Cause of Crack in Connecting Plate of Airborne Optoelectronic Equipment

During the trial production of a certain type of airborne optoelectronic equipment, cracks appeared on the connecting plate of main bearing part of magnesium alloy materials in the equipment after impact test. The causes of cracks in the connecting plate were analyzed by means of macro analysis, chemical composition analysis, metallographic examination and stress strain test. The results show that there were many uncontrollable factors in the manual casting process of connecting plate, which led to a large number of shrinkage defects in the internal stiffeners of connecting plate, affecting the continuity of casting, and reducing the bearing capacity and anti fatigue ability of the part. During the test, under the action of force, the crack source initiated in internal defects, and the crack propagation eventually led to the overload cracking of connecting plate stiffeners.