船用吊篮高空坠落事故原因分析

船用作业吊篮在距地面20m岛处作业时发生坠落事故。通过断口宏微观观察、化学成分分析、力学性能检测及金相组织检查等，对事故中的断裂螺栓进行检验和分析。对吊篮系统在役情况下的应力分布和安全性进行计算和分析，计算结果表明：事故中M36mm螺栓在正常服役、违章作业、存在微裂纹缺陷等条件下是安令的。对吊篮坠落事故的发生过程进行分析与计算，结果表明：当吊篮系统受到外力作用而失去平衡的瞬间，巨大的剪切载荷造成梁端部M10mm连接螺栓首先剪切断裂，梁坠落过程中M36mm螺栓在冲击、扭转和弯曲应方下发牛断裂，最终整个吊篮系统发生高空坠落。

Analysis on Basket System for Ship Falling Accident

A basket system for ship fell during service at the altitude of 20 m. The failure cause of the fractured bolt was analyzed by fracture and metallographic observation, microhardness testing and mechanical property experiments. The stress distribution and safety of the basket system under service were calculated and analyzed. The results show that the bolt is safe when used under normal condition, or even under the condition of improper operation or with micro cracks. Then, the accident course was analyzed and calculated. It is found that great shear load led to the fracture of the linking M10 mm bolts at the end of the beam at first when the bracket system lost balance suddenly because of unexpected outer load. During the falling course of the beam, the M36 mm bolt fractured under the co-effect of impact, torsion and bending stresses. As a result, the whole basket system fell from the altitude of 20 mm.