| 1. |
- Linnéusson, Gary, et al.
(författare)
-
Towards strategic development of maintenance and its effects on production performance by using system dynamics in the automotive industry
- 2018
-
Ingår i: International Journal of Production Economics. - : Elsevier. - 0925-5273 .- 1873-7579. ; 200, s. 151-169
-
Tidskriftsartikel (refereegranskat)abstract
- Managing maintenance within an economical short-termism framework, without considering the consequential long-term cost effect, is very common in industry. This research presents a novel conceptual system dynamics model for the study of the dynamic behaviors of maintenance performance and costs, which aims to illuminate insights for the support of the long-term, strategic development of manufacturing maintenance. By novel, we claim the model promotes a system's view of maintenance costs that include its dynamic consequential costs as the combined result of several interacting maintenance levels throughout the constituent feedback structures. These range from the applied combination of maintenance methodologies to the resulting proactiveness in production, which is based on the rate of continuous improvements arising from the root cause analyses of breakdowns. The purpose of using system dynamics is to support the investigations of the causal relationships between strategic initiatives and performance results, and to enable analyses that take into consideration the time delays between different actions, in order to support the sound formulation of policies to develop maintenance and production performances. The model construction and validation process has been supported by two large maintenance organizations operating in the Swedish automotive industry. Experimental results show that intended changes can have both short and long-term consequences, and that obvious and hidden dynamic behavioral effects, which have not been reported in the literature previously, may be in the system. We believe the model can help to illuminate the holistic value of maintenance on the one hand and support its strategic development as well as the organizational transformation into proactiveness on the other.
|
|
| 2. |
- Salunkhe, Omkar, 1990, et al.
(författare)
-
Review of Current Status and Future Directions for Collaborative and Semi-Automated Automotive Wire Harnesses Assembly
- 2023
-
Ingår i: Procedia CIRP. - : Elsevier. - 2212-8271 .- 2212-8271. ; 120, s. 696-701
-
Tidskriftsartikel (refereegranskat)abstract
- Wire harnesses are vital for any modern automotive vehicle. They control the basic functions in a vehicle, for example, windshield wipers and critical functions such as sensors, cameras, and autopilot functions. Thus, the quality of wire harness assembly is highly important. Today, wire harnesses are usually assembled manually, which creates unergonomic and tedious working conditions for operators. Traditional and collaborative industrial robots have been identified as possible solutions to overcome challenges faced by operators in this type of assembly. The international research community has proposed many solutions for automating the assembly of wire harnesses in automotive vehicles but despite these solutions, the industry has not been able to adopt a method to automate this assembly process fully or partially. This paper presents a review of findings on robot-assisted wire harness assembly processes based on a systematic literature review. Specifically, the assembly of wire harnesses in Electric Vehicles (EVs). The state-of-the-art review focuses on solutions to improve unergonomic work situations and ensure the quality of assembly operations. Best practices and reasons for the lack of extensive implementation in automotive final assembly systems are described. Further, the paper presents suggestions based on success stories where the automation of the wire harness assembly in automotive vehicles has been realised by leveraging human-centred automation solutions. Based on the findings, this paper identifies the research for future study. The findings also indicate that there is already technology that can support the automation of wire harness assembly processes in EVs but it is crucial to identify the human aspects and the role of humans in the assembly of wire harness assembly process.
|
|
| 3. |
- Carlberger, Thomas
(författare)
-
Adhesive joining for crashworthiness : material data and explicit FE-methods
- 2008
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Today, crash simulations replace crash testing in the product development phase in theautomotive industry. High quality simulations enable shorter product development time andhigher competitiveness. However, increasing requirements regarding emissions andcrashworthiness are demanding optimised material choice in the parts constituting the carbody structure. Lightweight materials are becoming frequently used. Joining dissimilarmaterials is difficult using common joining techniques like spot welding. To this end,adhesive joining is currently gaining popularity not only due to the ability to join dissimilarmaterials, joint integrity and structural stiffness both increase by the use of adhesive joining.Moreover, the number of spot welds may be reduced in hybrid joints.In this thesis, adhesive joints are studied with respect to crashworthiness of automotivestructures. The main task for the adhesive is not to dissipate the impact energy, but to keep thejoint integrity so that the impact energy can be consumed by plastic work of the basematerials. Fracture of adhesives can be accurately modelled by cohesive zones. The dynamicbehaviour of finite element structures containing cohesive zones is studied using a simplifiedstructure. An amplified strain rate is found in the adhesive as compared to the base material.The cohesive zone concept is used in the development of a 2D interphase element. Theaccuracy and time step influence of the interphase element is compared to solutions based oncontinuum element representation of the adhesive. The interphase element is found to predictfracture of the adhesive joint with engineering accuracy and has a small effect on the timestep of the explicit FE method.The cohesive laws for use in the material models of the adhesive have been determined usingdedicated test methods. The double cantilever beam specimen and the end notched flexurespecimen are used with inverse methods to determine cohesive laws in peel and shear,respectively. The cohesive laws are determined for varying temperature, strain rate andadhesive layer thickness. A built up bimaterial beam is designed for testing and simulation ofjoints consisting of bolts, adhesives and combinations of bolts and adhesives, i.e. hybridjoints. The model of the hybrid beam developed was found to be able to predict results fromimpact tests, quantified as maximum load and deformed shape of the beam.
