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Component Failure in Road Traffic Incidents and Accidents
Published in Colin R. Gagg, Forensic Engineering, 2020
The car is the most common cause of sudden death and injury in most countries of the developed world and the developing world. Even if no personal injury is involved, damage to cars can be substantial and investigation of the cause or causes would generally follow. The usual reason for investigating the failure of a component found to be broken after a road traffic accident is to ascertain whether the component was broken in the trauma of collision or had suffered some kind of prior mechanical failure that caused the vehicle to go out of control. In the first instance, driver error or freak road and weather conditions might be held responsible. In the second instance, it is essential to ascertain the mode and cause of failure in order to establish where and with whom responsibility might rest. For example, failure might have resulted from a manufacturing or assembly fault, or mechanical malfunction due to wear, or some progressive weakening such as fatigue or corrosion. If the cause turns out to be mechanical, then it is essential to take into account the recent servicing history of the vehicle and what adjustments might have been made shortly before the accident occurred, for example, over-tightened wheel bearings, loose unions and a whole gamut of faults stemming from careless or unskilled maintenance.
Design of the speed governors for hydraulic turbines by Amesim
Published in Nicolae Vasiliu, Daniela Vasiliu, Constantin Călinoiu, Radu Puhalschi, Simulation of Fluid Power Systems with Simcenter Amesim, 2018
Nicolae Vasiliu, Daniela Vasiliu, Constantin Călinoiu, Radu Puhalschi
The main redundant designs used in the field of hydraulic and pneumatic systems can be split into active redundancy and passive redundancy. In the case of passive redundancy, only one system is working at a given time. When the main system malfunctions, the backup system takes over. The malfunctions are detected by constant supervision of the active system. For this type of redundancy, it is important that the backup system has a greater operational safety than the main system and that the supervision system does not malfunction. These types of systems have several disadvantages, such as the time needed to activate the backup system, the backup system needs to be as large as the main system to accomplish the operating requirements (force, torque, etc.) are met. Active redundancy has two or more systems operating at the same time. The tasks are split between them, the output of the actuators being a sum of all forces. When a malfunction occurs, the damaged system is disconnected and the operation is taken over by the functional system. An example of a passively redundant control system will be built for a simple electrohydraulic servomechanism (Figure 9.1.36). The system’s response at a step input can be seen in Figure 9.1.37.
Bringing Building Automation Systems Under Control
Published in Barney L. Capehart, Timothy Middelkoop, Paul J. Allen, David C. Green, Handbook of Web Based Energy Information and Control Systems, 2020
Reduced downtime caused by mechanical equipment failure.—The use of Infometrics allows systems and equipment to operate under near-optimal conditions for extended periods of time. In addition, equipment and component malfunctions are diagnosed and remedied before catastrophic failure occurs. As a result, equipment life is extended, fewer replacements are required, and replacement costs decline. Furthermore, better diagnostic information enables support staff to more quickly and effectively repair equipment and components.
Fault feature and diagnostic method of bending micro- deformation of crankshaft of piston engine
Published in Nondestructive Testing and Evaluation, 2020
Zhilong Gao, Hanjiang Song, Yongdan Chen, Jinjie Zhang, Zhinong Jiang
Therefore, many researchers have focused on failure analysis of crankshaft of piston engine crankshafts. Lucjan Witek et al. [1]. studied the stress state of the crankshaft during the working cycle and analysed the crankshaft crack failure of a diesel engine. Using the finite element method, the root cause of the failure was found to be the fatigue of the material. In addition, failure investigations of diesel engines crankshafts have been conducted in studies [2–5] that showed many different types of fault cases, including fracture, abnormal vibration and teeth fracture of the crankshaft gear. These faults were analysed through chemical composition, mechanical properties, macroscopic features, microscopic structure and theoretical calculation methods. The main reasons for these malfunctions were fatigue fractures, insufficient strength, poor design and deficient assembly.