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Hood insulators are widely used in automotive industry to improve noise insulation, pedestrian impact protection and to provide aesthetic appeal. They are attached below the hood panel and are often complex in shape and size. Pedestrian head impacts are highly dynamic events with a compressive strain rate experienced by the insulator exceeding 300/s. The energy generated by the impact is partly absorbed by the hood insulators thus reducing the head injury to the pedestrian. During this process, the insulator experiences multi-axial stress states. The insulators are usually made of soft multi-layered materials, such as polyurethane or fiberglass, and have a thin scrim layer on either side. These materials are foamed to their nominal thickness and are compression molded to take the required shape of the hood. During this process they undergo thickness reduction, thereby increasing their density.

Pulse Width Modulation or PWM has been widely used in traction motor control for electric propulsion systems. The associated switching noise has become one of the major NVH concerns of electric vehicles (EVs). This paper presents a multi-disciplinary study to analyze and validate current ripple induced switching noise for EV applications. First, the root cause of the switching noise is identified as high frequency ripple components superimposed on the sinusoidal three-phase current waveforms, due to PWM switching. Measured phase currents correlate well with predictions based on an analytical method. Next, the realistic ripple currents are utilized to predict the electro-magnetic dynamic forces at both the motor pole pass orders and the switching frequency plus its harmonics. Special care is taken to ensure sufficient time step resolution to capture the ripple forces at varying motor speeds.

This paper is a continuation of previously published technical paper SAE 2022-01-0314. The preceding work described an analytical methodology to predict the vehicle interior trim squeak and rattle issues upfront in the design cycle using a “relative displacement” or “contact force” metric; the methodology was implemented on the center floor console armrest latch using a linear finite element model. The work is logically extended to predict the squeak and rattle issues quantitatively using now an “acoustic noise” metric, this enables a direct comparison with the physical test results and helps to further refine the design best practices. This approach combines Finite Element Method (FEM) and Boundary Element Method (BEM) to estimate structural vibration response and acoustic sound pressure respectively.

This paper presents the design of Interior Permanent Magnet Synchronous motor (IPMSM) using Soft Magnetic Composite (SMC) material for Electric Vehicle (EV) applications. In EV, the electric motor is characterized by high power density, high torque, low weight and cost efficient. The high torque, high power to weight ratio and high mechanical strength Synchronous Motor along with the SMC structures will make it suitable candidate for such an EV application. With this focus the new SMC material Somaloy 3P is proposed as a motor core material. The SMC material is made up of iron powder particle coated with an electrically insulated layer which gives a unique 3D flux property. This material provides low eddy current losses because of high material resistance. The benefits of Somaloy 3P material for design of electric motor are compact, high performance, weight reduction and cost efficient.

Battery Electric Vehicles (BEVs) are becoming more competitive day by day to achieve maximum peak power and energy requirement. This poses challenges to the design of Thermal Interface Material (TIM) which maintains the cell temperature and ensure retention of cell and prevent electrolyte leak under different crash loads. TIM can be in the form of adhesives, gels, gap fillers. In this paper, TIM is considered as structural, and requires design balance with respect to thermal and mechanical requirements. Improving structural strength of TIM will have negative impact on its thermal conductivity; hence due care needs to be taken to determine optimal strength that meets both structural and thermal performance. During various crash conditions, due to large inertial force of cell and module assembly, TIM is undertaking significant loads on tensile and shear directions. LS-DYNA® is used as simulation solver for performing crash loading conditions and evaluate structural integrity of TIM.

As the world is moving towards greener energy solutions, there is a clear transition seen from ICE to EV powertrain solution. The cost of vehicle is primarily controlled by battery pack as it is high capital intense. Though Li-Ion battery is a very promising technology in terms of energy storage and long-term performance, safety of battery is a concern. Battery can undergo self-fire/ thermal runaway due to several factors like aging, internal short, overcharging etc. A numerical investigation is carried out for a conceptual 10S1P prismatic battery pack to model the nail penetration using commercial ANSYS Fluent tool. Vent gas generation has been modelled and its convective effects on Thermal runaway were studied. Vent gas generation is supported through a user defined function which calculates the amount of flow rate that vent gas encounters during thermal runaway.

