Search Results

The scope of the project is to achieve SUV structural performance improvement to meet the offset frontal crash safety requirements as per ECE R 94 Regulation by design modifications in different Sub-systems of the vehicle structure suggested with the help of CAE crash simulations. The study can be classified in four main phases mentioned below. The first phase of the development is to conduct a crash test and CAE simulation for the baseline design. The second phase includes correlation activity among baseline test and CAE. The third phase is to achieve improvement by vehicle structure design modifications and new parts in chassis and BIW guided with CAE simulations and design iterations. Finally the forth phase deals with validation of new crashworthy vehicle design by last crash test.

Virtual assessment of an occupant postural ergonomics has become an essential part of vehicle development process. To design vehicle for different market is one of the primary reason for manufacturers using digital tools to address the specific needs of the target market including cultural background, road and traffic conditions. RAMSIS is a widely used software for creating digital human models (DHM) of different target population which allows manufacturers to assess design with unique customer requirements in product design. Defining these requirements with RAMSIS human module helped development team to accurately define occupant targets such as occupant space, visibility and reachability etc. Occupant behavior and usage scenario are factors which are unique to target market and they influence the occupant posture and usage pattern inside the vehicle. This paper defines the methodology towards the development of Indian Digital Simulation model for vehicle ergonomic evaluations.

Traffic awareness of the driver is one of the prime focus in terms of pedestrian and road safety. Driver experience plays a significant role and driving requires careful attention to changing environments both within and outside the vehicle. Any lapse in driver attention from the primary task of driving could potentially lead to an accident. It is observed that, lack of attention on the ongoing traffic and ignorant about the traffic information such as traffic lights, road signs, traffic rules and regulations are major cause for the vehicle crash. Traffic signals & signage are the most appropriate choice of traffic control for the intersection, it is important to ensure that driver can see the information far away from the intersection so that he/she can stop safely upon viewing the yellow and red display. Then, upon viewing the signal operations and conditions the motorist can stop his/her vehicle successfully before entering the intersection.

The development of interior fittings of passenger car to minimize the injuries to the head of the occupants requires mandatory compliance to the regulations in Europe and USA. In European regulation ECE R21 and similarly in FMVSS 201 the test on the instrument panel area suffices. The FMVSS 201u requirements in USA require also a free motion headform to be impacted on additional areas of the A-Pillar trim, sun visors, grab handles, and seat belt upper anchorage points of the B-Pillar too. Free Motion Headform Impactors (FMHI) are costly equipment. The FMVSS 201u [1] test is not conducted by any test agency in India as yet. Paper deals with the development of the head form impactor to fire the headform at angular positions in the vehicle and the test results have enabled the development of the vehicle interiors to enhance the safety of vehicles in crash situations.

In the new product design, meeting customer requirements, process alignment, timely execution and successful implementation plays a critical role. Six sigma methodology is a disciplined, standardized methodology supported by analytical tools to meet the quality and functional targets. An engine cradle or sub-frame is the principal load carrying member in a monocoque vehicle construction. It is extensively used to (i) provide structural support and retention of power train, suspension control arms, stabilizer bar, and steering rack mounting features (ii) to isolate the high frequency vibrations of engine and suspension from the remaining structures (iii) to absorb and transmit the impact forces during frontal crash. This paper attempts to explain (i) the various DFSS-DMADV techniques used during the engine cradle design and development (ii) correlation between the cradle stiffness simulation and test measurement values (iii) cradle NVH test results.

Airbags play a vital role in occupant protection during a crash event. Apart from the crash test the airbags have to additionally meet the requirements of the ECE R 12 headform impact test with Driver's Airbag (DAB) located in the steering wheel being deployed and the ECE R21 headform impact test for Passenger Airbag (PAB) in undeployed condition. Improper location of the PAB module below the Instrument Panel, the design of the air bag housing and the Instrument Panel are some of the factors that could lead to non compliance of the components of the uninflated PAB. The paper deals with the investigation conducted for compliance of the PAB to ECE R 21 with the uninflated air bag in meeting the requirements of 80 g at 19.3 km/h by proper location, changes to the design of the PAB cover, air bag housing brackets, etc.

Validation of vehicle structure is at the core of reduction of product development time. Robust and accelerated validation becomes an important task. In service the vehicle is subjected to variable loads. These act upon the components that originate from road roughness, manoeuvres and powertrain loads. Majority of the body in white and chassis structural failures are caused due to vertical loading. Measured road load data in test track have variable amplitude histories. These histories often contain a large percentage of small amplitude cycles which are non damaging. This paper describes a systematic approach to derive the compressed load cycle from the measured road load data in order to produce representative and meaningful yet economical load cycle for fatigue simulation. In-house flow was developed to derive the compressed load time history.

In current competitive environment automobile industry is under heavy pressure to reduce time to market. First time right design is an important aspect to achieve the time and cost targets. CAE is a tool which helps designer to come up with first time right design. This also calls for high degree of confidence in CAE simulation results which can only be achieved by undertaking correlation exercises. In automobiles most of the structures are subjected to vibration from dynamic loads. All the dynamic road loads are random in nature and can be very easily expressed in terms of power spectral density functions. In the current scenario structural durability of the parts subjected to vibration is done partially through modal performance and partially though frequency response analysis. The only question that arises is what amplitude to use at what frequency and how to map all the accelerated tests dynamic load frequency spectrum to simulation domain.

