This thesis provides experimental static and dynamic results for four pairs of seals, including a pair of smooth seals and three pairs of centrally grooved seals. The grooved seals have groove depth to clearance ratios (Dg/C) of 5, 10, and 15. The radial clearance of each test seal is 0.0891 mm. Test conditions include three shaft rotational speeds from 4000 to 10000 rpm, three inlet oil pressures from 24 to 70 bars, and seal dimensionless eccentricities from 0 (centered) to 0.7. For each pair of test seals, dynamic results include stiffness and damping coefficients; static results include stator position, attitude angles, and seal leakage. Stiffness, damping, and leakage are compared among the seal pairs with various groove depths. Results show that all rotordynamic coefficients consistently decrease with increasing seal groove depths, and seal leakage remains constant through varying groove depths. Additionally, a comparison is made between experimental results of all test seals and XLLubeGT. XLLubeGT is a computer model developed at Texas A&M University, which uses a Reynolds equation + energy equation model to predict dynamic performance of a grooved seal. It operates on the assumption that the groove is large enough to create separate lands within the seal, creating a zero or negligible pressure perturbation across the seal. A comparison with XLLubeGT shows that even the seal with the largest groove depth tested is not deep enough to agree with XLLubeGT predictions.

A presente dissertação deseja mostrar a utilização do estudo de confiabilidade como uma ferramenta de melhoria de projeto de um produto. Para atingir o objetivo estudou-se a melhoria de um retentor automotivo através do estudo de sua confiabilidade e utilizando técnicas de engenharia do valor. Com esse estudo pretende-se mostrar a relação dos dados de campo e ensaios funcionais utilizados. Através da análise dos dados de campo, foi selecionada uma característica funcional a ser melhorada no produto. A técnica de engenharia do valor aplicada ao produto resultou na variável que deveria ser melhorada no produto, e a análise de confiabilidade antes e após a alteração no produto, juntamente com os ensaios funcionais acelerados mostram a eficácia da melhoria realizada no produto. / This research aims to show a way to use the reliability study as a tool to guarantee the improvements in a product design. To reach the goal, a improvement in a oil seal was executed through the study of its reliability and using the value engineer technique. This study aims to show the relationship between the field information and functional tests. Through the analysis of field information, the functional characteristic that must be improved in the product was selected, and the value engineering technique application result in an element that must be improved in a product. The reliability study after and before the change in product, together with functional tests showed the efficiency of the change in the product aimingat improving its operational life.

A presente dissertação deseja mostrar a utilização do estudo de confiabilidade como uma ferramenta de melhoria de projeto de um produto. Para atingir o objetivo estudou-se a melhoria de um retentor automotivo através do estudo de sua confiabilidade e utilizando técnicas de engenharia do valor. Com esse estudo pretende-se mostrar a relação dos dados de campo e ensaios funcionais utilizados. Através da análise dos dados de campo, foi selecionada uma característica funcional a ser melhorada no produto. A técnica de engenharia do valor aplicada ao produto resultou na variável que deveria ser melhorada no produto, e a análise de confiabilidade antes e após a alteração no produto, juntamente com os ensaios funcionais acelerados mostram a eficácia da melhoria realizada no produto. / This research aims to show a way to use the reliability study as a tool to guarantee the improvements in a product design. To reach the goal, a improvement in a oil seal was executed through the study of its reliability and using the value engineer technique. This study aims to show the relationship between the field information and functional tests. Through the analysis of field information, the functional characteristic that must be improved in the product was selected, and the value engineering technique application result in an element that must be improved in a product. The reliability study after and before the change in product, together with functional tests showed the efficiency of the change in the product aimingat improving its operational life.