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Technical Paper

Parametric Model Order Reduction for Vibroacoustic Metamaterials based on Modal Superposition

2022-06-15
2022-01-0943
Vibroacoustic Metamaterials (VAMM) have recently shown great potential in the elimination of noise and vibration in targeted and tunable frequency regions. The so-called stop band behavior is mainly driven by small resonance structures on a subwavelength scale. Due to the complex material and geometry composition, stochastic methods for uncertainty quantification, model updating, and optimization are necessary in the design and validation process of VAMM. Those methods require to repeatedly solve Finite Element (FE) models with slightly changed parameters and can become computationally challenging for large numerical models. Hence, the need for Parametric Model Order Reduction (PMOR) techniques arise to reduce the computational burden. For VAMM, consisting of many substructures, common PMOR methods based on Component Mode Synthesis (CMS) can become cumbersome to set up and numerically challenging.
Technical Paper

A general framework for the experimental characterization of nonlinearities and its application to a laminated assembly of an electrical motor

2022-06-15
2022-01-0944
As the vehicle industry is in the middle of transformation, the development of electric drives came into focus of engineers. The parameter evaluation of dynamic systems can be cumbersome when having nonlinearity in the structure, for example nonlinear stiffness characteristics. In such case, the standard linear approach, including EMA (Experimental Modal Analysis), modal superposition, FRF measurement (Frequency Response Function) and modal synthesis can not be applied. However, one of the main challenges in addressing nonlinearities is the lack of general tools to approach them. In this paper, a general framework is presented aiming the examination of nonlinearities in a structural dynamic context. The method relies on standard random and sine sweep testing approaches to detect and localize nonlinearities, and on dedicated processing techniques to analyze the data and extract information on the nature of the analyzed nonlinearity.
Technical Paper

On the Calculation of Modal Damping Ratios

2022-06-15
2022-01-0945
The prediction of the sound characteristic of a drive train in early development stages poses a significant competitive advantage to specifically design the sound of e.g. a vehicle. However, at the state of the art, the structural behavior cannot be predicted with satisfactory accuracy due to the various and sensitive mechanisms which contribute to it. In the case of complex structures like electric motors or even complete drive trains, usually model order reduction and linearization techniques like the modal superposition method are employed to reduce the calculation effort and obtain usable models for transient time domain simulations. The three main force contributions which have to be considered are spring forces, inertia forces and damping forces. The former two arise from the Youngs-Modulus and the mass density. Both material parameters are relatively constant over a wide range of boundary conditions and therefor easy to calculate.
Technical Paper

Using Dynamic Substructuring and Component TPA to shape the NVH experience of a full-electric vehicle

2022-06-15
2022-01-5001
In this paper, a fully modular NVH engineering process is shown using Dynamic Substructuring (DS) techniques. The power of combining DS with component-TPA is demonstrated using experimental and numerical data obtained on a fully electric BMW i4 vehicle. Following the component-TPA approach, the electric drive unit (EDU) of the BMW i4 is considered as the vibration source and is described by blocked forces on the interface points to the subframe. The quality of the blocked forces is evaluated using criteria as defined in two recent ISO standards on the topic. The transfer path from the EDU up to the driver’s ear is constructed from the individual component models using Dynamic Substructuring (specifically, the LM-FBS method). The component models include multiple sets of rubber bushings, a subframe and the vehicle trimmed body.
Technical Paper

Characterization and modelling of mounts for electric powertrains

2022-06-15
2022-01-0986
The topic of this paper is to deal with the filtering of medium and high frequency excitations generated by electrified powertrains. It is now recognized that the whining noise generated by the electromagnetic forces and/or the meshing process of the transmission can propagate to the car-body through the rubber mounts. In the design phase, the prediction of the structure borne contribution requires a good knowledge of the dynamic behavior of the rubber mounts. The main issue is the stiffness of the mounts which cannot be modeled as pure springs. In fact, the dynamic behavior of a mount is governed by the material rheology and its internal resonances. The work presented in this paper propose a simulation workflow for the rubber mounts dynamic model and a methodology for the dynamic stiffness measurement including the sensitivity with the preload and with the amplitude of the excitation. Finally, experimental and digital data are compared to assess the simulation method.
Technical Paper

