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Globally, automotive sector is moving towards improving off-road performance, durability and safety. Need of off-road performance leads to unpredictable overload to powertrain system due to unpaved roads and abuse driving conditions. Generally, shafts and gears in the transmission system are designed to meet infinite life. But, under abuse condition, it undergo overloads in both torsional and bending modes and finally, weak part in the entire system tend to fail first. This paper represents the failure analysis of one such an incident happened in output shaft under abuse test condition. Failure mode was confirmed as torsional overload using Stereo microscope and SEM. Application stress and shear strength of the shaft was calculated and found overstressing was the cause of failure. To avoid recurrence of breakage, improvement options were identified and subjected to static torsional test to quantify the improvement level.

There is a higher demand for quieter tractors in the agri-industry, as the continued exposure to noise levels have disastrous effects on operator’s health. To meet the world-wide regulatory norms and to be the global market leader, its mandatory to develop the comfortable tractor which meets homologation requirements and customer expectations. Typically, Operator Ear Level (OEL) noise has been evaluated in the test, after First Proto has been made. This approach increases cost associated with product development due to late changes of modifications and testing trails causing delay in time-to-market aspect. Hence, there is a need to develop the methodology for Predicting tractor OEL noise in virtual environment and propose changes at early stage of product development. At first, full vehicle comprising of skid, sheet metals and Intake-exhaust systems modelled has been built using Finite Element (FE) Preprocessor.

Body-over-Frame is the primary type of construction used in SUVs, pick-ups, and other commercial vehicles in India. In this type of construction, the body, engine, suspensions etc. are mounted on the ladder frame. Since the frame acts as the skeleton of the vehicle, optimal design of frame at the concept stage of the vehicle program is critical for meeting all structural performance targets. Frontloading of these targets aids in architecture development and reduces future design modifications. The natural frequency response from the frame directly affects the NVH performance of the vehicle. This paper focuses on frontloading the natural frequency targets by performing concept-level simulations on the ladder frame even before creation of 3D concept data. A parametric beam model is created based on the reference vehicles. The beam model has been validated with correlation of more than 85% compared with CAE and physical testing outputs of existing vehicles.

Engine radiated noise has complex behavior as engine assembly consist different components, varying dynamic forces with wide range of speed. For open station tractor, engine noise is major contributor and hence needs to be optimized for regulatory norms as well customer comfort. The awareness about NVH comfort in domestic market as well as export market is increasing as customer have become more demanding. This forces OEM’s to put serious efforts to ensure the OEL noise / Engine noise is at acceptable levels. Identifying the optimized countermeasures to reduce the engine noise during the early design phase has a greater impact in reducing product development time and cost. This paper describes about a process that has been established for evaluating engine radiated noise and to improve the overall NVH performance.

Rear axles are subjected to bending and torsion loads out of which Bending loads are predominant. In case of Off road vehicles Bi Axial- combination of Bending and torsion loads were predominant, because of axle construction and vehicle usage pattern. Defined test procedures are available for bending durability and torsional durability evaluation of axles. In this experiment, new test methodology was developed for Bi Axial durability evaluation of Off road vehicle rear axle with single servo hydraulic linear actuator. For creating Bi Axial load condition, we may need multiple actuators and complicated fixtures. Axle wheel end is constrained at an angle with suitable fixtures for creating the bending and torsional forces together in the axle. Servo hydraulic linear actuator with suitable loading arm is used for applying the test torque in the axle input flange.

Validation of vehicle structure by use of finite element analysis is at the core of reduction of product development time. In the early phase of validation it is required to evaluate the strength of the vehicle structure to account for the loading during physical validation and service loading. In service the vehicle is subjected to variable loads. These act upon the components that originate from road roughness, maneuvers and power train loads. All systems in the vehicle represent more or less complicated elastic structures subjected to time varying loads. A time domain dynamic assessment of the vehicle structure is time consuming and expensive. Also in the early phase of design wherein several design iterations need to be carried out for design validation, it is practically impossible to conduct a dynamic analysis and fatigue life assessment. Extreme static load cases are traditionally being used for this process.

The emerging business imperative of frequent new product introduction in market throws up challenge to shorten testing and evaluation time. Advanced test facilities and statistical tools have a greater role in reducing the evaluation cycle time. Considering limitations of field testing, a need was felt to simulate field condition in the laboratory i.e., ‘Bringing field to lab’. In this paper, an effort is made to explain the concept of ‘Bringing field to lab’ and the approach towards accomplishing it. The methodology developed for assessing effectiveness of laboratory tests i.e., ‘Power of Lab’ is shared. Various means of accelerating the tests and verifying field to lab correlation are explained. In quest to pursue the vision of ‘Bringing field to lab’ program, a new test facility has been developed to evaluate tractor i.e., Three-Poster Test System. Features of this test system, along with it’s role in ‘Bringing field to lab’, are shared along with the test results obtained.