Powertrain Cradle Verification and Validation for Bus Application Export Market 2018-01-1379
To capture market share in different regions of the world, the product must fit different road profiles and operating conditions. Designing a product which suits two different markets requires many factors to be considered like the topography, driving pattern and road load profiles. This project deals with once such situations and required a stringent validation protocol which shall encompass all possible driving scenarios. The fully built vehicle is to be exported to a different market and required powertrain change and subsequently required a new cradle design. Customer usage and road profile study was carried out in the new market to estimate the percent operation in each zone i.e. good road and bad road.
CAE analysis carried out to capture stress hotspots and possible failure locations. Vehicle is taken to road to measure frame acceleration at different speeds i.e. 40 kmph to 100 kmph. Considering the vehicle operating condition and future requirements, it is decided to do multi-axis simulation test. Multi-axis rig can simulate vehicle parameters like vertical, braking, pitch, and roll etc. A sturdy and modular fixture made to accommodate cradle and its components as in vehicle. Standard sections were chosen to make test setup as it can be used to make the setup stiffer, thus replicating the actual vehicle. The fixture setup resembled bus body structure and ensured no resonance by adding suitable stiffeners.
Constant spectral density and On-road data were taken and analysis is carried out to find out proper signal to simulate. Then it is decided to simulate CSD data since it produced greater damage compared to on-road signal. Pseudo damage comparison is used to figure out test duration required since it is an accelerated test. Strain gauges were also installed on CAE stress hotspots and values are recorded during simulation.