NVH Refinement of Automotive HVAC System

2022-06-15
2022-01-0982
The present day, car performance is more prevailing option to fascinate the buyer in IC and electric passenger vehicle. Acoustic and thermal performance balancing of heating ventilation and air conditioning (HVAC) system within car cabin proves to be critical aspect for automotive OEM. The HVAC system induced noise inside car cabin could be significant discomfort to passengers. For this reason, acoustic quality is becoming increasingly prioritized as a key design issue throughout the entire development process of HVAC system. The paper studies the advancement in using innovative development tools to map the HVAC system noise performance at vehicle level and evaluating at sub component level for noise, vibration and transient flow of refrigerant fluid induced noise with the help of universal buck under controlled condition.
Technical Paper

An alternative Solution to Vehicles Audio System using Inertial Transducers integrated in Trim Parts: Advanced Developments.

2022-06-15
2022-01-0970
The use of inertial transducers instead of traditional loudspeakers is an innovative way to reproduce a quality audio signal in a vehicle cockpit while significantly reducing on-board mass and overall volume of the audio system. This paper presents the development process of a new inertial transducer and its optimization by computer simulation, validated by tests on physical prototypes. The innovation uses a new patented mechanism for suspending and guiding the moving magnetic mass. The principle is based on the assembly of two stages of antagonistic springs, allowing a strict oscillating movement guided orthogonaly with respect to the radiating surface, while reducing very strongly the transverse movements, such as pitch and roll, largely responsible for the loss of quality and distortion of the reproduced audio signal. The resonant frequency related to the impedance of the transducer can also be modified by changing the material and geometry of the suspension springs.
Technical Paper

Modeling and controling acoustic performance of heterogenous materials made of recycled foams

2022-06-15
2022-01-0961
Recycling channels for foam materials, especially mattress foams, are set up. The foams are generally crushed into flakes and then assembled resulting in heterogeneous materials. These materials are more valuable if their properties are controlled. This work focuses on their acoustical properties. First, the properties of initial foams have to be estimated and the assembling process has to be analyzed in order to model the acoustic behavior of the reconstructed heterogeneous materials. The foams flakes are assembled with a binder and compressed during the manufacturing process. This work presents the methodology set up to predict the sound absorption of such heterogeneous materials based on recycled foams, from the estimation of the raw material properties to the final assembly. First, a large number of foams were measured in order to distinguish categories of materials. The data is stored in a database management software in order to perform some statistical analysis.
Technical Paper

Improving the sound transmission loss of an aircraft ceiling panel by locally resonant metamaterials

2022-06-15
2022-01-0960
Lightweight structures and designs have been widely used in a number of engineered structures due to ecological and environmental aspects. Nonetheless, lightweight structures typically experience a reduced noise and vibration reduction performance as a consequence of their increased stiffness-to-mass-ratio. To enhance it, novel low mass and compact countermeasures are often sought to address the challenges of achieving not only a good NVH reduction performance but also maintaining a lightweight design. Recently, locally resonant metamaterials have emerged and shown potential as a lightweight noise and vibration solution with a superior performance in tunable frequency ranges, known as stop bands i.e. frequency regions where free wave propagation is not allowed. These can be achieved by assembling resonant elements that are tuned to the targeted frequency range onto a host structure.
Technical Paper

Polyurethane decoupling foam with variable stiffness and thickness: Insulation performance versus their mechanical and transport properties

2022-06-15
2022-01-0957
The polyurethane (PU) foam is widely used in several automotive noise reduction solutions. The insulation performance of decoupling foam depends on its intrinsic properties: the elastic and transport parameters (Biot parameters). When the transport parameters of foam are controlled, the mechanical properties become dominant for its decoupling function. Globally, a soft foam is better to decouple the vibration from the BIW. However, foam with adequate stiffness is also required due to various reasons (mounting, comfort…). In this work, flat samples of PU foam injected on heavy layer were studied at different foam thickness and hardness. Their Insertion Loss (IL) performances were measured through the Small Cabin system, by both Faurecia and Stellantis, with globally good correlation. The Biot parameters of foam (including the Young’s modulus) and the compression load deflection (CLD - stiffness at high compression rate) of all foam samples were also measured or characterized.
Technical Paper

