| 1. |
- Bayani, Mohsen, 1981, et al.
(författare)
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A strategy for developing an inclusive load case for verification of squeak and rattle noises in the car cabin
- 2021
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Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191 .- 2688-3627.
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Konferensbidrag (refereegranskat)abstract
- Squeak and rattle (S&R) are nonstationary annoying and unwanted noises in the car cabin that result in considerable warranty costs for car manufacturers. Introduction of cars with remarkably lower background noises and the recent emphasis on electrification and autonomous driving further stress the need for producing squeak- and rattle-free cars. Automotive manufacturers use several road disturbances for physical evaluation and verification of S&R. The excitation signals collected from these road profiles are also employed in subsystem shaker rigs and virtual simulations that are gradually replacing physical complete vehicle test and verification. Considering the need for a shorter lead time and the introduction of optimisation loops, it is necessary to have efficient and inclusive excitation load cases for robust S&R evaluation. In this study, a method is proposed to truncate and identify the important parts of the different road profiles that are often used for S&R physical verification and then merge them to develop one representative excitation load case. The criteria for signal truncation were based on the S&R risk and severity metrics calculated from the vibration response at the critical interfaces for S&R. the method was used in a case study involving the instrument panel of a passenger car. Results of the virtual simulation and the rig tests were compared with the complete vehicle test. The proposed synthesised signal generation strategy was validated by physical testing through measuring vibration signals. The results supported the possibility of replacing multiple S&R excitation signals with one single representative inclusive signal, while the quality of S&R risk prediction from the system response was maintained. The outcome of this work can lead to a more efficient physical and virtual S&R verification in the development process of passenger cars.
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| 2. |
- Bayani, Mohsen, 1981, et al.
(författare)
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Analysis of sound characteristics to design an annoyance metric for rattle sounds in the automotive industry
- 2021
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Ingår i: International Journal of Vehicle Noise and Vibration. - 1479-148X .- 1479-1471. ; 17:17, s. 3-4
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Tidskriftsartikel (refereegranskat)abstract
- In this research, a new objective psychoacoustic metric for predicting the annoyance level of the rattle sounds in the automotive industry is proposed. Compared with previous works, in addition to the standard psychoacoustic metrics, new statistical measures of average relative prominence and normalised number of peaks are introduced and employed. A subjective listening test was conducted to elicit the perception of annoyance level of the rattle sounds by the car users. The subjective test was based on the new method of paired comparison with indirect magnitude estimation, developed and proposed in this study by the authors. The accuracy of the metric proposed was checked by the coefficient of determination and error measures. The perceived annoyance metric proposed can be tuned for predicting other similar impulsive sounds in other disciplines as well. Also, the authors would like to encourage other researchers to employ the subjective test method proposed for other similar applications.
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| 3. |
- Bayani, Mohsen, 1981, et al.
(författare)
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Effect of temperature variation on the perceived annoyance of rattle sounds in the automotive industry
- 2019
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Ingår i: Proceedings of the International Congress on Acoustics. - 2226-7808 .- 2415-1599. - 9783939296157 ; 2019-September, s. 4383-4390
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Konferensbidrag (refereegranskat)abstract
- Product quality improvements and electrification in automotive industries, denote the growing need for squeak and rattle free cars. Studying the relation between main sources of rattle sound, like temperature changes and the emitted sound can help to improve the design robustness. In this research, the effect of temperature on the perceived annoyance level of rattle sounds that are generated from selected material pairs from the car cabin is studied. The sound stimuli were collected from a rattle test apparatus by binaural technology in laboratory condition, by a parameter study on temperature, gap and material pairs. Estimated annoyance levels, using the psychoacoustic metric developed through a subjective listening survey, show that perceived annoyance of rattle sounds varies differently for various materials in different ambient and boundary conditions. Employing this approach can lead to a rattle sound database for material pairs to be incorporated with geometry variation results for requirement setting and design robustness improvements in the early development phases of passenger cars before the physical prototypes are available.
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| 4. |
- Bayani, Mohsen, 1981, et al.
