| 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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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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| 3. |
- 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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| 4. |
- 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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| 5. |
- Berglund, Johan, et al.
(författare)
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Functional tolerancing of surface texture - A review of existing methods
- 2020
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Ingår i: Procedia CIRP. - : Elsevier B.V.. - 2212-8271. ; , s. 230-235
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Konferensbidrag (refereegranskat)abstract
- Surface texture parameters can provide a link between texture, its processing and function. Recent surveys and industrial experience have shown that the ISO 25178 areal surface texture parameters have not received the level of traction in industry that was predicted when introduced despite the fact that the areal parameters were predicted to have more functionally relevant characterisations than the ISO 4287 profile parameters. The objective of the paper is to enable more functionally relevant specifications of surface texture to be taken up by industry and the scientific community by increasing the knowledge of the ISO 25178 texture and novel feature parameters, and their potential use, as well as knowledge about methods for establishing functionally relevant surface texture specifications. In the paper, existing methods for functional tolerancing of surface texture are reviewed and discussed, examples of applications are given and a direction for continued research is presented. © 2020 The Authors
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| 6. |
- Berglund, Johan, et al.
(författare)
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Industrial needs and available techniques for geometry assurance for metal AM parts with small scale features and rough surfaces
- 2018
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Ingår i: Procedia CIRP. - : Elsevier B.V.. - 2212-8271. ; , s. 131-136
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Konferensbidrag (refereegranskat)abstract
- From an industrial perspective this paper aims to explore the state of the art regarding GD&T for metal additive manufacturing, specifically regarding product definition and inspection. The available techniques for geometry assurance for parts with small scale features and rough surfaces are evaluated in terms of suitability for the task and readiness for industrial implementation. It is found that many of the remaining challenges seem to be related to processing of data rather than obtaining data. Current difficulties are related to issues such as calibration, surface determination and defining the most relevant parameters to tolerance and inspect.
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| 7. |
- Bohlin, Robert, 1972, et al.
(författare)
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Data Flow and Communication Framework Supporting Digital Twin for Geometry Assurance
- 2018
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Ingår i: ASME 2017 International Mechanical Engineering Congress and Exposition. ; 2
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Konferensbidrag (refereegranskat)abstract
- Faster optimization algorithms, increased computer power and amount of available data, can leverage the area of simulation towards real-time control and optimization of products and production systems. This concept — often referred to as Digital Twin — enables real-time geometry assurance and allows moving from mass production to more individualized production. To master the challenges of a Digital Twin for Geometry Assurance the project Smart Assembly 4.0 gathers Swedish researchers within product development, automation, virtual manufacturing, control theory, data analysis and machine learning. The vision of Smart Assembly 4.0 is the autonomous, self-optimizing robotized assembly factory, which maximizes quality and throughput, while keeping flexibility and reducing cost, by a sensing, thinking and acting strategy. The concept is based on active part matching and self-adjusting equipment which improves geometric quality without tightening the tolerances of incoming parts. The goal is to assemble products with higher quality than the incoming parts. The concept utilizes information about individual parts to be joined (sensing), selects the best combination of parts (thinking) and adjust locator positions, clamps, weld/rivet positions and sequences (acting). The project is ongoing, and this paper specifies and highlights the infrastructure, components and data flows necessary in the Digital Twin in order to realize Smart Assembly 4.0. The framework is generic, but the paper focuses on a spot weld station where two robots join two sheet metal parts in an adjustable fixture.
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| 8. |
- Braun, Alina, et al.
(författare)
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Cognitive Quality: An Unexplored Perceived Quality Dimension in the Automotive Industry
- 2020
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Ingår i: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; 91, s. 869-874
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Konferensbidrag (refereegranskat)abstract
- Well known, perceived quality is a game-changer in consumers’ decision-making processes and is seen as one key predictor of a product’s and company’s success. Today, the automotive industry faces challenges not only to deliver superior manufacturing quality in order to excel in perceived quality, but also to induce a positive sensory and cognitive response from its customers. Previous research aimed to quantify and unpick consumers’ perception of quality in order to meet consumer expectations and requirements. Cognitive processes related to product design have been explored in a variety of disciplines, ranging from the design research, specifically in the field of aesthetics, to sociopsychology. In the engineering and manufacturing research field, however, there is a significant gap regarding ‘intangibles’ related to car design. In this conceptual paper, we extend our previous work by presenting the concept of Cognitive Quality as a new dimension of the Perceived Quality Framework (PQF). The PQF, in its turn, illustrates the sensory, attribute-centric engineering viewpoint on quality perception. Therefore, the new Cognitive Quality dimension significantly contributes to the theoretical foundation of perceived quality in engineering and manufacturing research, specifically in the automotive field.
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| 9. |
- Camuz, Soner, 1988, et al.
(författare)
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Contact Variation Optimization for Surface-to-Surface Contacts
- 2017
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Ingår i: Proceedings of International Mechanical Engineering Congress & Exposition. ; 2
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Konferensbidrag (refereegranskat)abstract
- Locating schemes, used to position parts during manufacturing, are usually designed in such a way that the response from the system is minimized. This implies that the position of the fasteners and/or welds are known in an assembly. Today there exist numerous of methods aiming to find an optimal set of locating points to increase the stability of an assembly, for both rigid and compliant parts. However, various industrial applications use surface-to-surface contacts to constrain certain degrees of freedom. This can lead to designs sensitive to geometric and load variations. As the complexity of the surfaces increases, difficulties of allocating geometric tolerances arise. An approach to control this is to keep the contact locations statistically stable. In this paper a methodology is presented where the First-Order reliability Method (FORM) is applied for numerical data, retrieved through Finite Element Analysis (FEA), to ensure that statistically stable contact location are achieved for two bodies with surface-to-suface contact. The FEA data represents how much of the total stress that lies within a given area, sW. The data is continuous and therefore it is assumed that the gradient can be calculated numerically with small steps. The objective function is to maximize sW for n variables. The data set is simulated through Finite Element Analysis using the commercial software Ansys and the results is illustrated on a case study from the machining industry.
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| 10. |
- Camuz, Soner, 1988, et al.
(författare)
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Tolerance analysis of surface-to-surface contacts using finite element analysis
- 2018
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Ingår i: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; 75, s. 250-255
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Konferensbidrag (refereegranskat)abstract
- The accuracy of a cutting tool is dependent on the surface-to-surface contact between the tool body and the insert. Depending on the application, the forces generated during a cutting operation will change in both magnitude and direction. This will alter the contact locations between the tool body and carbide insert thus affecting on both tool life and key characteristics such as cutting performance and productivity. In this article, a methodology is presented to analyse contact variation in the interface between the tool body and the carbide insert. Results presented in this paper can be used for tolerance allocation of surface-to-surface contacts.
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