Some applications require energy to transfer from one substrate to another and some require the energy to be absorbed or dissipated. The adhesive choice will impact how well a joint transmits energy by connecting substrates or by absorbing energy between substrates.
Usually this refers to mechanical energy, and that’s the main focus below. However there are also cases where an application requires transmission or dissipation of thermal or electrical energy. Adhesives have different thermal and electrical properties, so adhesive selection is just as important in those instances.
A perfect example of transferring energy is the small joint where a golf club head is attached to the shaft. No golfer wants the energy of the swing to dissipate when making contact with the ball, so as much of that energy as possible should be transferred through the use of a rigid adhesive. The same is true when bonding composite drive shafts. As torque is supplied by the engine, efficient energy transfer to the wheels is critical for performance.
An application where it’s preferable to absorb energy would be the side panels on a trailer or box truck. If they were attached with a rigid adhesive the entire structure would vibrate and rattle at every bump in the road, not to mention during a strong cross breeze. Instead, choosing a viscoelastic adhesive or tape can help cushion and absorb some of that energy. Other common examples where energy absorption is desirable include sports equipment pads, tablet computers and car doors.
The design of the joint often coincides with the choice of adhesive chemistry. Comparing the joint design of various assemblies with the adhesive chemistries and manufacturing processes helps narrow down the ideal choice for any given assembly.