切向气流对激光加热金属板非熔化穿孔效应的影响

Abstract

On the basis of elastic bending theory,the bending deflection expression by both quadrate and circinal facula irradiations is deduced for burn-through effect with no-melting of metal heated by a laser caused by tangential airflows.A rupture criterion for burn-through with no-melting is given out by the Mises theory.The study indicates that the material softened by laser heating is the primary mechanism for burn-through effect with no-melting.The maximal deflection of thin plate in the spot area is related to the airflow speed,spot diameter,plate thickness and the elasticity modulus(expression is U2a4/Eh3),the damage temperature is related to the airflow speed,spot diameter and the plate thickness(expression is(Ua/h)2),and the damage threshold under the circinal facula irradiated is higher than that under the quadrate facula.The numerical result indicates that for aluminum alloy shell,the damage threshold of laser energy can decrease much up to 40%-50% under 0.8 Ma tangential airflows,but it can decrease less(about 20%) for a stainless steel shell.The damage threshold decrease under airflows needs more attention.