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Body Structure Strength Of Sleeper Coaches During Rollover Test As Per AIS 119

International Centre For Automotive Tech.-Gopal Singh Rathore
  • Technical Paper
  • 2019-28-2567
To be published on 2019-11-21 by SAE International in United States
Bus passenger safety has always been a concern considering various impacts like side impact, front impact, rollover etc. happening in real life scenarios. Various standards have been formulated for simulating these conditions and with respect to rollover, standards like ECE-R66 are being used to understand the superstructure strength. In India, we have AIS-052 (bus body code) and AIS-031 specific for bus rollover testing. AIS-119 has been published for rollover testing of sleeper coaches with modifications in the survival space creation in sleeper coaches for berths. With physical testing being more expensive, CAE simulations are being considered as vital option which also helps in design modification in a lesser time. This paper discusses the scope of numerical simulation of sleeper coach rollover using an explicit dynamic solver RADIOSS to understand the structure deformations, survival space clearances/intrusions. The paper will describe the procedure for the numerical simulation starting from the CAD development, geometry clean up, meshing techniques, element formulations, CG measurement, input deck set up till the post processing of results. In order to validate the numerical…
 

Passenger "Sleeper Bus" Structure, an Optimization Study using Finite Element Analysis

JCBL, Ltd.-Yaseen Khan
JCBL,Ltd.-Priyanka Bhola
  • Technical Paper
  • 2019-28-2537
To be published on 2019-11-21 by SAE International in United States
ABSTRACT Sleeper buses are increasingly used as connectivity between cities and remote areas with sleeping comfort for passengers. During the normal operation, the bus body is subjected to several loads, external loads from the road (i.e. crossing over a speed bump, breaking & cornering). Moreover, there is a substantial possibility that these loads may lead to a structural failure. Hence, it is necessary to determine stresses occurred in the bus body to ensure its integrity under these driving scenarios. During the accident, rollover/front/rear/side impact, energy absorbing capacity of bus body structure is crucial for safety of passengers. The objective of this study is to reduce weight of bus structure while maintaining cost & safety as constraint. 3D Model prepared in NX and finite element model created in hypermesh ,LS-dyna/optistruct used as solver and post processing done in hyperview. In this study, fully loaded bus with passengers as well as maximum language mass, considered. The present study is based on the finite element analysis and design optimization of passenger sleeper bus. Number of iterations in stiffness…
 

New Half Shaft Bench Test Methodology for NVH Characterization

FCA US LLC-Wei Yuan, Ahmad Abbas, Francisco Antonio Sturla
Siemens PLM Software-Saeed Siavoshani, Prasad Balkrishna Vesikar
Published 2019-06-05 by SAE International in United States
The main purpose of this paper is to develop a reliable bench test to understand the vibratory behavior of the half shafts under applied torque comparable to an idle condition. In some cases, the half shaft path is a major factor influencing the idle vibration in the vehicle. At idle condition vehicle vibrations are caused by engine excitation and then they pass through different paths to the body structure. Half shaft manufacturers generally characterize shaft joints for their frictional behavior and typically there is no data for vibration characteristics of the half shaft under idle conditions. However, for predictive risk management, the vibratory behavior of the half shaft needs to be identified. This can be achieved from measured frequency response functions under preloaded test conditions.This bench test enables manufacturers to conduct comprehensive design of experiments on the impact of powertrain vibration input while transmitting through the half shaft into the vehicle system. This method enables the study of the half shaft at the component level, because studying the half shaft at vehicle level is difficult…
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Comparison between Finite Element and Hybrid Finite Element Results to Test Data for the Vibration of a Production Car Body

Michigan Engineering Services, LLC-Geng Zhang
University of Michigan-Nickolas Vlahopoulos, Sungmin Lee
Published 2019-06-05 by SAE International in United States
The Hybrid Finite Element Analysis (HFEA) method is based on combining conventional Finite Element Analysis (FEA) with analytical solutions and energy methods for mid-frequency computations. The method is appropriate for computing the vibration of structures which are comprised by stiff load bearing components and flexible panels attached to them; and for considering structure-borne loadings with the excitations applied on the load bearing members. In such situations, the difficulty in using conventional FEA at higher frequencies originates from requiring a very large number of elements in order to capture the flexible wavelength of the panel members which are present in a structure. In the HFEA the conventional FEA model is modified by de-activating the bending behavior of the flexible panels in the FEA computations and introducing instead a large number of dynamic impedance elements for representing the omitted bending behavior of the panels. The excitation is considered to be applied on the conventional FEA model and the vibration analysis is conducted using the FEA. The power flow through the dynamic impedance elements is computed, and in…
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Rethinking aluminum for NVH abatement

Automotive Engineering: June 2019

Lindsay Brooke
  • Magazine Article
  • 19AUTP06_01
Published 2019-06-01 by SAE International in United States

Engineers, abandon those mastics! New “quiet” materials solutions are at hand.

