材料疲劳造成的灾难及我们从中吸取的教训

凡尔赛火车相撞(1842年

5月8日下午, 1842, 路易-菲利普一世的生日庆典刚刚在凡尔赛结束. Hundreds of spectators piled into countless train cars, so many that it required two locomotives to pull. As the train was making its way back to Paris, the leading locomotive broke an axle, 导致引擎脱轨. 连锁反应导致许多列车车厢相互堆积并起火, caused by the scattering of the engines’ fireboxes. 大多数估计将55人死于事故和随后的火灾. 当时锁乘客门的普遍做法也可能是一个促成因素. 

凡尔赛火车相撞事故是法国第一起此类事故，并成为世界头条新闻. 事故发生时，人们还没有很好地了解金属疲劳和随着时间的推移而普遍退化的情况, which led to fear and confusion among the general populace. 铁路公司, 政府机构, 学者们都开始仔细研究并从中吸取教训，以防止未来的灾难, 以及恢复公众对年轻的铁路系统的信任，使其成为安全可靠的交通工具. 

威廉·兰金和奥古斯特Wöhler只是多年致力于设计进步的众多研究人员中的几个, 测试, and maintenance of train axles. 正因为如此, 历史学家认为，凡尔赛事故标志着人类对疲劳和疲劳领域的严肃兴趣和研究的开始 断裂力学这使得设计和制造更安全、更耐用的商品和零部件成为可能. 

的 Boston Molasses Disaster, 1919

1919年1月15日，2.300万加仑的油箱装满了 with molasses collapsed in Boston’s North End 社区. Witnesses reported hearing what sounded like gunshots, as the rivets shot out of the 50英尺箱. 的 collapse created a molasses wave up to 25 feet high, traveling at up to 35 mph 在其鼎盛时期. 的 forceful wave damaged steel girders on an elevated railway track swept multiple buildings off of their foundations and flooded countless city blocks. 

随后进行了全面调查，使许多因素浮出水面. 之一 最关键的因素是坦克被忽视和普遍失修的状态 当坍塌发生时. Reports stated that basic leak and pressure tests were neglected to be performed prior to putting the tank in service. 报告还指出 油箱加满油后漏得太厉害，不得不把它涂成棕色以掩盖缺陷. 

Despite this, the tank remained in service. 对坍塌后证据的观察表明，根本原因起源于a附近 在圆柱形储罐底部的人孔盖，环向应力集中的地方 最高. 认为疲劳裂纹是在井盖附近产生的，并逐渐发展为疲劳裂纹 critical length prior to failure. Other contributing factors included fermentation within the 油箱和温度的急剧上升，这两者都可能导致内部 pressure of the tank to rise considerably.

De Havilland Comet Plane Crashes, 1954

德哈维兰彗星是世界上第一架商用喷气客机，由 De Havilland of Great Britain. 的 Comet was the crowning achievement for Britain at the 时间，并进一步提高了他们在世界范围内的航空优势，直到第一次 fatal accidents eventually attributed to metal fatigue. 

1954年1月，美国海外航空公司781航班在空中经历了爆炸性减压 Mediterranean Sea en route to London from Rome. All 35 passengers and crew were killed and all Comet aircraft were immediately grounded. After an extensive search and recovery mission, officials began examining the recovered aircraft. It became clear that the aircraft 飞机在半空中解体，官员们最初认为是发动机涡轮爆炸 造成了事故. Turbine modifications were made to all Comets and the planes were 再次被允许飞行. 

就在被允许飞行几周后，另一架彗星飞机南非航空公司 201航班，在地中海上空经历了爆炸性减压从 罗马到约翰内斯堡. Again, all 21 passengers and crew were killed. 这一事件 导致调查人员质疑他们关于涡轮机爆炸是罪魁祸首的假设 解压缩. 