|
|
| 4. |
- Arjomandi Rad, Mohammad, et al.
(författare)
-
Correlation-based feature extraction from computer-aided design, case study on curtain airbags design
- 2022
-
Ingår i: Computers in industry (Print). - : Elsevier. - 0166-3615 .- 1872-6194. ; 138
-
Tidskriftsartikel (refereegranskat)abstract
- Many high-level technical products are associated with changing requirements, drastic design changes, lack of design information, and uncertainties in input variables which makes their design process iterative and simulation-driven. Regression models have been proven to be useful tools during design, altering the resource-intensive finite element simulation models. However, building regression models from computer-aided design (CAD) parameters is associated with challenges such as dealing with too many parameters and their low or coupled impact on studied outputs which ultimately requires a large training dataset. As a solution, extraction of hidden features from CAD is presented on the application of volume simulation of curtain airbags concerning geometric changes in design loops. After creating a prototype that covers all aspects of a real curtain airbag, its CAD parameters have been analyzed to find out the correlation between design parameters and volume as output. Next, using the design of the experiment latin hypercube sampling method, 100 design samples are generated and the corresponding volume for each design sample was assessed. It was shown that selected CAD parameters are not highly correlated with the volume which consequently lowers the accuracy of prediction models. Various geometric entities, such as the medial axis, are used to extract several hidden features (referred to as sleeping parameters). The correlation of the new features and their performance and precision through two regression analyses are studied. The result shows that choosing sleeping parameters as input reduces dimensionality and the need to use advanced regression algorithms, allowing designers to have more accurate predictions (in this case approximately 95%) with a reasonable number of samples. Furthermore, it was concluded that using sleeping parameters in regression-based tools creates real-time prediction ability in the early development stage of the design process which could contribute to lower development lead time by eliminating design iterations.
|
|
| 5. |
- Adamson, Göran, 1958-, et al.
(författare)
-
Feature-based control and information framework for adaptive and distributed manufacturing in cyber physical systems
- 2017
-
Ingår i: Journal of manufacturing systems. - : Elsevier. - 0278-6125 .- 1878-6642. ; 43, s. 305-315
-
Tidskriftsartikel (refereegranskat)abstract
- Modern distributed manufacturing within Industry 4.0, supported by Cyber Physical Systems (CPSs), offers many promising capabilities regarding effective and flexible manufacturing, but there remain many challenges which may hinder its exploitation fully. One major issue is how to automatically control manufacturing equipment, e.g. industrial robots and CNC-machines, in an adaptive and effective manner. For collaborative sharing and use of distributed and networked manufacturing resources, a coherent, standardised approach for systemised planning and control at different manufacturing system levels and locations is a paramount prerequisite.In this paper, the concept of feature-based manufacturing for adaptive equipment control and resource-task matching in distributed and collaborative CPS manufacturing environments is presented. The concept has a product perspective and builds on the combination of product manufacturing features and event-driven Function Blocks (FB) of the IEC 61499 standard. Distributed control is realised through the use of networked and smart FB decision modules, enabling the performance of collaborative run-time manufacturing activities according to actual manufacturing conditions. A feature-based information framework supporting the matching of manufacturing resources and tasks, as well as the feature-FB control concept, and a demonstration with a cyber-physical robot application, are presented.
|
|
| 6. |
- Arjomandi Rad, Mohammad, 1987, et al.
