One day, while doing his weightlifting routine on the exercise ball in the sauna, the exercise ball exploded, sending Leo onto the ground in an awkward position, with the 200 pound barbell landing on top of his shoulder. Leo’s shoulder was separated and required surgery to repair the damage.
Many considerations are included in a valid engineering design process. Typically decisions that provide for safe service and expected reliability in the given component or structure are the most critical. Determining the numerical value of an appropriate safety factor (or factor of safety) during design is vital to achieving mechanical or structural integrity.
It is essential when beginning a root-cause failure analysis involving metallic materials to collect and maintain the as-found physical evidence properly prior to detailed examinations. This has two objectives. In all cases collecting and protecting the evidence in its undisturbed condition provides the best opportunity to derive meaningful good results from the subsequent analyses. Secondly, in a legal proceeding lack of attention to these matters can produce the accusation of spoilation of evidence. As a minimum this will cause presentation problems for the offending party in the suit. At worst such deficiencies by that party may cause the case to be thrown out.
Rail residual stress distributions can be complex and variable in nature, as different manufacturing techniques produce varying stress magnitudes and distributions. To evaluate the effect of residual stresses on rail integrity, an analysis technique was sought that could quantify the effect of these stresses on web crack propagation.
A severe personal injury incident occurred as a recreational fishing boat was approaching a dock at approximately 20 mph after a day on the water. The large outboard engine (75 HP) on the stern of the boat struck a fixed underwater obstruction, flipped into the boat while still running and amputated the hand of a passenger seated near the engine.
During normal operation, the arm on an automatic wafer test station failed. Root cause failure analysis determined that the drive shaft on the right angle gear motor used to raise and lower the manipulator arm had failed first.
This grinding wheel was part of a product liability and personnel injury case. It was claimed that the subject wheel had unexpectedly failed (i.e. flown apart) and an escaping piece had hit the plaintiff in the face causing serious injuries. According to the user, the grinder with the wheel was purchased approximately one hour before the grinding wheel failure.