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Training / Education

Introduction to Failure Mode and Effects Analysis for Product and Process

2022-11-08
Failure Mode and Effects Analysis (FMEA) is a systematic method for preventing failure through the discovery and mitigation of potential failure modes and their cause mechanisms. Actions are developed in a team environment and address each high: severity, occurrence or detection ranking indicated by the analysis. Completed FMEA actions result in improved product performance, reduced warranty and increased product quality.
Training / Education

Weibull-Log Normal Analysis Workshop

2022-08-22
RMS (Reliability-Maintainability-Safety-Supportability) engineering is emerging as the newest discipline in product development due to new credible, accurate, quantitative methods. Weibull Analysis is foremost among these new tools. New and advanced Weibull techniques are a significant improvement over the original Weibull approach. This workshop, originally developed by Dr. Bob Abernethy, presents special methods developed for these data problems, such as Weibayes, with actual case studies in addition to the latest techniques in SuperSMITH® Weibull for risk forecasts with renewal and optimal component replacement.
Training / Education

Vehicle Crash Reconstruction Principles and Technology

2022-05-10
Crash reconstruction is a scientific process that utilizes principles of physics and empirical data to analyze the physical, electronic, video, audio, and testimonial evidence from a crash to determine how and why the crash occurred. This course will introduce this reconstruction process as it gets applied to various crash types - in-line and intersection collisions, pedestrian collisions, motorcycle crashes, rollover crashes, and heavy truck crashes. Methods of evidence documentation will be covered. Analysis methods will also be presented for electronic data from event data recorders and for video.
Technical Paper

A Novel Tensile Testing Method to Characterize the Weld Metal Properties for Laser Welded Blank (LWB) with AHSS

2022-03-29
2022-01-0243
The automotive industry applies Laser Welded Blanks (LWB) to increase the material utilization and light-weighting of the vehicle structure. This paper introduces a novel tensile testing method to characterize the hardening behavior of the weld material with a digital image correlation (DIC) and apply it as a constitutive hardening model in forming simulations with the LWBs of GEN3 steel. Formability tests under biaxial conditions were performed with LWB of GEN3 steel. Experimental results were correlated with finite element analysis (FEA) predictions that were conducted with and without the weld material model. The results show the weld material model for the LWB improves the accuracy of FEA predictions of both necking failures on the base metal as well as cracking on the weld.
Technical Paper

Comparing stress gradient and other concepts for fatigue analysis of notched components

2022-03-29
2022-01-0252
Nowadays simulation of the fatigue life is an essential part of the development of components in the automotive and machinery industry. Weak points can be identified fast and reliable with respect to stiffness, strength and lightweight. A pure virtual optimization of the design can be performed without the need of prototypes. Only for the production release a final test is necessary. A lot of parameters influence the fatigue life as the local stress, material, surface roughness, size of the component, temperature etc. Notches have the strongest impact on fatigue life, depending on radius and shape. Stresses at the notch base are increased because the load flow is forced through a reduced cross section, or changes its direction around an inwardly curved edge. But notches cause not only an increase of the local stress. Also, the local fatigue strength is increased because of a support effect from the neighboring areas, where the stress is already reduced.
Technical Paper

Research on Vehicle State Segmentation and Failure Prediction Based on Big Data

2022-03-29
2022-01-0223
Vehicle failure prediction technology is an important part of PHM(Prognostic and Health Management) technology, which is of great significance to the safety of vehicles and to improve driving safety. Based on the vehicle operating data collected by the on-board terminal (T-box) of the telematics system, the research on the state of vehicle failure is conducted. First, this paper conducts statistical analysis on vehicle historical fault data. Preprocessing procedures such as cleaning, integration, and protocol are performed to group the data set. Then, three indexes including recency(R) frequency(F), and days(D) are selected to construct a vehicle security status subdivision system, and K -Means algorithm is utilized to divide different vehicle categories from the perspective of vehicle value. Labeled information of vehicles in different security status are further established.
Technical Paper

A study on editing method of road load spectrum of automobile rubber isolator using time-frequency domain methods

2022-03-29
2022-01-0272
In order to enhance the efficiency of durability testing of automobile parts, a time-frequency domain accelerated editing method of road load time series of rubber mount on powertrain was discussed. Based on Stockwell Transform method and Accumulative Power Spectral Density, a new time-frequency domain accelerated editing method (ST-APSD) was proposed. The accumulative power spectral density was obtained by ST of the load time series signal of automobile powertrain rubber mounting force which is acquired by the real vehicle in the test field. Based on the accumulative power spectral density, the threshold value was proposed to identify and delete the small damage load fragments, and then the acceleration spectrum was obtained.
Technical Paper

The investigation of a contact and element-based approach for Cohesive zone modelling in the simulation of Delamination propagation

