Dynamic Simulation and Friction Modeling of Threaded Fastener Joints for Control-Oriented Applications
2026 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]
Industrial tightening processes play a central role in ensuring the reliability, repairability, and resource efficiency of products that rely on threaded fastener joints. The primary functional quantity in such joints is the clamp force, which governs joint reliability but is normally not measured directly during industrial tightening. Instead, tightening systems are predominantly controlled using torque and angle, so that the achieved clamp force must be inferred indirectly. This relation is strongly influenced by friction in the threads and under-head contact, as well as by structural compliance, embedment, and other internal process conditions. Friction varies between specimens and across operating conditions, which limits the robustness of conventional tightening strategies and poses a central challenge for clamp-force-oriented control. These challenges create a need for physically grounded, dynamic simulation models that explicitly account for the coupled behavior of the tightening system and remain suitable for control-oriented analysis.
Dynamic, control-oriented simulation models are developed and assessed for threaded fastener tightening. The tightening system is represented as a coupled rotational and translational dynamic system, in which thread kinematics, frictional losses, joint compliance, phase-dependent joint behavior, and embedment interact during the tightening process. Particular attention is given to the transition from rundown to seating and elastic clamping, and to transient operating conditions such as acceleration, deceleration, dwell phases, break-away, and motion near zero relative velocity. A structured system-level model is first established to capture the dominant torque–angle–clamp-force behavior of the tightening process, including embedment as an explicit internal state. This framework is then used to compare representative friction-model formulations under tightening-relevant conditions, with emphasis on transient dynamic response, numerical robustness, computational effort, and the practical distinguishability of model responses.
The results show that the dynamic model reproduces the principal qualitative features of realistic tightening processes, including the build-up of torque and clamp force across process phases and the influence of phase transitions and friction on the overall response. The friction-model comparison demonstrates that the influence of model formulation is strongly regime-dependent: differences between formulations are small during continuous relative motion, but become pronounced near zero relative velocity, during break-away, and in stick–slip-prone conditions. Several friction-model formulations can reproduce experimentally observed tightening behavior with comparable accuracy when appropriately parameterized. This indicates that the practical predictive limits of dynamic tightening simulations are constrained not only by friction-model structure, but also by parameter uncertainty, calibration ambiguity, process variability, and limited measurement-based distinguishability. The models are therefore most effective as structured simulation environments for analysis, comparison, and method development rather than as exact specimen-specific predictive twins. Overall, the results provide a foundation for future work on clamp-force estimation, observer design, and model-based tightening control.
Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2026. , p. 34
Series
Linköping Studies in Science and Technology. Licentiate Thesis, ISSN 0280-7971 ; 2032
National Category
Control Engineering
Identifiers
URN: urn:nbn:se:liu:diva-223916DOI: 10.3384/9789181185393ISBN: 9789181185386 (print)ISBN: 9789181185393 (electronic)OAI: oai:DiVA.org:liu-223916DiVA, id: diva2:2059964
Presentation
2026-06-12, Ada Lovelace, B Building, Campus Valla, Linköping, 10:15
Opponent
Supervisors
Note
Fuding agencies: This work was performed within the Competence Center SEDDIT (Sensor Informatics and Decision making for the DIgital Transformation), supported by Sweden's Innovation Agency within the research and innovation program Advanced digitalization.
2026-05-132026-05-132026-05-19Bibliographically approved
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