MATERIALS: FATIGUE

MATERIALS

Fatigue

Our material scientists frequently consult on the damage or failure of metallic components and machine parts. Our strength in material sciences, and history in consistently resolving metal related claims are well applied to civil construction, finished goods production, and sea shipping related incidences. We are also experts in a range of materials testing, and the use of various laboratory techniques and instruments to do so.

Cyclic loading of materials can weaken (fatigue) them over time, which in the case of mission critical or load bearing structures can have dramatic and far reaching consequences.

The levels of any force loading on a structure can vary both in their time and extent, as can the consequences of such loads, with some structural changes taking rapid onset while others may advance more gradually.

All anticipated forces and a proper safety margin to handle them should be considered at the design stage through various means including computer modelling, and failure modes and effects analysis (FMEA). AMA engineers, material scientists and naval architects are able to provide valuable input at this early stage so that structures and their constituent parts operate safely, as intended and for a long life.

In the unfortunate event of an unplanned material failure taking place, AMA experts are able to provide input on the likely cause of failure and other contributing factors. Our experts can assist your team to mitigate losses, defend against potential claims and commercial or legal consequences, as well as to provide expert evidence that enables pursuit of other parties.

By thorough investigation we can provide advice on:

  • suitability of designs and the manufacturing process
  • quality and appropriateness of materials used in the construction process
  • the design projected (versus actually encountered) static and dynamic forces
  • maintenance and inspection protocols used or needed
  • manufacturing or latent defects
  • causation of failures and culpability

Case Study:  Crane Lifting Wire Failure

While in use and under load, a crane wire failed leading to crane collapse, with additional damages to valuable items being lifted at the time and third party vehicles under the collapse area of the crane.

Wire samples were testing under standard GB 8918 using industrial load cell and test frame. AMA represented the operator of the crane, who was being sued by the owner of the crane on the basis of misuse leading to accident.

During testing the wires demonstrated failure at a level above their design limit, which the owner stated was clearly showing the lifting wire had not been causitive.

The fracture of the wire faces showed mostly ductile and rapid failure tells, as noted by cap and cone fracture surfaces with dimpled appearance. Some of  the fracture surfaces were smooth in nature from what is likely rapid fracture and ends formed into wire bouquet.

Ordinarily such compelling evidence would have ended the debate, however AMA were able to demonstrate the wires had internal corrosion with corrosion product visible in the wire valleys, and other tells for preexisting excessive wear that included wire flattening and fractures above allowable limits. Based on evidence we provided, the operator was able to successfully counter argue that the wire condition was such that it ought to have been replaced before the accident, and this failure was the more likely mechanism for fracture initiation.

AMA Provided: –

  • Material scientists (metallurgical experts)
  • Mechanical engineers (operational experts)

Why not give us a call now to see how we could help you

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