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With increasing efforts towards rapid electrification of powertrains, NVH engineers face new set of challenges. Elimination of the IC engines drastically reduces powertrain borne noise levels but unmasks other existing noises like wind, road, ancillary devices, and squeak & rattle. In addition, the new tonal sounds from electro-mechanical drive systems makes the noise more annoying even though it is lesser quantitatively. In summary, the electrification of powertrains has shifted powertrain NVH development from overall level to sound quality with different targets requiring several electro-mechanical solutions with innovative simulation, testing, and optimization approaches. The purpose of the paper is to present an approach to detect, quantify, and optimize the structure-borne radiated noise of an electric motor due to electromagnetic forces or maxwell pressure exerted by magnetic effects in electric motor.

A low profile high directivity antenna is designed to operate at 5.9 GHz for Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) communications to ensure connectivity in different propagation channels. Patch antennas are still an ongoing topic of interest due to their advantages: low profile, low cost, and ease of fabrication. One disadvantage of the patch antenna is low directivity which results in low range performance. In this paper, we introduce an efficient and novel way to improve the directivity of patch antenna using topology optimization and design of experiments (DoE). Numerical simulations are done using Method of Moments (MoM) technique in the commercially available tool, FEKO. We use global response surface method (GRSM) for double objectives topology optimization. Numerical results show a promising use of topology optimization and DoE techniques for the systematic design of high directivity of low profile single element patch antennas.

Low frequency torsional vibrations can be a significant source of objectionable vehicle vibrations and in-vehicle boom, especially with changes in engine operation required for improved fuel economy. These changes include lower torque converter lock-up speeds and cylinder deactivation. This paper has two objectives: 1) Examine the effect of increased torsional vibrations on vehicle NVH performance and ways to improve this performance early in the program using test and simulation techniques. The important design parameters affecting vehicle NVH performance will be identified, and the trade-offs required to produce an optimized design will be examined. Also, the relationship between torsional vibrations and mount excursions, will be examined. 2) Investigate the ability of simulation techniques to predict and improve torsional vibration NVH performance. Evaluate the accuracy of the analytical models by comparison to test results.

Side impact accounts for a significant source of societal harm, injury and death. To address this issue, Europe and US have introduced legislation to be met for the new vehicle certification. In an effort to meet these regulations and the market demand for safety, Automotive manufacturers have significantly improved vehicle side structure integrity and introduced side impact airbags are for added protection. Today, passenger vans, light truck and sport-utility type vehicles are all popular consumer choices in the US. These vehicles differ significantly from passenger cars in many respects and as such need special design considerations for side airbags. Here, MADYMO-3D model of a generic passenger van / Sport-Utility type vehicle is created and correlated to FMVSS-214 side impact crash test. This model is used to evaluate both door and seat mounted side airbag designs in different orientations at standard test impact condition and at a higher speed.

Explicit method is commonly used in crashworthiness analysis due to its capability to solve highly non-linear problems without numerous iterations and convergence problems. However, the time step for explicit methods is limited by the time that the physical wave crosses the element. Therefore, to avoid large amount of CPU time, the explicit method is usually used for non-linear dynamic problems with a short period of simulation duration. For problems under quasi-static loading conditions at pre-crash and post-crash, implicit method could be more efficient than explicit methods because the required computation time is much shorter. Due to the recent advance of crash codes, which allows both implicit and explicit computations to be performed in the same code, crash engineers are able to use explicit computation for crash simulation as well as implicit computation for some of the pre-crash quasi-static loading or post-crash spring back simulations.

A conceptual study of a control strategy that improves vehicle handling during cornering maneuvers while improving vehicle roll stability is presented. From the vehicle rollover propensity estimated by vehicle states, the proposed control strategy generates different actuation forces between the front and the rear suspensions to meet its handling and roll stability objectives. Simulation results for different vehicle maneuvers show that the proposed algorithm can effectively balance between enhanced handling and rollover stability.