(författare)
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Empirical characterisation of friction parameters for non-linear stick-slip simulation to predict the severity of squeak sounds
- 2021
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Ingår i: SAE International Journal of Vehicle Dynamics, Stability, and NVH. - : SAE International. - 2380-2162 .- 2380-2170. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- Squeak and rattle (S&R) are nonstationary annoying sounds inside the car cabin that impose high warranty costs on car manufacturers. The need for taking S&R preventing measures and the maturity level and cost considerations of the physical prototypes during the pre-design-freeze stages justifies the use of virtual simulation methods. Squeak is a friction-induced high-frequency sound that is attributed to the stick-slip friction phenomenon. The importance of the friction parameters in the squeak severity prognosis is analytically and experimentally mentioned in the literature. However, studying the variation of these parameters respecting the changes in loading and driving conditions with the aim of application in virtual simulations has remained limited or too simplistic. In this work, the rate weakening effect of the friction coefficient curve was involved in the nonlinear finite element simulation of stick-slip events by an exponential decay formulation. The approximated squeak severity by the virtual simulations for selected material pairs agreed with the empirical results from a flexural stick-slip test bench. From the empirical stick-slip data, the dependence of the squeak severity on the friction decay coefficient and the difference of static and kinetic friction coefficients at low and high normal loads were observed, respectively. The relativity of friction parameters on the test conditions demands a dynamic updating of the friction model that can be achieved by polynomial or exponential approximations. Also, the observed polynomial relationship between the squeak severity and the operational conditions can be used to estimate the squeak severity from the linear dynamic simulation results. The outcome of this work can help to better understand the influence of the friction modelling parameters and their variation respecting the operational conditions. This can facilitate a more accurate prediction of squeak risk by employing virtual simulation tools in the pre-design-freeze stages of car development.
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| 5. |
- Bayani, Mohsen, 1981, et al.
(författare)
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Finite Element Model Reduction Applied to Nonlinear Impact Simulation for Squeak and Rattle Prediction
- 2020
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Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191 .- 2688-3627. ; 3:2, s. 1081-1091
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Tidskriftsartikel (refereegranskat)abstract
- Increasing demand for simulation accuracy often leads to increased finite element model complexity, which in turn, results in higher computational costs. As a provision, component mode synthesis approaches are employed to approximate the system response by using dynamic substructuring and model reduction techniques in linear systems. However, the use of available model reduction techniques in nonlinear problems containing the contact type of nonlinearities remains an interesting topic. In this paper, the application of a component mode synthesis method in squeak and rattle nonlinear simulation has been investigated. Critical regions for squeak and rattle of the side door model of a passenger car were modelled by nonlinear contact definition in finite element simulation. Craig-Bampton model reduction method was employed to substructure the finite element model while keeping the nonlinear contacts in the model. The model response was evaluated using the modal assurance criterion, frequency response analysis and contact force magnitude in comparison with the baseline model. Results showed that a great reduction in computational time (about 98%) can be achieved while the accuracy of the system response was maintained at an acceptable range for the intended application for squeak and rattle simulation. Although the prediction of impact events in time was done accurately, the contact force magnitude was estimated with average error of 2.5% to 22%, compared with the baseline results. The outcomes of the study show that to empower squeak and rattle prediction by including contact interfaces in finite element simulations, implementation of the model reduction approach can compensate the simulation cost.
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| 6. |
- Bayani, Mohsen, 1981, et al.
(författare)
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Geometric robustness and dynamic response management by structural topometry optimisation to reduce the risk for squeak and rattle
- 2022
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Ingår i: Design Science. - : Cambridge University Press (CUP). - 2053-4701. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Historically, squeak and rattle (S&R) sounds have been among the top quality problems and a major contributor to the warranty costs in passenger cars. Geometric variation is among the main causes of S&R. Though, geometric variation analysis and robust design techniques have been passively involved in the open-loop design activities in the predesign-freeze phases of car development. Despite the successful application of topometry optimisation to enhance attributes such as weight, durability, noise and vibration and crashworthiness in passenger cars, the implementation of closed-loop structural optimisation in the robust design context to reduce the risk for S&R has been limited. In this respect, the main obstacles have been the demanding computational resources and the absence of quantified S&R risk evaluation methods. In this work, a topometry optimisation approach is proposed to involve the geometric variation analysis in an attribute balancing problem together with the dynamic response of the system. The proposed method was used to identify the potential areas of a door component that needed structural reinforcement. The main objective was to enhance the design robustness to minimise the risk for S&R by improving the system response to static geometrical uncertainties and dynamic excitation.
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| 7. |
- Bayani, Mohsen, 1981, et al.
(författare)
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Nonlinear modelling and simulation of impact events and validation with physical data
- 2018
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Ingår i: Proceedings of ISMA 2018 - International Conference on Noise and Vibration Engineering and USD 2018 - International Conference on Uncertainty in Structural Dynamics. - : KU Leuven - Departement Werktuigkunde. - 9789073802995 ; , s. 4427-4441
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Konferensbidrag (refereegranskat)abstract
- Squeak and Rattle are nonstationary sounds that imply quality deficiency in premium cars. In order to enhance prediction and verification capabilities of squeak and rattle problems upfront in product development phases, robust and accurate virtual models are required. In this research, a modelling approach is employed to simulate the nonlinear response of impact events from a rattle-producing machine by finite element analysis. The model comprises nonlinear contact interactions to capture the system response at impact events and is correlated versus experimental data considering the modal and time domain response. A sensitivity study is performed on the parameters of the contact model. System response is formulated in the form of impact kinematic and kinetic components, which are well correlated with rattle sounds in impact events. The parameters with high impact factor are identified. These results can be used to estimate the response with higher accuracy and enhance rattle event prediction capability.
