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Suspension hard points optimisation

Altair Engineering-AshithKumar Shetty
  • Technical Paper
  • 2019-28-2419
To be published on 2019-11-21 by SAE International in United States
Objective This paper explores the usage of Altair simulation driven optimisation process, Front Suspension hard points of a sedan Car model are optimised for specific target toe curves using MotionView, MotionSolve and HyperStudy This process gives the optimal hard point values to match the target curves without much iterations. Methodology Parametric Multibody model of the front end of sedan is built in MotionView. To Carry out optimisation HyperStudy is used where few of the suspension hard points which affect the toe curves are chosen as design variable. For the chosen Design variables upper and lower bound limits are specified. Ride, Roll and lateral force tests are performed. Optimisation is performed using HyperStudy where it iterates the suspension hard points to match the target toe curves. Each iteration response can be visualized in HyperStudy and can be compared with the target toe curve. Hyperstudy points the iteration which is closest to the Target curve Advantage • Quick model setup and run time • Parametric model allows quick change in design • Insight at early design stage…
 

Transient Response Analysis and Synthesis of an FSAE Vehicle using Cornering Compliance

SRM Institute Of Science And Technology-Vasanthkumar CH, Shubham Subhnil, Pranav Suresh, K Kamalakkannan
SRM Institute of Science & Technology-Nanthakumar Ajd
  • Technical Paper
  • 2019-28-2400
To be published on 2019-11-21 by SAE International in United States
OBJECTIVE Race vehicles are designed to achieve higher lateral acceleration arising at cornering conditions. A focused study on the steady state handling of the car is essential for the analysis of such conditions. The transient response analysis of the car is also equally important to achieve best driver-car relationship and to quantify handling in the range suitable for a racing car. This research aims to investigate the design parameters responsible for the transient characteristics and optimize those design parameters. This research work examines the time-based analysis of the problem to truly capture the non-linear dynamics. Apart from tires, chassis can be tuned to optimize vehicle handling and hence the response times. METHODOLOGY To start with, the system is modelled with governing parameters and simulation is carried out to set baseline configurations. Steady state and transient handling simulations run independent of each other with independent logic, coded on MATLAB. The static testing of the chassis is carried over using a Kinematic & Compliance (K & C) testing rig to get Compliance Budget and hence the calculated…
 

Evaluating the Effect of Light Weighting Through Roll Stiffness Change on Vehicle Maneuverability and Stability

Maruti Suzuki India Ltd-Eric Pranesh Reuben, Sreeraj N
Maruti Suzuki India Ltd.-Raghav Budhiraja
  • Technical Paper
  • 2019-28-2406
To be published on 2019-11-21 by SAE International in United States
Objective To achieve better fuel economy and reduced carbon footprint, OEMs are reducing the sprung and unsprung mass. This translates into a reduction in stiffness which profoundly deteriorates the handling/road holding characteristics of the vehicle. To model these changes in stiffness, modifications are made to suspension roll stiffness at the front and rear. This study compares different configurations of roll stiffness and evaluates vehicle behavior using frequency response characteristics and phase change of Yaw Gain recorded. The present work associates acquired data with subjective feedback to outline the shift in vehicle balance emerging from a variation of sprung and unsprung mass ratio. Methodology To study the frequency response characteristics of the vehicle, the pulse input is chosen for this. An ideal pulse input’s Fourier transform represents constant amplitude over all the frequency ranges. By giving a single input, the system is subjected to a range of frequencies. The changes in roll stiffness at the front and rear axles are achieved through addition of Stabilizer Bars of different diameters and stiffness. The test is conducted using…
 

Correlation of Objective and Subjective test results for Ride comfort with Heave, Pitch and Roll motion for a Passenger Vehicle

Advanced Structures India-Anuj Jha, Rahul Ramola
Vellore Institute of Technology-Aniruddha Deouskar
  • Technical Paper
  • 2019-28-2410
To be published on 2019-11-21 by SAE International in United States
Research Objective The importance of evaluating ride comfort with high degrees of accuracy objectively and its correlation with subjective perception is increasing day by day because of the long duration of the driving experience. The complex motion of the vehicle which is the combination of heave, roll and pitch motion is responsible for causing extreme uneasiness to the driver as well as the passenger. In this paper, ride comfort evaluation is done on the highway with similar traffic conditions with the help of Vibration Dose Value Analysis, Suspension Working Space and Ride Diagram methods for two hatchbacks and its correlation with the complex motion like choppiness of the vehicle is established that will help us to enhance the driver ride experience. Methodology The ride testing is performed for two hatchbacks on a highway road with different kinds of terrain ranging from highly uneven road roughness to moderately smooth surface for a speed range of 60-100 kmph. The road environment is chosen for testing in order to record and analyze the most practical vehicle response to…
 
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Aluminum Alloy Bars, Rods, and Wire, Rolled or Cold Finished, 5.6Zn - 2.5Mg - 1.6Cu - 0.23Cr (7075-F), As Fabricated, or When Specified, Annealed (7075-O)

AMS D Nonferrous Alloys Committee
  • Aerospace Material Specification
  • AMS4186E
  • Current
Published 2019-08-01 by SAE International in United States

This specification covers an aluminum alloy in the form of bars, rods, and wire, in the sizes shown in 3.3.3, in the “as fabricated (F) temper” (see 8.5). When specified, product shall be supplied in the annealed (O) condition.