2022-03-29
2022-01-0259
The CAE industry always moves towards new ways to improve the productivity, efficiency and to reduce the solution times. Conventional method of Cohesive Zone Modelling has drawback of higher computation and modelling time. Due to this problem, sometimes Engineers need to avoid simulations and rely only on some sort of approximation of crack from previous designs. This approximation can lead to either product failure or overdesign of the product. A new approach is discussed in this paper to simulate crack initiation and propagation with Cohesive Zone Modelling. Conventional method uses Cohesive zone modelling with Hex or Penta elements by assigning material with cohesive properties, which increases computation and modelling time. The new approach models Cohesive zone as contact between two bodies, thus eliminating the need to use cohesive elements which will essentially reduce the computation time as well as modelling time.
Technical Paper

Technical Keynote: Durability Validation for Variable Vehicle Usage

2022-03-29
2022-01-0255
Durability engineering for vehicles is about relating real operational loading to the actual strength of the product and its components. In the first part of this presentation, we show how to calculate failure probabilities and safety factors based on the load and strength distributions. We discuss the uncertainty within the estimations, which is considerably large in case of extremely small failure probabilities as required for safety critical components. In the second part, we focus on modelling and simulating the loads based on real vehicle usage, such that the resulting statistics allows to understand and quantify the usage variability. The idea is, to simulate thousands of vehicle life spans of, say, 300.000 km or 15.000 h of operation each. The input data for such simulations typically consists of a combination of geographic data (like road network, topography, road conditions, traffic data, and points of interest) and properly segmented rich data from measurement campaigns.
Technical Paper

A fatigue life prediction method of rubber material for Automobile vibration isolator under road load spectrum

2022-03-29
2022-01-0253
Automobile rubber isolator was subjected to random load cycle for a long time in the service process, and its main rubber material for vibration isolation was prone to fatigue failure. Since the traditional Miner damage theory overlooked the load randomness, it had a prediction error problem. In order to improve the prediction accuracy of rubber fatigue life, the traditional Miner damage theory was modified by random uncertainty theory to predict the rubber fatigue life under random load. Firstly, the rubber dumbbell-shaped test column, which was vulcanized from rubber materials commonly used in vibration isolators, was taken as the research object. The uniaxial fatigue test of rubber under different strain amplitudes and strain mean values was carried out. Then the fatigue characteristic curve of rubber with equivalent strain amplitude as the damage parameter was established.
Technical Paper

Structure Optimization and Improvement of Commercial Vehicle Control Arm Based on Topology Optimization Method

2022-03-29
2022-01-0266
Automobile control arm is the guide and force transmission component of automobile suspension system, which makes the lightweight design of automobile according to a certain trajectory beneficial to energy saving and emission reduction. In this paper, the structure of the lower control arm of the front McPherson suspension is modeled and cleaned by UG software to simplify the model. The hexahedral shell element is used to establish the finite element model in HyperMesh. Considering the force and constraint conditions of the control arm under three different load conditions, the strength analysis is carried out by using the finite element software. It is found that the control arm is over-designed and has great potential for lightweight. The load and boundary conditions under different working conditions are set in HyperMesh, and the variable density method in topology optimization method is used to optimize the structure of automobile control arm under different working conditions.
Technical Paper

Moisture absorption behavior and hygrothermal aging life prediction for CFRP adhesive-bonded joints

2022-03-29
2022-01-0327
Effects of moisture absorption on the strength degradation, energy absorption and failure mechanism of CFRP laminates and the adhesive-bonded joints in hygrothermal environment were investigated in this work. Experiments of accelerated moisture absorption, uniaxial tension and three-point bending were performed. SEM observations on the CFRP laminates and the fracture surfaces of the CFRP bonded joints were conducted. Strength degradation and failure mechanism induced by moisture absorption were discussed in detail. The results showed that the strength degradation in tension and in three-point bending of the CFRP laminate due to moisture absorption reached 7.4% and 17.1%, respectively. Different response of CFRP laminate and adhesive layer to the moisture determined the failure mode of the adhesive-bonded joints. Suitable match of CFRP laminate and adhesive was very important to make the failure mode of the joint under control.
Technical Paper

An Investigation of the simulation of sintering distortion in a 316L Part manufactured using Bound Metal Deposition 3D printing

2022-03-29
2022-01-0346
Metal binderjetting is a high throughput additive manufacturing process that has the potential to meet the needs of automotive volume production. In many cases, this process requires a sintering post-process to meet final dimensions. Because the sintering stage is performed free standing (i.e. without the use of tooling) and can involve up to a 20% dimensional change from green part to the final part shape, part distortion can be a concern. In this study, the sintering stage of a bridge geometry was simulated under different parameter settings using a Finite Element Analysis. The sensitivity of the simulation to various process parameter inputs was examined. Parts were then produced in 316L using a bound metal deposition and sintering process and compared to prediction. The sintering simulation indicated good agreement with experiment for some dimensions but highlighted the need for additional analysis.
Technical Paper

Innovative vehicle battery pack design approach through multiphysics cells simulation