(författare)
-
Image regression-based digital qualification for simulation-driven design processes, case study on curtain airbag
- 2023
-
Ingår i: Journal of engineering design (Print). - : Taylor & Francis. - 0954-4828 .- 1466-1837. ; 34:1, s. 1-22
-
Tidskriftsartikel (refereegranskat)abstract
- Today digital qualification tools are part of many design processes that make them dependent on long and expensive simulations, leading to limited ability in exploring design alternatives. Conventional surrogate modelling techniques depend on the parametric models and come short in addressing radical design changes. Existing data-driven models lack the ability in dealing with the geometrical complexities. Thus, to address the resulting long development lead time problem in the product development processes and to enable parameter-independent surrogate modelling, this paper proposes a method to use images as input for design evaluation. Using a case study on the curtain airbag design process, a database consisting of 60,000 configurations has been created and labelled using a method based on dynamic relaxation instead of finite element methods. The database is made available online for research benchmark purposes. A convolutional neural network with multiple layers is employed to map the input images to the simulation output. It was concluded that the showcased data-driven method could reduce digital testing and qualification time significantly and contribute to real-time analysis in product development. Designers can utilise images of geometrical information to build real-time prediction models with acceptable accuracy in the early conceptual phases for design space exploration purposes.
|
|
| 7. |
- Barrera Diaz, Carlos Alberto, 1987-
(författare)
-
Simulation-based multi-objective optimization for reconfigurable manufacturing systems : Reconfigurability, manufacturing, simulation, optimization, RMS, multi-objective, knowledge discovery
- 2023
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In today’s global and aggressive market system, for manufacturing companies to remain competitive, they must manufacture high-quality products that can be produced at a low cost; they also must respond efficiently to customers’ predictable and unpredictable needs and demand variations. Increasingly shortened product lifecycles, as well as product customization degrees, lead to swift changes in the market that need to be supported by capable and flexible resources able to produce faster and deliver to the market in shorter periods while maintaining a high degree of cost-efficiency. To cope with all these challenges, the setup of production systems needs to shift toward Reconfigurable Manufacturing Systems (RMSs), making production capable of rapidly and economically changing its functionality and capacity to face uncertainties, such as unforeseen market variations and product changes. Despite the advantages of RMSs, designing and managing these systems to achieve a high-efficiency level is a complex and challenging task that requires optimization techniques. Simulation-based optimization (SBO) methods have been proven to improve complex manufacturing systems that are affected by predictable and unpredictable events. However, the use of SBO methods to tackle challenging RMS design and management processes is underdeveloped and rarely involves Multi-Objective Optimization (MOO). Only a few attempts have applied Simulation-Based Multi-Objective Optimization (SMO) to simultaneously deal with multiple conflictive objectives. Furthermore, due to the intrinsic complexity of RMSs, manufacturing organizations that embrace this type of system struggle with areas such as system configuration, number of resources, and task assignment. Therefore, this dissertation contributes to such areas by employing SMO to investigate the design and management of RMSs. The benefits for decision-makers have been demonstrated when SMO is employed toward RMS-related challenges. These benefits have been enhanced by combining SMO with knowledge discovery and Knowledge-Driven Optimization (KDO). This combination has contributed to current research practices proving to be an effective and supportive decision support tool for manufacturing organizations when dealing with RMS challenges.
|
|
| 8. |
- De Vin, Leo, 1957-
(författare)
-
Credibility of Simulation Results – a Philosophical Perspective on Virtual Manufacturing
- 2012
-
Ingår i: Proceedings of the 13th Mechatronics Forum International Conference. - Linz : TRAUNER Verlag. - 9783990330463 ; , s. 784-791
-
Konferensbidrag (refereegranskat)abstract
- This paper describes the factors that play a role in credibility of simulation results. It focuses on virtual manufacturing and in particular resource simulation as an example. However, a simulation model can be used in a number of different ways. Verification and validation of models is amongst other factors important for credibility. In this area, much work has been carried out in defense research. There are also some striking similarities between virtual manufacturing and information fusion, in particular in the field of human competence development related to credibility of simulations.
|
|
| 9. |
|
|
| 10. |
- Devotta, Ashwin Moris, 1984-, et al.
(författare)
-
Simulation-Based Product Development Framework for Cutting Tool Geometry Design
- 2019
-
Ingår i: Conference Proceedings. - : Stellenbosch University. - 9780797217799 ; , s. 47-52
-
Konferensbidrag (refereegranskat)abstract
- Cutting tool geometry design has traditionally relied on experimental studies; while engineering simulations, to the level of industrial deployment, have been developed only in the last couple of decades. With the development of simulation capability across length scales from micro to macro,cutting tool geometry development includes engineering data development for its efficient utilization. This calls for the design of a simulation-based approach in the design of cutting tool geometry so that the engineering data can be generated for different machining applications (e.g.digital twin). In this study, the needs for engineering model development of different stages of cutting tool design evaluation is assessed. To this end, some of the previously developed engineering models have been evaluated for evaluation of chip form morphology in industrially relevant nose turning process, work piece material behavior modeling and damage modeling for the prediction of chip shape morphology. The study shows the possibility for the developed models to act as building blocks of a digital twin. It also shows the need for engineering model development for different aspects of cutting tool design, its advantages, limitations, and prospects.
|
|
