Traditionally, composite materials have found widespread use in applications where significant weight savings are desired. Aerospace and, more recently, automotive sectors have managed to exploit the highly specific properties of composites to offer lightweight solutions that deliver more efficient aircraft and motor vehicles and help achieve reduced CO2 emissions.
The construction industry is now facing the same needs, but with the added challenge of also delivering the high performance and durability demanded by these heavy engineering tools. Composite materials are generally considered to be more delicate compared to steel and damage can often be difficult to detect. It is, therefore, hard to justify wholesale replacement of the large steel exterior parts of the excavator with lightweight aerospace composites, even though impressive weight savings could be achieved; the vehicles would just not stand up to the same rough handling that JCB customers expect.
There are areas where composites can make an important contribution to shedding weight. The hydraulic actuators can be made using composite cylinders that can reduce the weight of the excavator arm without compromising its durability. In ELSOHA, TWI will help JCB investigate the feasibility of incorporating these new parts and determine what adaptations would be needed to make them a cost-effective solution.
JCB products are generally manufactured as welded steel fabrications due to the harsh operating conditions experienced. Welds can suffer from fatigue and residual stresses, but adhesives offer advantages in these areas and are now in common use in the automotive industry. Adhesive bonding is being investigated in the ELSOHA project as a solution to joining different and potentially new grades of steel to achieve lighter hybrid structures.