Search Results

In the automotive industry the requirement for low emissions has led to the demand for lightweight vehicle structures. Light weighting can be achieved through different iterative approaches but is usually time consuming. Current paper highlights deployment of the multi-loadcase optimization approach for light weighting. This work involves developing a process for multiple loadcase optimization for automotive hood. The main goal is to minimize the weight of a hood assembly by meeting strength and stiffness targets. The design variables considered in this study are thickness of the panels. Design constraints were set for stress and stiffness based on DVP (Design Verification Plan) requirement. Optimization workflow is setup in mode-frontier with design objective of minimizing weight of hood.

Design of powertrain mounting bracket is always a challenge in achieving good NVH characteristics and durability with less weight. For this activity engine mount load is necessary to optimize the weight to meet durability and NVH targets. This paper introduces a new method to calculate engine mount loads from chassis accelerations. The method starts by measuring chassis acceleration near engine mount location, then reproducing the same chassis acceleration in Multi Axis Shaker Table (MAST), and finally extracting the load in engine mount using testing (using load cell). The MAST test actuator displacement input is imported into ADAMS and engine mount loads are extracted. The extracted loads are correlated with physical test results. The correlation includes load time history and peak-to-peak load range. It is recommended to implement this method in early vehicle design phases. Implementing engine mount bracket weight optimization is desirable in early design stages.

This paper presents a comprehensive model of a hydraulic power steering system for predicting the transient responses under various steering inputs. The hydraulic system model, which integrates together all fluid line elements and hydraulic components, is formulated using the MSC Easy5 software. A full vehicle model is developed in ADAMS/Car. Functional Mock up Interface (FMI), a tool independent standard is used for co-simulation of ADAMS and Easy5 Dynamic models. This paper describes a co-simulation methodology developed using FMI interface for full vehicle Simulations using hydraulic power steering. A virtual simulation scheme is developed to obtain the system transient responses and the results are compared with those measured from the tests. In general, the simulation results agree with those obtained from the tests under the same steering inputs and operating conditions.

Ride is an important attribute which must be accounted in the passenger segment vehicles. Excessive H point acceleration, Steering wheel acceleration, Pitch acceleration can reduce the comfort of the driver and the passengers during high frequency and low frequency rough road events. Excessive Understeer gradient, roll gradient, roll acceleration and Sprung mass lift could affect the Vehicle driver interaction during Steady state cornering, Braking and Step steer events. The concept architecture of the vehicle plays an important role in how comfort the vehicle will be. This paper discusses how to improve SUV ride performances by keeping handling performance attributes same or better than base vehicle. Multi Objective Optimization was carried out by keeping spring, bushing and damper characteristic as the design variables to avoid new system or component development time and cost.

Designing a vehicle chassis involves meeting numerous performance requirements related to various domains such as Durability, Crashworthiness and Noise-Vibration-Harshness (NVH) as well as reducing the overall weight of chassis. In conventional Computer Aided Engineering (CAE) process, experts from each domain work independently to improve the design based on their own domain knowledge which may result in sub-optimal or even non-acceptable designs for other domains. In addition, this may lead to increase in weight of chassis and also result in stretching the overall product development time and cost. Use of Multi-Disciplinary Optimization (MDO) approach to tackle these kind of problems is well documented in industry. However, how to effectively formulate an MDO study and how different MDO formulations affect results has not been touched upon in depth.

Body in White (BIW) is one of the major mass contributors in a full vehicle. Bending stiffness, torsional stiffness, durability, crashworthiness and modal characteristics are the basic performance parameters for which BIW is designed. Usually, to meet these parameters, a great deal of weight is added to BIW. Sensitivity analysis helps to identify the critical panels contributing to the performance while BIW optimization helps to reduce the overall mass of the BIW, without compromising on the basic performances. This paper highlights the optimization study carried out on the BIW of a Sports Utility Vehicle (SUV) for mass reduction. This optimization was carried out considering all the basic performance parameters. In the initial phase of BIW development, optimization helps to ensure minimum BIW weight rather than carrying out mass reduction post vehicle launch.

The cylinder block for the power train has always been a classic example of concurrent engineering in which disciplines like NVH, Durability, thermal management and lubrication system layout contribute interactively for concept design. Since the concept design is based on engineering judgment and is an estimated design, the design iterations for optimization are inevitable. This paper aims at outlining a systematic approach for design of crankcase for fatigue which would eliminate design iterations for durability. This allows a larger scope for design improvement at the concept stage as the design specifications are not matured at this stage. A process of stress optimization is adopted which gives accurate dimensional input to design. The approach is illustrated with a case study where an existing crankcase was optimized for fatigue and significant weight reduction was achieved.