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Fatigue life Prediction of HVAC pipe assembly for measured powertrain load by virtual simulation

FCA Engineering India Pvt., Ltd.-Sathish Kumar Pandi, C Elango, Kameswara Rao Appana, Roshan N. Mahadule, DivaKaruni Murali Krishna
  • Technical Paper
  • 2020-01-0188
To be published on 2020-04-14 by SAE International in United States
Structural durability of automotive components is one of the key requirements in design and development of today’s automobiles. Virtual simulations are used to estimate component durability to save the cost and time required to build the components and testing. The objective of this work is to find the service life of automotive HVAC pipe assembly by calculating cumulative fatigue life for operation under actual powertrain load conditions. Modal transient response analysis is performed using MSC-Nastran with the measured powertrain load time history. Strain based fatigue life analysis is carried out in n-code using modal superposition method (MSM). The estimated fatigue life was compared with the physical test results. This paper also explains the root cause of low fatigue life on pipe assembly and provide the solution. Keywords: Durability, HVAC Pipe, Powertrain, Modal Transient, Fatigue Life
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Improved PSD Fatigue Approach for large FE models with wide frequency range

Faurecia-Huai-Ren Shih
  • Technical Paper
  • 2020-01-0499
To be published on 2020-04-14 by SAE International in United States
Fatigue damage calculation are traditionally based on the time domain approach. Acceleration time history inputs are used to excite the system and the outputs are in a form of stress time history. This transient dynamic approach, as time history is intuitive to understand, provides straightforward and reasonable result. Nevertheless, a typical automotive proving ground test consists of 20 to 30 road events, it is not only computationally intensive but could be also a grueling process for engineer to carry out as it requires iteration for each event in the schedule before fatigue calculation. Alternatively, a frequency domain fatigue calculation is widely used. In this approach, both the dynamic loading and response are expressed in terms of Power Spectral Density (PSD) functions and the dynamic structure is treated as a linear transfer function. The transfer function is then multiplied with event PSD to get the PSD of the stress. This PSD approach can simplify the problem considerably as it requires simulation to be run only once. However, the approach itself still has some issues when it…
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On Road Fuel Economy Impact by the Aerodynamic Specifications under the Natural Wind

Honda R&D Co., Ltd.-Yasuyuki Onishi, Kenta Ogawa, Jun Sawada, Youji Suwa, Fortunato Nucera
  • Technical Paper
  • 2020-01-0678
To be published on 2020-04-14 by SAE International in United States
According to some papers, the label fuel economy and the actual fuel economy experienced by the customers may exhibit a gap. One of the reasons may stem from the aerodynamic drag variations due to the natural wind. The fuel consumptions are measured on the bench test under the several driving modes by using the road load as input conditions. The road load is measured through the coast down test under less wind ambient conditions as determined by each regulation. The present paper aims to analyze the natural wind specifications encountered by the vehicle on the public road and to operate a comparison between the fuel consumptions and the driving energy. In this paper, the driving energy is calculated by the aerodynamic drag from the natural wind specifications and driving conditions. This driving energy and the fuel consumptions show good correlation. The fuel consumption is obtained from the vehicle ECU data. The driving energy is calculated by the aerodynamic drag and the vehicle driving conditions through the time history data on the road. Aerodynamic drag is…
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Crack Initiation and Propagation Simulations for ManTen and RQC100 Steel Keyhole Notched Specimens Tested by the Fatigue Design & Evaluation Committee of SAE

University of Waterloo-F.A. Conle
  • Technical Paper
  • 2020-01-0191
To be published on 2020-04-14 by SAE International in United States
In the 1970s the Fatigue Design and Evaluation Committee of SAE tested 57 "Keyhole" notched specimens with three different variable amplitude(VA) histories using two materials; a lower strength ManTen steel and a higher strength boron steel RQC-100. Recordings were made of not only initiation and final fracture cycles but also a record of the advance of the cracks during the propagation phase. In this work the initiation fatigue life is predicted using the usual method of plasticity correction at the notch followed by a Palmgren-Miner summation of damage with mean stress correction. The emphasis of the study is on simulating the crack propagation results. For that phase the ASME da/dN vs. DeltaK lines augmented by Hasegawa et al's lines and thresholds for negative R ratios, were used specifically to help predict the propagation for one of the VA histories that had a significant negative mean. The open source crack propagation simulation program applied a material memory model to determine the crack advance on a reversal by reversal basis. The resulting crack advance plots are compared…
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Helicopter Transmissions, A Brief Overview of

Boeing Co.-Patrick R. Darmstadt, Mark Robuck
  • Technical Paper
  • 2020-01-0437
To be published on 2020-04-14 by SAE International in United States
Transmission and drivelines as they apply to helicopters are discussed including history, common configurations, and typical, industry design philosophies. A brief history of transmission used in helicopter applications is provided, including an emphasis on the flight critical nature of transmissions and drivelines in helicopter applications and how the helicopter transmission has evolved over their 100 years of service. Common helicopter drivelines are discussed for a variety of helicopter configurations (single main rotor, tandem rotor, and tilt rotor, among others), touching on typical shaft speed and horsepower ranges. Finally, typical helicopter transmission design practices are discussed for gear, bearing, and lubrication systems.
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An Analytical Approach for Calculating Instantaneous Multilayer-Coated Wall Surface Temperature in an Engine

