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Improvement of Tightening Reliability of Bolted Joints Using Elliptical Confidence Limit in Calibrated Wrench Method

Tokyo Metropolitan University-Soichi Hareyama, Ken-ichi Manabe, Satoshi Kobayashi
  • Technical Paper
  • 2020-01-0218
To be published on 2020-04-14 by SAE International in United States
The calibrated wrench method is used in the tightening of bolts in manufacturing industries in the case of a large amount of tightening work. It is important to apply a large initial clamping force to ensure tightening reliability and prevent self-loosening, fatigue breakage, and so forth. In this method, the clamping force of bolted joints is controlled using a torque wrench. However, since the clamping force is indirectly applied by a wrench, it varies greatly in the case of a large amount of tightening in a factory. Therefore, the calibrated wrench method is not so accurate from the viewpoint of clamping force control. It is conventionally thought that the distribution of the clamping force has the shape of a rhombus. When tightening torque and clamping force are considered to be two independent random variables, the clamping force is distributed within an elliptical confidence limit. Here, we show that the distribution of equivalent stress also has an elliptical confidence limit. Considering the permitted limit for working load stress on a bolted joint, the elliptical distribution has…
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Random Vibration Fatigue Life Assessment of Transmission Control Module (TCM) Bracket Considering the Mean Stress Effect due to Preload

General Motors LLC-Neeraj Carpenter, Sudeep Yesudas, Michael D. Nienhuis
  • Technical Paper
  • 2020-01-0194
To be published on 2020-04-14 by SAE International in United States
Transmission Control Module (TCM) bracket is mounted on the vehicle chassis and is subjected to the random load excitation due to the uneven surface of the road. Assembly of the TCM bracket on the vehicle chassis induces some constant stress on it due to bolt preload, which acts as a mean stress along with the varying random loads. It is important for a design engineer and CAE analyst to understand the effect of all sources of loads on vehicle mount brackets while designing them. The objective of this study is to consider the effect of mean stress in the random vibration fatigue assessment of TCM bracket. The random vibration fatigue analyses are performed for all the three directions without and with consideration of mean loads and results are compared to show the significance of mean stresses in random vibration fatigue life. It was found from this study that mean stress affects the vibration fatigue life and it can increase or decrease the fatigue damage depending upon the nature of the mean stress.
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Quantification of Clamp Loss and Subsequent Loosening of Automotive Hub-Knuckle Joints under Time-Varying Proving Ground Loading

FCA US LLC-Sandip Datta, Parag Nittur
  • Technical Paper
  • 2020-01-0181
To be published on 2020-04-14 by SAE International in United States
Threaded fasteners or bolted joints are used extensively in automotive assemblies. There are standard procedures to evaluate joint performance under block cycles or road loads. The deciding load case for such joint design is slippage analysis of the joint.There are studies done to evaluate the theoretical and experimental behavior of these joints. There are different ways of understanding the interaction between the bolt and the nut under different loading scenarios. However, none have provided a satisfactory method of quantifying bolt loosening or loss of clamp load under cyclic loading, where no slippage is observed.Under varying loads, initial relaxation of the joint is followed by a loss of clamping load. Below a critical value, complete loss of clamping load progresses very rapidly and this results in a loose joint. The loss of clamping load below the critical value happens at a transition stage when both elastic deformations of the bolt as well as external moments contribute to rapid loosening.This study provides an overall understanding of geometric parameters that contribute to sudden loss of clamping load and…
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Prediction of Tow Hook and Bolt Joint strength behavior under abusive load using Virtual Test Simulation Technique

FCA Engineering India Pvt., Ltd.-Venkata Anumala, Roshan N. Mahadule, Suhas Patil
FCA US LLC-Kyle Jump
  • Technical Paper
  • 2020-01-1399
To be published on 2020-04-14 by SAE International in United States
There is an increasing demand for reducing the vehicle development process and minimizing cost due to tough competition in the Automotive market. One of the major focus areas is minimizing the vehicle prototype builds that are required for physical testing during early phases of the vehicle development. Tow hooks are key structural components for the vehicle, which are designed to withstand structural strength performance under various vehicle towing conditions. Typical extreme load scenarios for the vehicle can be towing fully loaded vehicle broken down on uphill road or stuck in wet muddy conditions. To exercise the tow hook structural development in early design phase, it is important to have reliable simulation process. This paper focuses on development of virtual test simulation process that replicates the vehicle level test behavior for tow hook loading. The setup includes local model with necessary part interaction for clevis load applicator, tow hook, bolt joint and front body structure for simulating correct load transfer for tow hook. Non-linear stress analysis approach is chosen to simulate the large deformation and part…
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Dynamic Load Identification for Battery Pack Bolt Based on Machine Learning