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| 8. |
- Bayani, Mohsen, 1981, et al.
(författare)
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Resonance Risk and Mode Shape Management in the Frequency Domain to Prevent Squeak and Rattle
- 2022
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Ingår i: Journal of Vibration and Acoustics, Transactions of the ASME. - : ASME International. - 1048-9002 .- 1528-8927. ; 144:1
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Tidskriftsartikel (refereegranskat)abstract
- Avoiding quality problems in passenger cars, such as squeak and rattle (S&R), has been a remarkable cost-saving consideration. The introduction of electric engines and autonomous driving is expected to further stress the need for quieter cabins. However, the complexity of S&R events has obstructed the practical treatment of these quality issues in the pre-design-freeze phases of product development. In this study, new quantified frequency-domain metrics are proposed to measure the risk of S&R generation in car subsystems. The proposed metrics measure the resonance risk and the mode shape similarity in the critical interfaces for S&R. The calculations are done based on the system response in the frequency domain. Compared with the time-domain evaluation methods, the knowledge about the system excitation levels is not essential and the calculations are more time-efficient. The proposed metrics can be used in design optimization processes to involve S&R attributes in the pre-design-freeze attribute trade-off activities besides other attributes. In this work, these metrics were used in a previously developed two-stage optimization approach to determine the connection configuration in two industrial cases. As compared with the baseline design, the risk for S&R was reduced by improving the system behavior in terms of resonance risk and mode shape similarity. This was achieved by applying adjustments to the location of the fasteners while maintaining the same general connection configuration concept.
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| 9. |
- Bayani, Mohsen, 1981, et al.
(författare)
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Squeak and rattle prevention by geometric variation management using a two-stage evolutionary optimisation approach
- 2020
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Ingår i: ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE). ; 2B-2020
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Konferensbidrag (refereegranskat)abstract
- Squeak and rattle are annoying sounds that often are regarded as the indicators for defects and quality issues by the automotive customers. Among the major causes for the generation of squeak and rattle sounds, geometric variation or tolerance stack-up is a key contributor. In the assembly process, the dimensional variation in critical interfaces for generating squeak and rattle events can be magnified due to tolerance stackup. One provision to manage the tolerance stack-up in these critical interfaces is to optimise the location of connectors between parts in an assembly. Hence, the focus of this work is to prevent squeak and rattle by introducing a geometric variation management approach to be used in the design phase in the automotive industry. The objective is to identify connection configurations that result in minimum variation and deviation in selected measure points from the critical interfaces for squeak and rattle. In this study, a two-stage evolutionary optimisation scheme, based on the genetic algorithm employing the elitism pool, is introduced to fine-tune the connectors’ configuration in an assembly. The objective function was defined as the variation and the deviation in the normal direction and the squeak plane. In the first stage, the location of one-dimensional connectors was found by minimising the objective function in the rattle direction. In the second stage, the best combination of some of the connectors from the first stage was found to define planar fasteners to optimise the objective function both in the rattle direction and the squeak plane. It was shown that by using the proposed two-stage optimisation scheme, the variation and deviation results in critical interfaces for squeak and rattle improved compared to the baseline results.
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| 10. |
- Bayani, Mohsen, 1981, et al.
(författare)
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Squeak and rattle prevention by geometric variation management using a two-stage evolutionary optimization approach
- 2022
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Ingår i: Journal of Computing and Information Science in Engineering. - : ASME International. - 1530-9827 .- 1944-7078. ; 22:1
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Tidskriftsartikel (refereegranskat)abstract
- Squeak and rattle are annoying sounds that are often regarded as failure indicators by car users. Geometric variation is a key contributor to the generation of squeak and rattle sounds. Optimization of the connection configuration in assemblies can be a provision to minimize this risk. However, the optimization process for large assemblies can be computationally expensive. The focus of this work is to propose a two-stage evolutionary optimization scheme to find the fittest connection configurations that minimize the risk for squeak and rattle. This was done by defining the objective functions as the measured variation and deviation in the rattle direction and the squeak plane. In the first stage, the location of the fasteners primarily contributing to the rattle direction measures is identified. In the second stage, fasteners primarily contributing to the squeak plane measures are added to the fittest configuration from phase one. It was assumed that the fasteners from the squeak group plane have a lower-order effect on the rattle direction measures, compared to the fasteners from the rattle direction group. This assumption was falsified for a set of simplified geometries. Also, a new uniform space filler algorithm was introduced to efficiently generate an inclusive and feasible starting population for the optimization process by incorporating the problem constraints in the algorithm. For two industrial cases, it was shown that by using the proposed two-stage optimization scheme, the variation and deviation measures in critical interfaces for squeak and rattle improved compared to the baseline results.
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