Design and nonlinear modelling of general flexure beams and compliant mechanisms

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dc.contributor.advisorHao, Guangbo
dc.contributor.advisorKelliher, Denis
dc.contributor.authorZhu, Jiaxiangen
dc.contributor.funderChina Scholarship Council
dc.contributor.funderUniversity College Cork
dc.date.accessioned2025-05-12T13:51:57Z
dc.date.available2025-05-12T13:51:57Z
dc.date.issued2024
dc.date.submitted2024
dc.description.abstractA compliant mechanism is a mechanical structure that achieves motion and force transmission through elastic deformation of its flexible components rather than relying on traditional rigid-body joints. Their ability to deliver smooth, repeatable motion with minimal backlash and wear has made them indispensable in practical and technological applications. This research advances the field of compliant mechanisms by addressing critical challenges in nonlinear modeling and design. The primary modeling contributions include a 2D nonlinear general lumped-compliance beam model (GLBM) and a 3D model for general single-translation constraint (GSTC) leaf beams. These parameterized models incorporate a carefully selected set of geometric variables, striking a balance between computational efficiency and configurational versatility. By adjusting these parameters, the models can represent a wide range of compliant mechanism designs, enabling reconfigurable configurations, rapid nonlinear modeling, and efficient multi-objective optimization without unnecessary complexity. On the design side, novel compliant mechanisms are proposed and modeled, including revolute joints, bistable mechanisms, spherical joints, an over-constraint-based nearly-constantamplification ratio compliant amplifier (OCARCM), and a mirror-symmetrical XY compliant parallel manipulator (XY CPM). The GLBM accurately predicts force-displacement behavior in 2D mechanisms, while the GSTC model enables versatile spherical joint design through parametric adjustments. Additionally, the nonlinear modeling of the OCARCM and XY CPM employs a closed-form beam constraint model (BCM), which can be derived from the 2D GLBM to facilitate efficient nonlinear analysis. Comprehensive finite element analysis (FEA) and experimental validation demonstrate strong agreement with analytical models. The GLBM shows 2%–6% error for large deflections, and the GSTC beam remains within 10% error across typical motion ranges. The OCARCM achieves just 1% variability in amplification ratio, outperforming conventional designs. The XY CPM effectively reduces parasitic effects and enhances out-of-plane stiffness while maintaining precision and compactness.
dc.description.statusNot peer revieweden
dc.description.versionAccepted Versionen
dc.format.mimetypeapplication/pdfen
dc.identifier.citationZhu, J. 2024. Design and nonlinear modelling of general flexure beams and compliant mechanisms. PhD Thesis, University College Cork.
dc.identifier.endpage174
dc.identifier.urihttps://hdl.handle.net/10468/17421
dc.language.isoenen
dc.publisherUniversity College Corken
dc.relation.projectChina Scholarship Council- University College Cork PhD Programme (Grant no. 202008300013)
dc.rights© 2024, Jiaxiang Zhu.
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/
dc.subjectCompliant mechanisms
dc.subjectNonlinear modeling
dc.subjectLumped-compliance beam model (GLBM)
dc.subjectSingle-translation constraint (GSTC)
dc.subjectBeam constraint model (BCM)
dc.subjectRevolute joints
dc.subjectBistable mechanisms
dc.subjectSpherical joints
dc.subjectCompliant amplifier (OCARCM)
dc.subjectXY compliant parallel manipulator (XY CPM)
dc.subjectParametric design
dc.titleDesign and nonlinear modelling of general flexure beams and compliant mechanisms
dc.typeDoctoral thesisen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD - Doctor of Philosophyen
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