2022-03-29
2022-01-0267
This paper presents the design procedure of a vehicle battery pack, in terms of electrical and mechanical requirements with an innovative methodology to model Li-ion cells’ thermo-electro-mechanical behaviour. This modelling approach can predict, through FEM analysis, if short circuit happen with consequent generation of fire in case of vehicle crash. This last aspect has several issues related to the multiphysics characteristics of the phenomena due to the fact that battery cells are made up by really thin components and, as consequence, not significant works of an entire deformable battery pack simulation have been found in literature. For this reason, the design approach studied overcomes the classical methodology in which cells’ mechanical behaviour is considered unknown to understand if cell failure appears avoiding over-engineered battery pack structure. At the beginning, a benchmarking activity on existing FEM modelling methodologies of single cells has been conducted.
Technical Paper

A Review of Current Understanding of the Underlying Physics Governing the Interaction, Ignition and Combustion Dynamics of Multiple-injections in Diesel Engines

2022-03-29
2022-01-0445
This work is intended to be a comprehensive technical review of existing literature and a synthesis of current understanding of the governing physics behind the interaction of multiple fuel injectio ns, ignition and combustion behavior of multiple-injections in diesel engines. Multiple-injection is a widely adopted operating strategy applied in modern compression-ignition engines, which involves various combinations of small pre-injections and post-injections of fuel before and after the main injection and splitting the main injection into multiple smaller injections. This strategy has been conclusively shown to improve fuel economy in diesel engines while achieving simultaneous NOx, soot, and combustion noise reduction in addition to a reduction in the emissions of unburned hydrocarbons and CO by preventing fuel wetting and flame quenching at the piston wall.
Technical Paper

An Accurate Analysis Method to Calculate Planetary Gear Set Load Sharing under Non-Torque Load

2022-03-29
2022-01-0653
Given their high-power density, large range of speed change, and reputation of being quieter than counter-shaft gear sets, planetary gear sets (PGS) have advantages to be applied in electric vehicle (EV) applications. Typical rear wheel drive automatic transmissions have only PGS in gearbox, and power is transferred by torque. Most electric drive units (EDU) equipped PGS are like a simplified front wheel drive automatic transmission. PGS is coupled with counter-shaft gear sets normally at planet carrier which has two functions: original planet pinion carrying and additional transfer gear mounting. The latter brings in non-torque power in PGS through the carrier. This condition hasn’t obtained enough attention by automotive gear researchers regarding to PGS load sharing calculation. Excluding non-torque load here causes underestimating gear and bearing uneven loads in both magnitude and variation. In extreme conditions, undersized parts would miss demanding durability requirements.
Technical Paper

Modeling the Effects of Drop Impingement Frequency on Heated Walls at Engine Conditions

2022-03-29
2022-01-0508
Understanding the fundamental details of drop/wall interactions is important to improving engine performance. Most of the drop-wall interactions studies are based on the impact of a single drop on the wall. To accurately mimic and model the real engine conditions, it is necessary to characterize spray/wall interactions with different impingement frequencies at a wide range of wall temperatures. In this study, a numerical method, based on Smoothed Particle Hydrodynamics (SPH), is used to simulate consecutive droplet impacts on a heated wall both below and above Leidenfrost temperature. Impact regimes are identified for various impact conditions by analyzing the time evolution of the post-impingement process of n-heptane drops at different impingement frequencies and wall surface temperatures. At low temperature, crown propagation and merging are dominant at low K-number whereas at high K-number there is significant splashing with the traces of liquid film on the surface.
Technical Paper

Managing Trust along the CAN Bus

2022-03-29
2022-01-0119
Multiple approaches have been created to enhance intra-vehicle communications security over the past three decades since the introduction of CAN. The twin pair differential-mode communications bus is tremendously robust in the face of interference, yet physical access to the bus offers a variety of potential attack vectors whereby false messages and/or denial of service are easy to achieve. This paper seeks to evaluate extensions of a common-mode watermark-based authentication technique recently developed to improve authentication on the CAN bus by considering the watermark as a side-channel communications means for high value information. We also describe a variety of higher layer algorithms, with benefits and pitfalls, for employing the watermark as a physical-layer firewall. All of these results are backed by a software-defined radio (SDR) based hardware testbed.
Technical Paper

Modification of the Lower Limb and the Pelvis for the Pedestrian Dummy

2022-03-29
2022-01-0851
In order to further reduce the pedestrian fatalities, the improvement of pedestrian safety performance of vehicles is needed. One of the way to further understand read-world pedestrian accidents is the evaluation by using a whole-body pedestrian dummy. In the past studies, the leg, the thigh and the pelvis of the pedestrian dummy were developed and improved. However, the requirements for the biofidelity of the pedestrian dummy have been improved in SAE J2782. Therefore, this study aimed to evaluate these responses of the past studies by using new requirements and to modify these parts that didn’t meet them. The force-defection curves from 3-point lateral bending tests for the leg and the thigh were compared with the corridors updated in SAE J2782. The biofidelity of the pelvis was evaluated in dynamic lateral compression tests of the isolated pelvis. The sacrum and the pubis force-deflection curves of the iliac or the acetabulum impact were compared with the corridors.
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