Regulations on pedestrian safety have been introduced globally since the year 1990 and in India it will have to be met around the year 2016. Process of making vehicle compliant to this regulation requires rigorous design development and testing. Testing involves propelling head-forms (Child and Adult) on bonnet at 35 km/h and 40 km/h and leg-forms (Upper and Lower) on bumper at 40 km/h according to the different National / International / NCAP regulatory requirements A pedestrian protection test rig has been indigenously designed and developed in-house to perform pedestrian protection impact testing in-house. The paper describes the salient features of the pedestrian protection test rig, its functioning, operation and process of acquiring the data for determination of the values required by crash safety regulations.

Drive cycles have been an integral part of emission tests and virtual simulations for decades. A drive cycle is a representation of running behavior of a typical vehicle, involving the drive pattern, road characteristics and traffic characteristics. Drive cycles are typically used to assess vehicle performance parameters, perform system sizing and perform accelerated testing on a test bed or a virtual test environment, hence reducing the expenses on road tests. This study is an attempt to design a relatively robust process to generate a real world drive cycle. It is based on a Six Sigma design approach which utilizes data acquired from real world road trials. It explicitly describes the process of generating a drive cycle which closely represents the real world road drive scenario. The study also focuses on validation of the process by simulation and statistical analysis.

A cabin on an agricultural tractor is meant to protect the operator from harsh environment, dust and provide an air conditioned space. As it is an enclosed space, cabin structure should be a crashworthiness structure and should not cause serious injury to operator in case of tractor roll over. There are International standard like OECD Code 4, SAE J2194 which regulates the crashworthiness of this protective structure. The roll-over protective structure (ROPS) is characterized by the provision of space for a clearance zone large enough to protect the operator in case of tractor overturn. None of the cabin parts should enter into the clearance zone for operator safety. In addition to meeting ROPS test criteria, the cabin structural strength should be optimized for the required tractor life. In this paper, simulation process has been established to design an agricultural tractor cabin structure and its mountings to meet the above requirements.

Electric cars are the future of urban mobility which have very less carbon foot print. Unlike the conventional cars which uses BIW (Body in White), some of the electric cars are made with a space frame architecture, which is light weight and suitable for low volume production. In this architecture, underbody consists of frames, battery pack, electronics housing and electric motor. Underbody drag increases due to air entrapment around these components. Aerodynamic study for baseline model using CFD simulations showed that there was a considerable air resistance due to underbody components. To reduce the underbody drag, different add-ons are used and their effect on drag is studied. A front spoiler (air dam) is used to deflect the incoming air towards sides of the car. A under hood cover for front components, trailing arm cover for trailing arm and rear bumper cover for rear components were used to reduce underbody drag.

Ride is essentially the outcome of coupled dynamics of various involved sub-systems which make it too complex to deal analytically. Tires, amongst these, are known to be highly nonlinear compliant systems. Selection of tires specifications such as rated tyre pressure, etc. are generally decided through subjective assessment. While experts agree that tyre pressure affects the attributes such as ride to a noticeable degree, the quantification of the change often remains missing. In the current work, vibration levels of various sub-systems relevant to ride in an SUV are measured for three different tyre pressures at different speeds over the three randomly generated roads. For the purpose, artificial road profiles of classes A, B and C are synthesized from the spectrum of road classes defined in ISO 8608:2016 and reproduced on a four-poster test rig.

Roll-over protective structures (ROPS) are safety devices which provide a safe environment for the tractor operator during an accidental rollover. The ROPS must pass either a dynamic or static testing sequence or both in accordance with SAE J2194. These tests examine the performance of ROPS to withstand a sequence of loadings and to see if the clearance zone around the operator station remains intact in the event of an overturn. In order to shorten the time and reduce the cost of new product development, non-linear finite element (FE) analysis is practiced routinely in ROPS design and development. By correlating the simulation with the results obtained from testing a prototype validates the CAE model and its assumptions. The FE analysis follows SAE procedure J2194 for testing the performance of ROPS. The Abaqus version 6.12 finite element software is used in the analysis, which includes the geometric, contact and material nonlinear options.

Reducing material wherever there is a possibility in automobile industry is inevitable for weight and cost saving. This paper explains about the possibilities of optimizing the material composition of automotive Headliners (also called as Roof liners) without affecting the performance and safety criteria. In this paper, we are targeting at optimizing the individual constituents of a composite Headliner. A conventional Headliner comprises of many sandwich layers of which PU foam shares the major percentage of the composition contributing to 80% of the Headliner thickness. In this paper, we are discussing about the optimization done in Headliner sandwich constituents without affecting the core performance parameters of headliner such as curtain airbag deployment, ergonomic regulations, drop test etc. By incorporating this change, without significant changes in other layers, overall weight reduction of ~24% and overall cost reduction of ~24% is achieved.