Although bolted connections containing nuts can be dismantled when needed, they also come with the disadvantage of potentially coming loose unexpectedly. Bolted joints are a vital component to the proper and safe operation of many products and structures in various industries, including manufacturing, power generation, transportation, mining, and more. At Peak innovations Engineering, we offer bolted joints testing and analysis services to help ensure your fastener connections operate optimally without failing, including by loosening.
Some of the ways nut and bolt loosening can occur include:
1. Temperature Changes
When temperatures drop in colder climates, the metal of the joint connection contracts, forcing the fastener outward, and causing it to loosen.
2. Frequent Use of Equipment
Repeated use of machinery, particularly if it is handled roughly, can cause bolts to loosen a little bit at a time with each use of the equipment.
3. Bearing Weight
Nuts and bolts are more likely to come loose when the equipment they are a part of bears higher load. Also, if the weight carried by the equipment routinely shifts position, bolts affected by the weight may have a tendency to loosen over time.
4. Under-tightening
A bolt that is under-tightened starts out loose. Therefore, from the outset it possesses insufficient clamp force to keep the joint together. This may result in slippage sideways between the sections, adding additional shear stress on the bolt that can cause breaking failure.
5. Over-Tightening
If a bolt is tightened too much, the bolt may be stripped, leading to failure.
6. Vibrations
If a bolt is subjected to vibrations over a period of time, this can lead to side-to-side movement of the thread, resulting in bolt loosening.
7. Shock
Mechanical shock to a bolt or joint can occur as a result of alternating or dynamic loads from machinery of various types, causing the slippage of bolt threads relative to the joint threads. This can ultimately result in bolt loosening.
8. Embedding
Engineers must specify proper tension on a bolt to allow a period of time to occur in which the bolt tightness reduces to a certain degree. This relaxation of the tightness is due to micro-embedding of the bolt head and/or nut into the surface of the joint. It can happen with hard, polished materials and soft materials like composites. The embedment of the joint can result in a reduction on the clamping force if the joint is improperly designed or if the required tension was not achieved in the bolt at the beginning.
Contact Us for Bolt Loosening Analysis
To learn about our bolt loosening analysis and other testing services, give us a call today at 815.420.3802 or reach us through our contact form.