 
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Aluminum Alloy Bars, Rods, and Wire Rolled or Cold Finished, and Rings, 5.6Zn - 2.5Mg - 1.6Cu - 0.23Cr (7075-T6, 7075-T651), Solution and Precipitation Heat Treated

AMS D Nonferrous Alloys Committee
  • Aerospace Material Specification
  • AMS4122M
  • Current
Published 2019-08-01 by SAE International in United States

This specification covers an aluminum alloy in the form of rolled or cold finished bars, rods, and wire, and of flash welded rings conforming to the dimensions listed in Table 2 (see 8.4).

 
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Aluminum Alloy, Rolled or Cold Finished, Bars and Rods, 12.2Si - 1.0Mg - 0.90Cu - 0.90Ni (4032-T651), Solution Heat Treated, Stress Relieved, Artificially Aged

AMS D Nonferrous Alloys Committee
  • Aerospace Material Specification
  • AMS4319C
  • Current
Published 2019-07-12 by SAE International in United States

This specification covers an aluminum alloy in the form of bars and rods 0.750 to 3.500 inches (19.05 to 88.90 mm), inclusive, in nominal diameter or least distance between parallel sides (see 8.5).

 

Speed Planning and Prompting System for Commercial Vehicle Based on Real-Time Calculation of Resistance

SAE International Journal of Commercial Vehicles

Wuhan University of Technology, China-Zhaocong Sun, Zhimin Li, Jinyi Xia, Gangfeng Tan
  • Journal Article
  • 02-12-03-0013
Published 2019-06-25 by SAE International in United States
When commercial vehicles drive in a mountainous area, the complex road condition and long slopes cause frequent acceleration and braking, which will use 25% more fuel. And the brake temperature rises rapidly due to continuous braking on the long-distance downslopes, which will make the brake drum fail with the brake temperature exceeding 308°C [1]. Meanwhile, the kinetic energy is wasted during the driving progress on the slopes when the vehicle rolls up and down. Our laboratory built a model that could calculate the distance from the top of the slope, where the driver could release the accelerator pedal. Thus, on the slope, the vehicle uses less fuel when it rolls up and less brakes when down. What we do in this article is use this model in a real vehicle and measure how well it works. Thus, to improve the safety and economy of commercial vehicles on mountainous areas, the Vehicle Speed Planning and Prompting System based on real-time calculation of resistance is established. The system consists of four parts: Hardware on Vehicle, Microcontroller Unit…
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Development of an Accelerated Test for Tire Flat-Spotting

NissanTechnical Center North America-Farokh Kavarana, Scott Fritz
Published 2019-06-05 by SAE International in United States
Tire flat-spotting occurs when tires remain in a loaded condition without rolling for an extended period of time, and can be temporary or permanent depending on the length of storage, vehicle loading and environmental factors. Tire non-uniformity caused from flat-spots often induce shake and shimmy vibration in vehicles due to increased tire-wheel force variation input into the chassis. This results in increased warranty costs for OEMs and tire suppliers and customer dis-satisfaction in third-party quality surveys such as J. D. Power IQS. Flat-spotting is of particular concern for slow-moving vehicle inventory parked for long periods at plants and/or dealership lots.OEMs often stipulate or recommend inventory storage practices for dealers that require physical movement of vehicles at some set duration to reduce the risk of tires developing permanent flat-spots. OEMs also provide component level flat-spotting requirements to tire manufacturers during sourcing and specification timing to secure their internal requirements and targets. The study in this paper initially determined real-world flat-spotting levels on an actual vehicle during the adverse summer months of Arizona. Tire uniformity measured on…
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New Method for Decoupling the Powertrain Roll Mode to Improve Idle Vibration

FCA US LLC-Syed F. Haider, Ahmad Abbas, Francisco Sturla
Published 2019-06-05 by SAE International in United States
Modern engines have high torque outputs and have low RPM due to increased demand for fuel efficiency. Vibrations caused by such engines have to be mitigated. Decoupling the roll mode from the remaining five rigid body modes results in a response which is predominantly about the torque roll axis (TRA) and helps reduce vibrations. Therefore, placing the mounts on the TRA early in the design phase is crucial. Best NVH performance can be obtained by optimizing the powertrain mount parameters viz; Position, Orientation and Stiffness. Many times, packaging restricts the mounts to be placed about the TRA resulting in degradation in NVH performance. Assuming that the line through the engine mount (Body side) centers is the desired TRA, we propose a novel method of shifting the TRA by adding mass modifying the powertrain inertia such that the new TRA is parallel to and on top to the desired TRA. This in turn will decouple the roll mode and reduce vibrations. This problem is formulated as an optimization problem. The numerical examples presented in this paper…
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