Reduction of structure-borne tyre/road noise through rubber resonant metamaterials in tyres

2022-06-15
2022-01-0954
This paper demonstrates the application of the resonant metamaterial concept to tyres in order to reduce structure-borne tyre/road noise. Special attention is given to the frequency range between 200-300Hz, containing the first acoustic tyre resonances. These resonances are known to transmit high forces to the wheel-knuckle, leading to structural energy propagating into the vehicle body and, consequently, causing tonal noise in the vehicle compartment and reducing the acoustic comfort of the passengers. By adding recycled rubber resonant elements to the inner liner of the tyre, structural stopband behaviour is achieved in the frequency band of interest. Hence, structural vibrations in the tyre are reduced, resulting in a reduction of the excitation of the first acoustic tyre resonances and, consequently, a mitigation of the transmitted forces to the wheel-knuckle.
Technical Paper

Measurements and Modeling of the Temperature of a Li-polymer Battery Provided with Different Coatings for Heat Dissipation

2022-06-14
2022-37-0013
The battery efficiency is strongly affected by the operating temperature, granting the best performance in a limited range. Great attention is given to the design and the testing of materials for the battery heat dissipation. In the present study, the thermal behavior of a Li-polymer pouch-type cell, which is part of a battery pack for electric vehicles, is investigated. The cell is provided with different coatings of carbon, graphene, and silicone, used in turn, to dissipate the heat generated during the operation in natural convection. The coating is placed on only one side of the battery while the other one is inspected via thermal imaging. Optical diagnostics in the infrared band are used to evaluate the bi-dimensional distribution of the battery surface temperature and the effect of the coating. Different operating conditions are tested by varying the current demand.
Technical Paper

Tailored framework to analyze and interpret LCA's results in automotive lightweighting

2022-06-14
2022-37-0029
Car makers are subject to a strong regulatory pressure to make the industry more environmentally sustainable. In this context, many research and industrial activities have been concentrated in the field of sustainability through the development of innovative materials, manufacturing technologies and production processes. This paper presents a tailored framework for estimating the potential of lightweighting to mitigate the Global Warming Potential (GWP) impact within the automotive sector. The framework is based on the Life Cycle Assessment (LCA) modelling of the use stage and it is able to evaluate the effects of lightweight solutions in the application to a wide range of cars, both in terms of propulsion technologies (Internal Combustion Engine Vehicles, ICEVs, and Battery Electric Vehicles, BEVs) and vehicle segments. In addition, the assessment framework can estimate the effect of different electricity grid mixes when modelling the production of energy consumed by BEVs.
Technical Paper

Advanced glazing solutions for improved energy consumption and thermal comfort in transportation vehicles: numerical and experimental evidences.

2022-06-14
2022-37-0024
In order to reach carbon neutrality targets in 2050 we need to decrease energy consumption in all our activities and to work on the optimization of the vehicles energy management. Electric vehicles will drive us to lower CO2 emissions, however an optimized energy management is needed to increase vehicle mile range and to reach an acceptable level of thermal comfort during all seasons and in each continent. In particular, the thermal envelope has to be improved to minimize the HVAC consumption thus increasing vehicles autonomy. Especially in vehicles with single panes, the glazed surface is the weak point of the thermal envelope and for this reason it is a powerful leverage for improvement. Nowadays several solutions exist and innovative glazing contributes to reach the best system compromise in terms of vehicle cost, weight and energy consumption. Glass can be functionalized with thin coatings that increase thermal insulation without affecting the product aesthetics.
Technical Paper

Lightweight Design and Additive Manufacturing of a Fatigue-Critical Automotive Component

2022-06-14
2022-37-0026
Metal additive manufacturing is finding growing applicability in motorsports and high performance car sectors. Laser-Powder Bed Fusion (L-PBF) is the most developed AM technology for metals producing near-net-shape components of complex geometry that achieve outstanding lightweight targets. For these industrial sectors, aluminum alloys, AlSi10Mg among them, are especially relevant and widely used because readily processed with the industrial-grade equipment. A key issue in the widespread industrial acceptability of L-PBF is the structural integrity of these lightweight components when subjected to dynamic loading conditions because it requires in-depth knowledge of the fatigue behavior of L-PBF aluminum under the combined effect of stress gradients, residual stresses, surface condition and process-induced internal defects.
Technical Paper

