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Determination of Multi-Axial Deformations on Tires and Flexible Exhaust Joins in Service
Published June 29, 1995 by Associazione Tecnica Dell'Automobile in Italy
Event: Advanced Measurement Techniques and Sensory Systems for Automotive Applications: Accuracy and Reliability
Complex components like tires and flexible exhaust joints are subjected under customer usage conditions to large variations in magnitude and combination of multi-axial loading conditions and subsequent deformations. In order to evaluate the influence of the operational conditions on the functionability and the durability, the global multi-axial deformations need to be measured. The reliable determination of the complex deformation behavior of tires and flexible joints under service conditions is of great importance for the development of new tires and exhausts. The design and dimensioning, the verification of computer simulations as well as appropriate procedures for testing rely on such data. Analysis of occurring failure mechanisms and sources as well as the characterization of different design concepts are supported by the knowledge of the operational deformation conditions. Spring Loaded Deflection Transducers (SLDT) arranged in the different coordinate directions on the components can be applied to determine the multi-axial deformations. Inside of the tires such sensors were installed between the tread and the rim. The deflection of the tread in radial, lateral and circumferential direction as well as the rotation of the tire patch can be calculated from the signals in a cross-section of the tire when driving. On flexible exhaust joints of passenger cars and light trucks such deflection transducers were arranged between the two ends to measure the three- dimensional deformations and rotations of the joints under different operational driving conditions. In this presentation the sensor concept, its adaptation to different measuring problems and the usage is described. Examples of measured deformations of passenger car and truck tires under different driving maneuvers are presented and discussed. Also the measured multi-axial deformations on flexible joints of a passenger car and light truck are shown under different driving maneuvers being important for exhaust systems. Examples of analysis are presented for the investigation of failure mechanisms and for the verification of test programs.