经过对这两架飞机长达数年的广泛调查，确定是金属 设计缺陷引起的疲劳最终导致了两者的爆炸性减压 实例. 金属疲劳起因于一个用于导航的前窗附近. 几个 contributing factors were observed. First, that the squared window design caused an extremely high-stress concentration at the window’s corners. In fact, calculations revealed 飞机在压力下高达70%的极限应力集中在 corners of the aircraft's windows. Secondly, the supports around the window were 按最初规定用铆钉而不是胶合，而且铆钉孔引起疲劳 cracks to initiate after repeated pressurization cycles. 

从这些事故中得出的结论被用来全面检查航空要求 客舱强度. In addition, sharp points and edges were eliminated in aircraft designs, in an effort to reduce stress 浓度.

亚历山大·L. Kielland石油平台，1980年

On March 27, 1980, 亚历山大·L. Kielland, an oil drilling rig, was stationed in Norwegian 北海的水域. 超过 200 workers were off duty in the accommodations of the vessel when a ‘sharp crack’ was reported. 的 rig suddenly heeled over at a 30° angle. 钻井平台的六根锚索中有五根断裂，只剩下最后一根锚索来支撑钻井平台 巨大的压力水平. 钻井平台在这个位置保持相对稳定的时间很短 直到最后一根电缆断裂，钻井平台完全倾覆入海. 超过 120名工人在翻船中丧生，这是中国发生的最严重的灾难 Norwegian waters since World War II. 

的 investigation that followed was able to piece together the events from that evening and determined that the origin of the collapse was caused by fatigue cracking in one of the structural bracings of the rig. 的 crack was then traced to a small 6 mm fillet weld which connected a non-load bearing flange plate to the bracing. 的 fillet weld had a poor profile and significant cold cracking, which caused a significant reduction in 疲劳强度. 法兰板为 also weakened by significant lamellar tearing, which increased stress 浓度. 周期性应力 experienced by the rig in the North Sea served to further exacerbate the 情况.

逃避火车灾难，1998年

6月3日, 1998, 一列从慕尼黑开往汉堡的高速列车因一个车轮失灵而脱轨, 引发了连锁反应，导致一座桥梁倒塌，十几节火车车厢脱轨. 

A steel tire on car #1 started the chain reaction when it failed, 从火车上被释放了吗, and became embedded in the floor of the first car. As the train passed through a switch, the embedded tire slammed against the guide rail of the switch, causing the guide rail to also embed into the train, which lifted the train's axles 偏离轨道. When the train approached the second switch, one of the derailed wheels struck the switch, 这改变了它的设置. 这导致3号车的后轴被拉到平行轨道上, 使汽车剧烈脱轨, which struck and destroyed the main supports of an overpass bridge. 还有几辆车, 时速120英里, struck the bridge until it collapsed completely, blocking the entirety of the track. 剩下的汽车全速冲向废墟，造成了大规模的连环相撞. 

Overall, 101 fatalities were reported along with nearly 100 injuries. 除其他因素外, 调查人员确定车轮的设计存在缺陷，并且在实施之前缺乏足够的验证测试. 工程师们在轮胎和轮体之间放置了一个橡胶阻尼圈，以减少巡航时的振动. This led to increased fatigue susceptibility in several ways: 

• 车轮转动时，轮胎被压扁成一个椭圆形 每一次旋转(大约50万次在典型的一天 service), with corresponding fatigue effects.
•  In contrast to the pure monobloc wheel design, cracks could also form on the inside of the tire. 
• As the tire became thinner due to wear, the dynamic forces were exaggerated, resulting in crack growth. 
• 轮胎上的扁平斑点、隆起或隆起会显著增加轮胎的 dynamic forces on the assembly and greatly accelerated wear.

其他因素包括维护不当(记录显示，这个特殊的轮子在导致撞车的几次检查中都没有通过), although it was never replaced), overbridge design (wasn’t designed with spans), 以及在车厢车身上使用焊接(导致在撞车时“拉开拉链”)作为灾难的结果, 所有具有类似设计的车轮都被替换为单块车轮.

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