Adhesives can offer many advantages over mechanical joining methods including:
- Adhesives are particularly suitable for joining two or more dissimilar materials together
- Like welded joints, adhesives are a lightweight joining method
- Adhesives are largely recyclable and are easily broken down if heated
- Can be used in conjunction with a mechanical joining method to reinforce and strengthen a joint
- A disadvantage of adhesives is that the chemicals used are potentially extremely harmful to workers who can come into contact with the substance before manufacturing or during the curing process.
When designing joints that will use adhesives as a bonding agent, engineers must take the expected loads and required performance levels into account as fracture and failure of the bonded joint is possible under certain circumstances. Factors such as excessive strain or loading, fatigue, or the introduction of solvents can dissolve or weaken the adhesive leading to potential failure of the joint. Finite element analysis can be used to predict the performance of a given joint but requires accurate material properties for the adhesive once it has successfully cured.
Adhesives are extremely common throughout many products from vehicle and aircraft interiors to packaging applications but advances have allowed adhesives to be used in a structural capacity. Their high strength allows adhesives to bond metallic together with the joint often proving stronger than the components being bonded. When developing lightweight thermoset components such as carbon composites, adhesives are used to bond the different ply layers together and therefore play an extremely important part in determining the relative strength of the product and its performance characteristics.