Engineers who have witnessed aluminum-intensive vehicles being “uncloaked” in a full competitive teardown relate the same story: After you've pulled the carpet out and stripped it down to the naked bodyshell, the “band-aids” are clearly exposed-typically on the floorpan, bulkheads, on the rear package tray of sedans, around the wheelhouses, and within the noise-critical dash panel and cowl plenum.

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EDITORIAL: The unforgettable pyramid on the hood

Automotive Engineering: June 2019

Editor-in-Chief-Lindsay Brooke
  • Magazine Article
  • 19AUTP06_08
Published 2019-06-01 by SAE International in United States

If you're old enough to remember 1990, you may recall the best television ad of the year. It showed the front end of the all-new Lexus LS400 sedan against a black background. A multi-level pyramid of champagne glasses glistened in the center of the car's hood.

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The economics of materials selection

Automotive Engineering: May 2019

Lindsay Brooke
  • Magazine Article
  • 19AUTP05_02
Published 2019-05-01 by SAE International in United States

Cost per pound of reduced vehicle mass is helping to drive innovation in steel, aluminum and carbon composites.

“We've entered an era where true weight reductions in vehicles are occurring,” noted Dr. Alan Taub, professor of Material Science & Engineering at the University of Michigan. “There is no new vehicle launch that doesn't talk about a 5-10 percent reduction in curb weight because it's now clearly a part of fuel economy. And while the gains are still coming from powertrain improvements and the introduction of partial and full electrification, about 15 percent of fuel-economy improvements today come from vehicle weight reduction.” His rule of thumb: Decreasing vehicle weight by 10% yields a 6% improvement in fuel economy.

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Aluminum: Toward 50% body content

Automotive Engineering: May 2019

Lindsay Brooke
  • Magazine Article
  • 19AUTP05_04
Published 2019-05-01 by SAE International in United States

Aluminum BIW and closure parts are the key to achieving both regulatory and OEM goals for improved vehicle efficiency going forward.

To vehicle-development teams, peaceful coexistence is the 2020's way of describing the relationship between steel and aluminum. Sure, the two giant materials industries will continue their battle to conquest one another's market share. But for vehicle planners and program-development teams, the ferrous and light metals are an increasingly effective and popular combination. As experts Dr. Alan Taub and Michael Robinet have noted elsewhere in this issue, the mixed-materials trend is becoming an enduring one, as evidenced across the landscape of recent new-vehicle introductions.

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Steel stands TALL

Automotive Engineering: May 2019

Lindsay Brooke
  • Magazine Article
  • 19AUTP05_01
Published 2019-05-01 by SAE International in United States

Mobility's longtime incumbent material maintains its star status for vehicle structures through constant innovation-and a collaborative development model.

In 2014, just before Ford shook the industry with the introduction of its aluminum-intensive F-150, Ducker Worldwide released a study for the aluminum industry. The report predicted that the light metal would dominate the North American light-truck segment in the next new-model development cycle. Some seven out of ten pickups in the next round were going to be AL-intensive, the study opined. A tidal wave appeared to be building.

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Prediction of Ductile Fracture Propagation of High Strength Steels in Automotive Structures

Honda R&D Co., Ltd.-Hideyuki Okada, Yasuhisa Egawa, Kenichiro Fukagawa
JFE Steel Corporation-Kentaro Sato, Takayuki Futatsuka
Published 2019-04-02 by SAE International in United States
Initiation and propagation of ductile fractures in crashed automotive components made from high strength steels are investigated in order to understand the mechanism of fracture propagation. Fracture of these components is often prone to occur at the sheet edge in a strain concentration zone under crash deformation. The fracture then extends intricately to the inside of the structure under the influence of the local stress and strain field.In this study, a simple tensile test and a 3-point bending test of high strength steels with tensile strengths of 590 MPa and 1180 MPa are carried out. In the tensile test, a coupon having a hole and a notch is deformed in a uniaxial condition. The effect of the notch type on the strain concentration and fracture behavior are investigated by using a digital imaging strain measurement system. For the 3-point bending test, hat-shaped parts having various types of notches and a hole located near the notch are examined to simulate ductile fracture in a crashed automotive part. The experimental results indicate that the shape of the…
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