Search Results

The detailed analysis of the tire loading and the subsequent deformations under operational driving conditions is of great importance for the basic investigation of the functionability as well as for the input and verification of the computer simulation of tires. Such data are also required for the definition of mission profiles as well as for the derivation of programs for the durability approval. The principles for the measurement of global tire deformations by spring loaded deflection transducers arranged in-between the tire crown and the rim are described. By combination of those sensors with wheel force transducers the determined tire deformations are referred to the actual service loading conditions. The sensors and transducers are described and examples of field measurement on heavy truck tires under distinguished driving conditions are presented.

Experience from several car projects shows that S-N curves for spot welds generated under load control in the high cycle fatigue regime might be very conservative when used in the low cycle fatigue regime. Therefore, force and displacement controlled low cycle fatigue tests were carried out on peel and shear loaded specimens. Both constant (CA) and variable amplitude (VA) load signals were used. Finally, a method for predicting fatigue life of spot welds with increased accuracy in the low cycle fatigue regime is proposed. The method is simple, fast and accurate and can be used together with linear finite element analysis (FEA) and existing fatigue packages.

The design and validation process of a new car requires detailed knowledge of the interaction of dynamic forces and moments introduced into the rotating wheel. These forces are measured under operating conditions with appropriate sensors and transducers. Due to the effects of the dynamic masses, the loads should be sensed as close to the tire/road interface as possible using a wheel load transducer. Currently, existing transducers are quite heavy, not very accurate and elaborate calibrations and computations have to be performed. With the newly developed VEhicle LOad Sensor (VELOS), these deficiencies are overcome. Examples of dynamic force and moment calibrations with the original tire are presented, as well as road load data acquisitions comparing results from the VELOS with those of the axle transducers on a passenger car under different driving maneuvers.