钢构件上防火涂料破损长度的预测

Prediction of Damage Length of Fireproof Coating on Steel Members

为了提高钢结构的抗火性能,通常采用喷涂防火涂料的方法。防火涂料是脆性材料,在外力作用下容易破坏。为了预测钢构件上防火涂料在外力作用下的破损,采用3D和2D有限元模型对防火涂料和钢构件之间的层间应力进行了分析,得到了层间正应力和层间剪应力沿构件长度和宽度的分布规律,并采用弹性方法进行了验证,结果吻合较好。引入防火涂料破损的最大强度破坏准则和能量破坏准则对钢构件在弯剪作用下的破损长度进行了预测,并对影响防火涂料破损长度的参数进行了分析。研究表明:2D有限元可以准确地预测防火涂料和钢构件之间的层间应力,使用两种破坏准则预测得到的破损长度基本一样。荷载比越大,防火涂料破损长度越长;防火涂料越厚,破损长度也越长。

In order to improve the fire resistance of steel structures,fireproof coating is commonly used on steel members.Fireproof coating is fragile and easily damaged by accidental impact.The interlaminar stress between steel plate and coating under external forces was analyzed through 3D and 2D models to predict the damage level of coating.The distribution of interlaminar normal stress and shear stress were obtained along the length and width of steel members.The models were validated by employing elastic theory method and a good agreement has been found.Two damage criteria,maximum stress and distortion energy,are introduced to predict the damage length of coating under moment and shear force.A parametric study was also performed on two factors which have effects on the damage length of coating.The study showed that 2D model is feasible and reliable to evaluate the interlaminar stress between coating and steel column.There is only minor difference in the damage length predictions by two criteria.The damage length increases with the increase of load ratio and coating depth.