing a kinked fissure under uniaxial compression. The specimens are prepared in chemical solutions with different NaCl concentrations and pH values. The acoustic emission (AE) technique is adopted to detect the inner distortion of the failure behaviour. The physical process of the crack coalescence of kinked fissures is synchronously captured by a high-speed camera. Seven failure patterns are identified based on the final failure mode and the failure process. Furthermore, the stress intensity factor of kinked cracks under chemical corrosion is obtained by a theoretical analysis. Chemical erosion with an acidic solution has a relatively strong effect on the compressive strength of the tested specimen, while the initial crack angle is not affected by short-term chemical corrosion.

Investigation of Systems Weakened by Kinked Cracks

Прочность летательных аппаратов любых типов — важнейший вопрос безопасности полетов. Наличие скрытых дефектов в материале существенно влияет на прочность при различных нагрузках. Важными характеристиками прочности материалов с дефектами являются скорость и направление роста трещины, а также величина критической нагрузки (коэффициента интенсивности напряжений), при которой начинается рост трещины. В данной работе исследуется трехмерная упругая среда, ослабленная системой плоских трещин и одной трещиной с изгибом. В качестве численного метода был выбран метод граничных элементов, а именно метод разрывных перемещений. Код реализован на C++. Было проведено сравнение с известными аналитическими результатами. Изучено поведение трещин при изгибе при различных нагрузках. Structural strength of aircraft is a key aspect of flight safety. Hidden defects in the material significantly affect its strength under various loads. The crack growth rate and direction, and the crack growth threshold load (stress intensity factor) affect the strength of the damaged material. This study investigates a 3D elastic structure weakened by a system of flat cracks and a kinked crack. The numerical method used was the boundary element method, specifically, the displacement discontinuity method. The code was developed with C++. The results were compared against the available analytic results. The behavior of cracks under bending and a range of loading conditions was studied.