Structural Analysis and Redesign of a L90 Front Axle Casing

Abstract: This thesis was commissioned by Volvo Construction Equipment (Volvo CE) to redesign the front axle casing of their L90 wheel loader to be more in line with their larger wheel loaders. The current L90 front axle casing consists of two parts bolted together in the middle. However, the current assembly process is cumbersome, and as such, Volvo CE wants to determine if a one-piece front axle casing can be implemented into their L90 wheel loaders. Volvo CE’s larger wheel loaders such as the L120 currently have a one-piece design for the front axle casing and can serve as template. This thesis aimed to determine if it was possible to create a one-piece axle casing for the L90 and provide an example of how it would look like. Additionally, the suggested design would need to meet all of Volvo CE’s performance requirements and be on par with the current L90 front axle casing.  The methodology used to develop the redesigned axle casing consisted of performing different finite element analyses (FEA) in Ansys Mechanical to evaluate the casing’s performance. The analysis was preformed using Volvo CE’s guideline and performance criteria in order to determine what areas in the redesigned axle required further adjustment. Additionally, the redesigned casing would be compared against the current L90 casing. This would determine if the redesigned axle could be realistically implemented into a L90 wheel loader.  Applying this methodology led to three different iterations of the axle casing design. Each design iteration following the first one led to improvements in the casing’s mechanical performance. The third and final iteration was able to meet all of Volvo CE’s static and fatigue requirements. The stresses for the redesigned axle casing are, on average, 13% lower than that of the current axle casing at key points around the casing’s ribs. However, the tolerances required to manufacture the redesigned axle casing where slightly higher than the current L90 casing. Nevertheless, the tolerances required to manufacture redesigned axle can be realistically met by a foundry. This thesis was able to provide a plausible redesign that can be implemented in Volvo CE’s current line of L90 wheel loaders.