The purpose of this paper is to demonstrate a process to automatically modify and optimize a damping curve for a specific road input. Off road race vehicles are required to maintain high speeds over difficult terrain. This requires large wheel displacements, and shocks tuned to properly damp wheels motions using available wheel travel. Selection of proper damping values allows full use of available suspension travel while minimizing loads and accelerations experienced by the vehicle and driver. Using Altair's MotionView and HyperStudy, a process is demonstrated where a damping curve can be modified based on specific constraints and performance criteria. A full vehicle MotionView model of a generic off-road race car will be simulated driving over a large obstacle. Using optimization techniques within HyperStudy, the characteristics of the damping curve will be modified so that pitch displacement and vertical accelerations on the vehicle and driver are minimized.

Specific energy absorption (SEA) is a quantitative measure of the efficiency of a structural member in absorbing impact energy. For an extruded aluminum crash can, SEA generally depends upon the topology of its cross-section. An investigation is carried out to determine the optimal cross-sectional topologies for maximizing SEA while considering manufacturing constrains such as, permissible die radii, gauges, etc. A comprehensive DOE type matrix of cross-sectional topologies has been developed by considering a wide variety of practical shapes and configurations. Since it is critical to include all feasible topologies, much thought and care has been given in developing this matrix. Detailed finite element crash analyses are carried out to simulate axial crushing of the selected crash cans topologies and the resulting specific energy absorption (SEA) is estimated for each case.

At present, testing elastomeric parts is performed at a level dictated by the users of the testing equipment. No society or testing group has defined a formal standard of testing or a way to calibrate a testing machine. This is in part due to the difficulty involved with testing a material whose properties are in a constant state of flux. To further complicate this issue, testing equipment, testing procedures, fixtures, and a host of other variables including the operators themselves, all can have an impact on the characterization of elastomers. The work presented in this paper looks at identifying some of the variables of testing between machines, load cells, fixtures and operators. It also shows that correlation can be achieved and should be performed between companies to ensure data integrity.

This paper deals with the dynamic characterization of an automotive shock absorber, a continuation of an earlier work [1]. The objective of this on-going research is to develop a testing and analysis methodology for obtaining dynamic properties of automotive shock absorbers for use in CAE-NVH low-to-mid frequency chassis models. First, the effects of temperature and nominal length on the stiffness and damping of the shock absorber are studied and their importance in the development of a standard test method discussed. The effects of different types of input excitation on the dynamic properties of the shock absorber are then examined. Stepped sine sweep excitation is currently used in industry to obtain shock absorber parameters along with their frequency and amplitude dependence. Sine-on-sine testing, which involves excitation using two different sine waves has been done in this study to understand the effects of the presence of multiple sine waves on the estimated dynamic properties.

Many recent developments in automotive technology have resulted from the need to improve fuel economy without sacrificing passenger comfort or safety. This paper documents an effort to reduce the weight of dual-use military/civilian vehicles through the use of innovative design architectures. Specifically, a number of crossmember architecture concepts were developed for the cab floorpan of a light-duty truck. The floorpan is a key structural component of any vehicle, providing a significant contribution to noise, vibration, and harshness parameters such as stiffness and normal modes. Finite element concept models of the baseline cab and concept cabs are used to show that changes in the crossmember architecture can significantly reduce cab weight without compromising structural performance.

Springback study on a Dodge Ram fender outer panel is detailed in this paper. A simple measurement fixture is designed for the panel, wherein non-contact laser scan technology is applied The measurement data are compared with the original CAD design surface and deviation contour maps are obtained. Consistency of measurement is studied at different sections among three samples. Details of FEA simulations are outlined. The comparison between measurement and simulation prediction is summarized. A method to describe the consistency of measurement and the accuracy of simulation prediction is proposed. The targets for measurement consistency and simulation accuracy are verified. A sensitivity analysis is also performed to investigate various simulation input parameters.

The low frequency noise, vibration and harshness (NVH) characteristics play a critical role in the design of vehicle Body-In-White (BIW) structures. Lower order modes influence the structural reliability of the vehicle as well as its ride and handling characteristics. Special consideration is given to ensure that they are spaced apart and not coincident with the frequencies of other vehicle subsystems (e.g. engine and chassis). The added stiffness required to improve the NVH characteristics comes at a cost: increased BIW mass, which affects vehicle dynamics, fuel economy, and point mobilities/structural inertances. This paper documents a procedure to balance BIW build cost, mass and structural performance through an integrated optimization process.

