Design analysis of a prototype concrete mixer

A mobile batching and mixing prototype, the ‘Cannon Concrete’ mixer, has been developed to service a market requiring small to medium concrete volumes. The designer of the truck, Robert Cairns, has experienced problems with the operation of the truck and mixer and a design analysis was required to determine the nature and details of the problems experienced, locate the source of the problem and provide a solution. The primary objective was the weight of the truck. Thought at first to be a product of over engineering, further analysis exposed larger problems than first imagined and the direction of the solution procedure changed to accommodate these problems. An analysis of the entire truck uncovered design problems that were addressed to better prepare the truck for the operations and duty cycles expected of it. Further analysis involving finite element modelling was performed to reduce weight in the mixer body and investigate the effects of proposed modifications. Loading conditions were specified and care was taken to model the prototype mixer body closely on the operating conditions experienced by the truck during its ordinary and extra-ordinary duty cycles. The results were verified using analytical calculations and design modifications based on the correlation of data gathered. All stress distributions and other analytical results are provided for each finite element analysis.