Roham Sadeghi Tabar

Improving geometrical quality with joining sequences

Roham Sadeghi Tabar, Doctoral Student at Product Development​ IMS, defends his doctoral thesis. His research interests are in the fields of Geometry Assurance, Computer-Aided Tolerancing, and Optimization.
Online presentation.

Disturbances in the manufacturing and assembly process cause functional and aesthetic problems in the products. Being able to control the disturbances in real-time is the desire of the manufacturing industry to improve quality and reduce waste and costs. 
Joining processes is one of the crucial elements imposing geometrical inaccuracies to the assemblies. The geometrical outcome of the assemblies are predicted using simulations as the costs and material waste do not allow for physical experimentation.
An assembly often consists of several joined parts. The joining sequences impact the geometrical quality considerably. To simulate all the possible alternatives for joining sequences for finding the optimal answer is computationally heavy and expensive.
In this thesis, methods for identifying the optimal joining sequences time-efficiently and accurately are studied. Initially, a rule-based approach is put forward to increase the efficiency of the previously applied algorithms. The joining sequence-quality behavior is approximated using black-box models,  enabling parallel evaluations of the geometrical quality. Based on this finding, a search algorithm for rapid identification of the optimal sequence is presented. Furthermore, a numerical approach to identify the number, location, and sequence of the critical joining points for geometrical quality is introduced. Finally, an efficient simulation approach for evaluating the geometrical quality is proposed.
The results achieved from the studies presented indicate that the simulation-based real-time optimization of the joining sequences is achievable through a parallelized search algorithm and a rapid evaluation of the sequences. The results help control the assembly process, improve the geometrical quality, and save significant computational time.

Public defence
2021-03-04 14:00 -- 17:00
​Examiner: Rikard Söderberg IMS​
Opponent: Professor Jamie Camelio, University of Georgia, United States

Password: 713233​

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Page manager Published: Mon 22 Feb 2021.