University of Wisconsin Madison-G. Koutsakis, J.B. Ghandhi
  • Technical Paper
  • 2020-01-0160
To be published on 2020-04-14 by SAE International in United States
Thermal swing coatings that have low volumetric heat capacity and low thermal conductivity are attractive because they have the potential to significantly reduce heat transfer to the combustion chamber walls. This paper presents an analytical method for determining the exact solution of the time-resolved wall temperature during the engine cycle for any number of coating layers and properties using the Laplace transformed heat diffusion equation. The method relies only on material properties and the past heat flux history, and represents the exact solution of the heat diffusion equation. The analytical nature of the solution enables fast computation and, therefore, application to system-level optimization calculations. The model relies on an assumption of one-dimensional heat flow, and constant material properties. The major advantage of this approach compared to the standard finite difference approach, wherein the wall is finely discretized, is that there is no approximation and the accuracy is guaranteed, i.e., it does not depend on nodal density. Results are presented for both a quasi-steady operating condition and for an engine transient event. In the latter case…
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Akasol packs industry-leading energy density into new battery design

SAE Truck & Off-Highway Engineering: December 2019

Bill Visnic
  • Magazine Article
  • 19TOFHP12_08
Published 2019-12-01 by SAE International in United States

Projecting the market for full-electric and hybrid-electric commercial vehicles will continue to expand, Germany-based lithium-ion battery specialist Akasol recently announced production-readiness of a newly-developed battery pack that sets an energy-density benchmark. The company's president also confirmed Akasol will build a manufacturing facility in the Detroit area targeted to begin production in mid-2020.

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Self-Expressive & Self-Healing Closures Hardwares for Autonomous & Shared Mobility

General Motors Technical Center India-Vijayasarathy Subramanian, Biju Kumar, Masani Sivakrishna, Anandakumar Marappan
  • Technical Paper
  • 2019-28-2525
Published 2019-11-21 by SAE International in United States
Shared Mobility is changing mobility trends of Automotive Industry and its one of the Disruptions. The current vehicle customer usage and life of components are designed majorly for personal vehicle and with factors that comprehend usage of shared vehicles. The usage pattern for customer differ between personal vehicle, shared vehicle & Taxi. In the era of Autonomous and Shared mobility systems, the customer usage and expectation of vehicle condition on each & every ride of vehicle will be a vehicle in good condition on each ride. The vehicle needs systems that will guide or fix the issues on its own, to improve customer satisfaction. We also need a transformation in customer behavior pattern to use shared mobility vehicle as their personal vehicle to improve the life of vehicle hardwares & reduce warranty cost. We will be focusing on Vehicle Closure hardware & mechanisms as that will be the first and major interaction point for customers in vehicle. This gives us an opportunity to improve product life and customer experience in ride share and shared mobility…
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Methodology for Failure Simulation Using 4 Corner 6 DOF Road Load Simulator of Overhanging Components: An Experimental Approach

Maruti Suzuki India, Ltd.-Naveen Malik, Ayan Bhattacharya, Sahil Jindal, Sayed Zergham Ali Naqvi
  • Technical Paper
  • 2019-28-2404
Published 2019-11-21 by SAE International in United States
Nowadays, Road Load Simulators are used by automobile companies to reproduce the accurate and multi axial stresses in test parts to simulate the real loading conditions. The road conditions are simulated in lab by measuring the customer usage data by sensors like Wheel Force transducers, accelerometers, displacement sensors and strain gauges on the vehicle body and suspension parts. The acquired data is simulated in lab condition by generating ‘drive file’ using the response of the above mentioned sensors. Due to non- linear nature of the vehicle parts, transmissibility of load is a complex phenomenon.Due to this complex transmissibility, good simulation at wheel center does not always ensure good correlation at all vehicle locations. The low level of correlation is common at the locations like engine mount, horn bracket and other overhanging brackets which are away from the wheel center. However, during countermeasure evaluation for vehicle development, often it becomes essential to simulate failure at this kind of low correlation zones.In this paper, an experimental approach was applied for focused failure simulation of engine mount which…
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The Analysis of Brake Squeal Noise Related to the Friction Properties of Brake Friction Materials

Hyundai Motor Company-Sang-mok Lee, Jung Hoon Woo, Dong Won Kim
Hyundai Motor Company & KIA Motors Corporation-Younggu Cho
Published 2019-09-15 by SAE International in United States
The friction properties related to squeal noise was analyzed with the development histories and simplified computational method. Firstly, the development histories were investigated especially focusing on the case which the friction materials were modified to improve squeal noise occurrence. Based on the histories, the friction properties of selected friction materials were newly measured using dynamometer. The average friction coefficient levels, torque oscillations, the increment of friction coefficient during full-stop, and etc. were compared with the squeal noise occurrence, and the results showed that increase of friction properties cause production of squeal noise. The result suggested that the size of friction energy was important factors related to triggering the squeal noise. Also, the contact conditions between rotor disc and friction materials were significant factors deciding the noise occurrence. We performed simplified computational analysis using MATLAB program to prove the effect of friction energy on the noise occurrence. The friction surfaces were roughly designed and the distribution of contact plateaus was controlled to simulate different contact conditions. The different contact conditions were designed and performed sliding at…
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