Elastomers are widely used in many automotive components such as seals, gaskets etc., for their hyperelastic properties. They can undergo large strain and can return to their original state with no significant deformation making them suitable for energy dissipation applications. Most common testing procedures include uniaxial tension, pure shear, biaxial tension and volumetric compression under quasi-static loading conditions. The results from these tests are used to generate material models for different finite element (FE) solvers, such as LS-DYNA. Commonly used material models for elastomers in LS-DYNA are the Ogden Material Model (MAT77), which uses parameter-based approach and the Simplified Rubber Material Model (MAT181), which uses tabulated input data. Prediction of rate dependent behavior of elastomers is gaining interest as, for example, during a crash simulation the components undergo impact under different strain rates.

Interior Permanent Magnet Synchronous Motor (IPMSM) is widely used in Electric Vehicle (EV) applications. In EV, the electric motor is characterized by high power density, high speed, and light weight. The high-speed, high-power density, fault tolerance capability of the IPMSM make it a suitable candidate for such an EV system. The performance improvement of IPMSM during design is highly desirable. With the application of soft magnetic alloy material Hiperco 50A in place of traditional steel material, the performance of the IPMSM can be greatly improved. Compared to the steel material, the Hiperco 50A provides high power density, low core loss and improved efficiency. With this focus, this paper investigates the application of soft magnetic alloy material (Hiperco 50A) in 150 kW power IPMSM.

Squeak and Rattle (S&R) noise in automotive vehicle components is a direct measure of vehicle build quality. With the recent advances in electric propulsion technology the cabin interior has become even more quieter, but S&R remains one of the main noise issues inside the cabin. Consumer surveys such as by J D Power shows that instrument panel, floor console and glove box latch mechanism are some of the most prominent sources of vehicle interior noise. The commonly used design for console lid latch consists of latch pawl preloaded against the console bin in closed condition. The goal of design is to optimize the preload such that the latch remains in contact with the bin under all operating conditions. But inadequate design, poor manufacturing quality control and material degradation causes the loss of preload. Hence, S&R noise emerges due to friction or impact between the parts which induces undesirable vibration and noise.

Electric motor whine is one of the main noise sources of hybrid and electric vehicles. This paper describes a comprehensive analytical and experimental investigation of permanent magnetic electric motor NVH designs focusing on the contribution from torque ripple (TR) and radial forces (RF). A design-of-experiment method is adopted to design and build candidate motors with (i) high TR and high RF; (ii) high TR and low RF; (iii) low TR and high RF and (iv) low TR and low RF. Four prototype motors are built and tested on motor fixtures to measure dynamic stator forces in radial, tangential and axial directions, track dominant motor orders, and estimate motor Operational Deflection Shapes (ODS). Finite-element based electromagnetic and NVH analyses are performed and correlated to test data. Both tests and analyses confirm reducing TR and RF improves motor NVH performance at dominant pole pass orders.

An automotive heater hose is a nylon-reinforced rubber component which has pressurized coolant flows from engine to Heating, Ventilation Air Conditioning (HVAC) unit and connected at either end using spring or worm clamps. One of the important design failure modes to study is the coolant leakage during hose slip-off scenario that can lead to walk-home failures. Overall dimensional variations, assembly loads and part variations can lead to such scenarios which are crucial to investigate using statistical approach for the robust design. To establish this, an experimental setup was conducted, and an equivalent CAE model was developed using Abaqus Standard. The Finite Element model comprised of an engine union pipe, a rubber heater hose and a spring clamp on the engine side of the vehicle. A suitable hyperelastic model for nylon-reinforced rubber and friction values were used to correctly represent the behavior of heater hose with adjoining steel components.

The battery cell unit and battery module constitute the building blocks for the battery pack in an electric vehicle. It is important to rigorously understand the vibration induced response of the battery pack as it is a prerequisite for the safety of an electric vehicle. An accurate finite element (FE) model plays a key role in predicting the dynamic response of the battery pack simulation. In this paper, finite element analysis (FEA) results are compared with the experimental set up of the battery components and a 60-cell battery module. Using orthotropic elastic constants instead of isotropic properties to model the fiber reinforced polymer (FRP) made battery components produced better modal results correlation. Modal frequency values for the brick components have been improved by 25% to 50%. For the battery module, swapping of mode shape behavior is observed between finite element model and experimental results.