NVH (Noise Vibration & Harshness) is one of the main focus areas during the development of products such as passenger cars or trucks. Physical test methods have traditionally been used to assess NVH, but the necessity for reducing cost and creating a robust solution early in the design process has driven the increased usage of simulation tools. Development of well-defined methods and tools for NVH analysis allows today’s OEMs to have a virtual engineering based development cycle from concept to test. However, a subset of NVH problems including squeak and rattle (S&R) have not been generally focused upon. In a vehicle, S&R is a recurring problem for interior plastic parts such as an instrument panel or door trim. Since 2012, Altair has been developing S&R Director (SnRD), which is a solution that identifies and combats S&R issues by embedding the Evaluation-Line (E-Line) methodology [1] [2].

The current advanced airbag regulation (FMVSS208) requires passenger cars and MPV either to have an automatic suppression system or to meet the LRD requirement on the passenger side. Recently, the car makers are choosing LRD requirement option and developing new LRD passenger airbag system. This paper presents a new methodology for improvement of airbag deployment using experimental and analytical research. The significant parameters were determined from statistical analysis of the experiment data. Basically, to deploy airbag normally, the ultra sonic knife or laser is used to cut the skin layer inside along with the gate line partially, so that deploying airbag can tear gate on instrument panel surface easily. As a result of the number of tests conducted at different conditions, this study was able to determine the range of relevant parameters.

In 2016 the United States Automotive Materials Partnership (USAMP) approached several software vendors with the desire to establish the current state-of-the-art of explicit finite element software for predicting the crash behavior of composite laminates as it relates to application in the automotive industry. The nonlinear explicit solver, RADIOSS, was included in the investigation. Coupon and generic component level test data were supplied to help with the development of material models. The innovation of the approach taken with RADIOSS was to use a numerical Design of Experiments (DOE) to simultaneously fit the various modes of material damage and failure for the composite material. Final correlation was to a series of sled tests completed on a composite bumper and crush cans.

Correct kinematics and compliance modeling of a MacPherson strut suspension requires including the physics of strut rod bending. Various approaches to modeling this bending are available, but these require extensive testing or iteration to achieve reasonable results. This paper presents a new method of modeling strut bending that relies only on easily measured physical characteristics, and yet maintains a high degree of accuracy.

The authors are responsible for the development of a structural 3D shell based bead-to-bead model with sidewalls and belt that separately models all functional layers of a modern tire [4]. In this model, the inflation pressure is modeled as a uniform stress acting normal to the shell’s inner face. The pressure can vary depending on the application: prescribed by the MBS-tool to align to a constant pressure specified for a vehicle or scenario, but it can also be modified dynamically to simulate e.g. a sudden pressure loss in a tire [1]. For many applications, this description of the inflation pressure as a time dependent quantity is sufficient. However, there are applications where it is needed to describe the inflation gas using a dynamic gas equation (Euler or Navier-Stokes). One such example is when the tire model is used in NVH (Noise-Vibration-Harshness) applications where the frequency range extends the 200 Hz range.

CAD integrated tools are accelerating product development by incorporating various aspects of physics through coupling with computational aided engineering (CAE) packages. One of the most challenging coupled-physics is fluid-structure interaction (FSI), which integrates the coupled response of fluid flow with a deforming structure. Many automotive design problems involve some form of FSI, but the coupling effects often are simplified or ignored because of complexity and lack of coupled solution technology. To address this, Altair HyperWorks offers a fully integrated coupled finite element analysis (FEA) capability, so called Direct-Coupled FSI (DC-FSI). The DC-FSI technology, available in HyperWorks 11.0.230, can be used in a wide variety of applications such as hydraulically damped rubber mounts, door seals, shock absorbers, design of valves and rubber diaphragms that restrict flow, and antilock braking systems.

There are various optimization tools available on the market and they are successfully used for improving vehicle component designs in terms of performance and light weight [6][7][9][10]. But when it comes to full vehicle optimization, optimization tools are only one aspect of the entire process. To build up a FEM Model for NVH analysis the assembly process and load case definition play an important role. Both steps are very complex and the chance to make mistakes is very high. After initial analysis the results has to be interpreted to understand the NVH behavior and detect optimization potential. Diagnostic tools could be used to determine modal or panel participation factors or do transfer path analysis. Then components or subsystems could be optimized using numerical optimization tools. For this step often super elements are used to reduce calculation time without losing too much of accuracy.