Visual Testing (VT) Practice Exam

Which factor can produce service-induced discontinuities in bolting systems?

1. vibration

2. over-tensioning

3. corrosion

4. all of the above

The correct answer is: all of the above

Service-induced discontinuities in bolting systems can arise from a variety of factors that affect the integrity and performance of the bolts and their connections. Each of the factors listed contributes to the risk of failure in distinct ways. Vibration can lead to loosening of bolts over time, which may create gaps or misalignments in the bolted joint. This dislocation can result in uneven distribution of loads and ultimately lead to a failure of the connection if not monitored or managed adequately. Over-tensioning occurs when bolts are tightened beyond their designed load capacity. This excessive force can cause deformation or even fracture of the bolt material, leading to a loss of preload and the potential for joint failure. The structural integrity is compromised, and service-induced discontinuities can develop as a result. Corrosion is another critical factor, as it can gradually weaken the material properties of the bolts. This process can lead to pitting, material loss, and the overall degradation of the bolted connection. Corrosion can also initiate stress concentration points that might become sites for failure under load. Considering these factors together, service-induced discontinuities can indeed be produced by all of the mentioned causes—vibration, over-tensioning, and corrosion—highlighting the importance of diligent maintenance and