China University Of Mining & Technology-Deke Sheng
GAC Automotive Engineering Institute-Yuan Liu
  • Technical Paper
  • 2020-01-0865
To be published on 2020-04-14 by SAE International in United States
Batteries are exposed to dynamic load during vehicle driving. It is significant to clarify the load input of the battery system during vehicle driving for battery pack structural design and optimization. Currently, bolt connection is mostly applied for battery pack constraint to vehicle, as well as for module assembly inside the pack. However, accurate bolt load is always difficult to obtain, while directly force measurement is expensive and time consuming in engineering. In this paper, a precise data driven model based on Elman neural network is established to identify the dynamic bolt loads of the battery pack, using tested acceleration data near bolts. The dynamic bolt force data is measured at the same time with the acceleration data during vehicle running in different driving conditions, utilizing customized bolt force sensors. A data preprocessing method synthesizing Wavelet denoising method and machine learning algorithm is designed to improve model precision under dynamic condition. Parts of the pretreated acceleration and force data that obtained in various driving conditions are employed for model training, while the rest for model…
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Validity Assessment and Calibration Approach for Simulation Models of Energy Efficiency of Light-Duty Vehicles

Toyota Motor North America Inc.-Karim Hamza, Kang-Ching Chu, Ken Laberteaux
University of California Davis-Matthew Favetti, Peter Benoliel, Vaishnavi Karanam, Gil Tal
  • Technical Paper
  • 2020-01-1441
To be published on 2020-04-14 by SAE International in United States
Software tools for simulations of vehicle fuel economy/energy efficiency play an important role strategic decision-making in advanced powertrains. In general, there is a trade-off between the level of detail in a numerical model of a vehicle (higher detail provides better simulation accuracy), and the computational time resources to run the model. However, even with detailed models of a vehicle, there remains some uncertainty about how the vehicle performs in the real-world. Calibration of simulation models versus real-world data is a challenging task due to variations in vehicle usage by different owners. This work utilizes datasets of real-world driving in vehicles that have been equipped with OBD/GPS loggers. The loggers record at fairly high frequency the vehicle speed, road slope, cabin heating/air-conditioning loads, as well as energy/fuel consumption. For six advanced powertrain vehicle models (Bolt, Leaf, Model S, C-Max Energi, Prius Prime, Volt), an assessment is made regarding the accuracy of window-sticker ratings derived from standard dynamometer tests. One key observation is that while window-sticker ratings can be reasonably accurate when considering many trips across different…
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new

STUD, STRAIGHT - 2.5 DIA ENGAGEMENT, A286, MJ METRIC, 6 X 1 - 6 X 1

E-25 General Standards for Aerospace and Propulsion Systems
  • Aerospace Standard
  • MA3379A
  • Current
Published 2020-03-30 by SAE International in United States

SCOPE IS UNAVAILABLE.

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new

FITTING, BOLT, FLARED, 37° SPHERICAL

G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
  • Aerospace Standard
  • AS6075B
  • Current
Published 2020-03-26 by SAE International in United States

Scope unavailable.

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new

BOLT, MACHINE - HEXAGON HEAD, PD SHANK, NICKEL ALLOY (UNS N07001), .1900-32 UNJF-3A

E-25 General Standards for Aerospace and Propulsion Systems
  • Aerospace Standard
  • AS3303B
  • Current
Published 2020-03-26 by SAE International in United States

Scope is unavailable.

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new

BOLT, MACHINE - DOUBLE HEXAGON EXTENDED WASHER HEAD, FULL SHANK, STEEL AMS6322, CADMIUM PLATED, .5625-18 UNJF-3A

E-25 General Standards for Aerospace and Propulsion Systems
  • Aerospace Standard
  • AS9947B
  • Current
Published 2020-03-24 by SAE International in United States

SCOPE IS UNAVAILABLE.