Failure Analysis of TPU Gaskets used in Hydraulic Fluid Systems

In most mechanical systems where fluids and gases are utilized or conveyed, the use of sealing gaskets is critical to maintain a leak-free system and to eliminate any possible loss in pressure. If sealing performance is compromised, it can lead to failure of the mechanical system during service. There are multiple parameters that may compromise the performance of a sealing gasket. A systematic failure analysis approach is necessary to evaluate these parameters and help determine the root cause of a given seal failure.

In this presentation, the failure analysis of a Thermoplastic Polyurethane (TPU) gasket will be reviewed. This component is used to create a mechanical seal in hydraulic fluid connector systems. Leaking seals were noted in the field, resulting in loss of power in heavy-duty hydraulic systems. During this analysis, multiple subject and exemplar gaskets were obtained and examined. Numerous non-destructive and destructive tests were performed on the TPU gaskets. The data obtained from the tests was used to characterize the gasket material properties and sealing performance under service conditions. Based on data analysis, gaskets failure was determined to be limited to specific lots that were manufactured in a narrow timeframe. A change in formulation chemistry of the TPU gasket material was subsequently identified. This presentation will detail the failure analysis process and the tools and techniques used to analyze and determine the root cause of failure in these TPU gaskets.