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This paper presents an experimental investigation of the effect of threaded fastener condition on the low cycle fatigue behavior of a tightened metric fastener under a fully reversed, cyclic transverse load. The test set-up subjects tightened, threaded fasteners to the combined effect of axial, torsional, bending, and transverse shear loading. The two conditions of the fasteners were “as received” and “ultrasonically cleaned and oiled”. Fatigue performance at three different bolt tension levels was investigated. Based on preliminary testing arbitrarily selected amplitude of 0.05 inches was used for the cyclic transverse displacement, at a frequency of 10 Hz. A Scanning Electron Microscope (SEM) was used to assess the failure mode on a bolt fracture surface. The bolt stresses are sensitive to both thread and under head friction characteristics.

The statistical trends of the spindle loads extracted from road load test data of vehicles with different variants are presented in this paper. The road load data of a vehicle moving on the same track with single speed are considered with different variants of the vehicle. The variants considered are repeat runs, spindle loads in vehicles with different ballast conditions, difference in type of leaf spring shackles and changed number of frame to body mounts. The parameters considered for the statistical trend comparison are the spindle forces, spindle moments and spindle accelerations monitored in different directions. The data analysis was performed using the software functions in N-soft and MATLAB. The analyzed results were grouped and bar charts are prepared to bring out the statistical variations of different parameters.

Dynamic interactions of urban buses with urban roads are investigated in view of the vibration environment for the driver and dynamic tire forces transmitted to the roads. The static and dynamic properties of suspension component and tires are characterized in the laboratory over a wide range of operating conditions. The measured data is used to derive nonlinear models of the suspension component, and a tire model as a function of the normal load and inflation pressure. The component models are integrated to study the vertical and roll dynamics of front and rear axles of the conventional and modern low floor designs of urban buses. The resulting nonlinear vehicle models are thoroughly validated using the fieldmeasured data on the ride vibration and tire force response of the buses.