Producing the finest safety equipment for climbers demands continuous product improvement to ensure optimum design, materials and manufacturing techniques.
North Wales based climbing equipment manufacturer DMM produces the innovative and highly acclaimed Deadman. The main section of this lightweight snow protection device is made from aluminium alloy as shown in the illustration.
Driven by the desire to reduce the weight of the Deadman further, whilst maintaining or enhancing its excellent functionality, strength and durability, the company decided to explore the use of carbon fibre composite instead of aluminium alloy.
With the strength requirements of the Deadman clearly defined, DMM was determined to meet these with the lightest possible composite material. They achieved this goal through technical support from TWI's Joining Forces Wales technology transfer programme. It established how the strength of the Deadman would be affected by the thickness of the composite material as well as the way in which the material was made.
R&D work at TWI involved Finite Element Analysis (FEA). This computer-based method is widely used in engineering to study the effects of impact, vibration and thermal or static loads on components and structures. It can simulate and predict stresses, deformation, temperatures and other important parameters to achieve an understanding of strength and in-service performance.
FEA showed the stresses within the Deadman and predicted its strength in relation to the composite's lay-up, ie fibre type and orientation and number of plies (layers) in the composite, including specially positioned reinforcement.
FEA enabled optimisation of the lay-up to provide the most favourable distribution of stresses and best strength-to-weight performance. This work has allowed DMM to proceed safe in the knowledge that the design of their new carbonfibre Deadman exceeds the standard of excellence demanded by the company.