Lightweight components manufactured with in-production composite scraps: mechanical properties and application perspectives

2022-06-14
2022-37-0027
In the last years, the design in the automotive sector is mainly led by emission reduction and circular economy. To satisfy the first perspective, composites materials are being increasingly used to produce lightweight structural and semi-structural components. However, the automotive mass production arises the problem of the end-of-life disposal of the vehicle and the reduction of the wastes environmental impact. The circular economy of the composite materials has therefore become a challenge of primary importance for car manufacturers and tier 1 suppliers. It is necessary to pursue a different economic model, combining traditional raw materials with the intensive use of materials from recycling processes. New technologies are being studied and developed concerning the reuse of in-line production scraps with out-of-autoclave process that makes them desirable for high production rate applications.
Technical Paper

Medical Cargo Delivery using Blockchain Enabled Unmanned Aircraft Systems

2022-05-26
2022-26-0006
Significant growth of Unmanned Aerial Vehicles (UAV) has unlocked many services and applications opportunities in the healthcare sector. Aerial transportation of medical cargo delivery can be an effective and alternative way to ground-based transport systems in times of emergency. To improve the security and the trust of such aerial transportation systems, Blockchain can be used as a potential technology to manage, operate and monitor the entire process. In this paper, we present a blockchain network solution based on Ethereum for the transportation of medical cargo such as blood, medicines, vaccines, etc. The smart contract solution developed in solidity language was tested using the Truffle program. Ganache blockchain test network was employed to host the blockchain network and test the operation of the proposed blockchain model. The suitability of the model is validated in real-time using a UAV and all the flight data are captured and uploaded into the blockchain.
Technical Paper

Tuning of Blade Natural Frequencies Outside High Excitation Region by using Ceramic Particle Reinforced Composite Materials for a Typical Gas Turbine Engine Compressor Blade

2022-05-26
2022-26-0003
Composite materials have time and again proven to be highly useful, especially in the aerospace industry with the increasing need for light-weight materials albeit with high stiffness to strength ratios. The Ceramic Particle Reinforced Composites can be effectively utilized in tuning the natural frequencies of components by varying the volume fractions up to 40% with the help of Representative Volume Element (RVE) / Unit Cell Models as explained in Reference [1]. The aim of this paper is to tune the natural frequencies of a typical blade used in a gas turbine engine by modifying the material properties without changing the design profile significantly. The design profiles of blades are arrived at after a lot of engineering iterations from aerodynamics stability point of view and are also finalized based on meeting key performance parameters.
Technical Paper

Research on the Performance of Composite Cantilever Beam under Special Environmental Condition

2022-05-26
2022-26-0005
This paper will focus on the root facture problem of carbon fibre reinforced polymers (CFRP) material of aircraft winglets through ABAQUS simulation analysis regarding the aircraft takeoff and landing from high altitude at the constant and low-temperature experimental analysis and topography analysis. The innovative purpose of this paper is to identify the critical failure stress of the cantilever bending of unidirectional and orthogonal, embedding carbon nanotube reinforcement, and exploring the embedded carbon nanotube regarding the enhancement effect of CFRP aircraft winglet. First of all, the analysis of the force state of the aircraft winglet, the unidirectional and orthogonal CFRP aircraft winglet at normal temperature, and low- temperature cycling is established based on the principle of classic laminates and statics.
Technical Paper

PHM System with Comprehensive Data Analytics to Provide Localized Reasoning for a Failure Prediction

2022-05-26
2022-26-0020
Aircraft system contains components to achieve system functionality, monitor its health and record the health status. The recording health status data provides useful information that will led to the root cause of a system failure. However, the maintenance activities are performed in isolation based on the routine procedure and manual approach. Hence critical system maintenance is ignored because of failure to identify the correct system component causing system health deterioration. Today data analytics are effectively used for predictive health management. With the large amount of data collected in the avionics systems it is difficult finalize the list of the parameters that might be critical for data analytics and prognostic health monitoring.
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