| 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
(författare)
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Squeak and Rattle Prediction for Robust Product Development
- 2020
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Squeak and rattle are nonstationary, irregular and impulsive sounds that happen inside the car cabin. For decades, customer complaints about squeak and rattle have been, and still are, among the top quality issues in the automotive industry. These annoying sounds are perceived as quality defect indications and burden warranty costs to the car manufacturers. Today, the quality improvements regarding the persistent type of sounds in the car, as well as the increasing popularity of electric engines, as green and quiet propulsion solutions, stress the necessity for suppressing annoying sounds like squeak and rattle more than in the past. The technical solution to this problem is to approach it in the pre-design-freeze phases of the product development and by employing design-concept-related practises. To nail this goal, prediction and evaluation tools and methods are needed to deal with the squeak and rattle quality issues upfront in the product development process. The available tools and methods for prediction of squeak and rattle sounds in the pre-design-freeze phase in a new car development process are not yet sufficiently mature. The existing knowledge gap about the mechanisms behind the squeak and rattle sounds, the lack of accurate simulation and post-processing methods, as well as the computational cost of complex simulations are some of the significant hurdles in this immaturity. This research addresses this problem by identifying a framework for prediction of squeak and rattle sounds in the form of a cause and effect diagram. The main domains and the elements and the sub-contributors to the problem in each domain within this framework are determined through literature studies, field explorations and the conducted descriptive studies on the subject. Further, improvement suggestions for the squeak and rattle evaluation and prediction methods are proposed through prescriptive studies. The applications of some of the proposed methods in the automotive industry are shown and examined in industrial problems.
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| 10. |
- Bayani, Mohsen, 1981
(författare)
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Squeak and Rattle Prediction for Robust Product Development in the automotive industry
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Squeak and rattle are nonstationary, irregular, and impulsive sounds that are audible inside the car cabin. For decades, customer complaints about squeak and rattle have been, and still are, among the top quality issues in the automotive industry. These annoying sounds are perceived as quality defect indications and burden warranty costs to the car manufacturers. Today, the quality improvements regarding the persistent type of sounds in the car, as well as the increasing popularity of electric engines, as green and quiet propulsion solutions, stress the necessity for attenuating annoying sounds like squeak and rattle more than in the past. The economical and robust solutions to this problem are to be sought in the pre-design-freeze phases of the product development and by employing design-concept-related practices. To achieve this goal, prediction and evaluation tools and methods are required to deal with the squeak and rattle quality issues upfront in the product development process. The available tools and methods for the prediction of squeak and rattle sounds in the pre-design-freeze phases of a car development process are not yet sufficiently mature. The complexity of the squeak and rattle events, the existing knowledge gap about the mechanisms behind the squeak and rattle sounds, the lack of accurate simulation and post-processing methods, as well as the computational cost of complex simulations are some of the significant hurdles in this immaturity. This research addresses this problem by identifying a framework for the prediction of squeak and rattle sounds based on a cause-and-effect diagram. The main domains and the elements and the sub-contributors to the problem in each domain within this framework are determined through literature studies, field explorations and descriptive studies conducted on the subject. Further, improvement suggestions for the squeak and rattle evaluation and prediction methods are proposed through prescriptive studies. The applications of some of the proposed methods in the automotive industry are demonstrated and examined in industrial problems. The outcome of this study enhances the understanding of some of the parameters engaged in the squeak and rattle generation. Simulation methods are proposed to actively involve the contributing factors studied in this work for squeak and rattle risk evaluation. To enhance the efficiency and accuracy of the risk evaluation process, methods were investigated and proposed for the system excitation efficiency, modelling accuracy and efficiency and quantification of the response in the time and frequency domains. The demonstrated simulation methods besides the improved understanding of the mechanisms behind the phenomenon can facilitate a more accurate and robust prediction of squeak and rattle risk during the pre-design-freeze stages of the car development.
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