東華大學圖書館 |

Multi-Mode Quasi-Static Loading and Interface Reduction to Model Joint Nonlinearity.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Multi-Mode Quasi-Static Loading and Interface Reduction to Model Joint Nonlinearity./
作者:	Singh, Aabhas.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2021,
面頁冊數:	218 p.
附註:	Source: Dissertations Abstracts International, Volume: 83-02, Section: A.
Contained By:	Dissertations Abstracts International83-02A.
標題:	Engineering. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=28645148
ISBN:	9798522900342

Multi-Mode Quasi-Static Loading and Interface Reduction to Model Joint Nonlinearity.
Singh, Aabhas.

Multi-Mode Quasi-Static Loading and Interface Reduction to Model Joint Nonlinearity. - Ann Arbor : ProQuest Dissertations & Theses, 2021 - 218 p.

Source: Dissertations Abstracts International, Volume: 83-02, Section: A.

Thesis (Ph.D.)--The University of Wisconsin - Madison, 2021.

This item must not be sold to any third party vendors.

Nearly all engineering structures are constructed from multiple parts joined by bolts, rivets or other fasteners. Although these joints facilitate construction, they introduce uncertainty into the stiffness and damping associated with the joint, and even nonlinearity. Research has shown that the presence of joints causes the effective natural frequency and damping of modes of vibration of a structure to vary with excitation amplitude. To realize this effect accurately, finite element models of these structures require high-fidelity modeling of the interface, resulting in computationally expensive simulations. To circumvent this issue, reduction techniques are used to create Reduced Order Models (ROMs) that capture the dynamics of the full model. The industry standard approach is to use multi-point constraints (MPC) and/or spring element(s) to reduce the number of degrees of freedom (DOF) that need to be joined at the contact interfaces (spiders). Scalability becomes an issue when multiple joints are present in a system, each requiring a specifically tuned model to capture the dynamics. Furthermore, experimental tests have shown that at large enough amplitudes, one mode influences the vibration of the other, i.e. the modes exhibit coupling due to the nonlinearity in the joints. Typically this has been neglected in structures, since simulating the response requires costly dynamic analyses. This dissertation presents three contributions to the joints community that address these challenges with reduced order modeling and modal coupling of jointed structures.The first contribution presents two rich experimental data-sets that can be used to update numerical models. The first set provides nonlinear data on a new benchmark structure. This data is then used to tune various full and reduced order models such that these models exhibit the same characteristics as the structure. The experimental data collected in the second data-set presents a first study of modal coupling, indicating that some degree of modal coupling is present and observable.The second contribution of this dissertation investigates uncertainty in the industry standard approach. Variations in the size of the contact area and the formulation for the MPC are compared against experimental data obtained from a new benchmark structure. This is contrasted against a novel approach that captures nonlinear effects of joints in a reduced space characterized by the deformation of the interface. This retains the flexibility of the interface by using joint models on non-physical deformation shapes, whereas spiders are done on physical coordinates. This novel method has shown to be effective and efficient at modeling multiple modes of a numerical structure. The last contribution is a novel extension of Quasi-static Modal Analysis (QSMA) to numerically simulate modal coupling. Typical methods are done on a mode-by-mode basis, thus neglecting any interactions between modes. This novel approach explores an alternative where quasi-static forces are applied in the shapes of two or more modes of vibration simultaneously, and the resulting load-displacement curves are used to deduce the effect of other modes on the effective frequency and damping of the mode in question. The quasi-static approach produced reasonable albeit highly conservative bounds on the observed coupled dynamics of a 2D structure and gave insight into the coupling of a structure for which a dynamic analysis is infeasible.

ISBN: 9798522900342Subjects--Topical Terms:

586835
Engineering.
Subjects--Index Terms:

Joints

Multi-Mode Quasi-Static Loading and Interface Reduction to Model Joint Nonlinearity.
LDR:04728nmm a2200397 4500 001 2347166
005 20220719070518.5
008 241004s2021 ||||||||||||||||| ||eng d
020 $a 9798522900342
035 $a (MiAaPQ)AAI28645148
035 $a AAI28645148
040 $a MiAaPQ $c MiAaPQ
100 1 $a Singh, Aabhas. $3 3686380
245 1 0 $a Multi-Mode Quasi-Static Loading and Interface Reduction to Model Joint Nonlinearity.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2021
300 $a 218 p.
500 $a Source: Dissertations Abstracts International, Volume: 83-02, Section: A.
500 $a Advisor: Allen, Matthew S.
502 $a Thesis (Ph.D.)--The University of Wisconsin - Madison, 2021.
506 $a This item must not be sold to any third party vendors.
520 $a Nearly all engineering structures are constructed from multiple parts joined by bolts, rivets or other fasteners. Although these joints facilitate construction, they introduce uncertainty into the stiffness and damping associated with the joint, and even nonlinearity. Research has shown that the presence of joints causes the effective natural frequency and damping of modes of vibration of a structure to vary with excitation amplitude. To realize this effect accurately, finite element models of these structures require high-fidelity modeling of the interface, resulting in computationally expensive simulations. To circumvent this issue, reduction techniques are used to create Reduced Order Models (ROMs) that capture the dynamics of the full model. The industry standard approach is to use multi-point constraints (MPC) and/or spring element(s) to reduce the number of degrees of freedom (DOF) that need to be joined at the contact interfaces (spiders). Scalability becomes an issue when multiple joints are present in a system, each requiring a specifically tuned model to capture the dynamics. Furthermore, experimental tests have shown that at large enough amplitudes, one mode influences the vibration of the other, i.e. the modes exhibit coupling due to the nonlinearity in the joints. Typically this has been neglected in structures, since simulating the response requires costly dynamic analyses. This dissertation presents three contributions to the joints community that address these challenges with reduced order modeling and modal coupling of jointed structures.The first contribution presents two rich experimental data-sets that can be used to update numerical models. The first set provides nonlinear data on a new benchmark structure. This data is then used to tune various full and reduced order models such that these models exhibit the same characteristics as the structure. The experimental data collected in the second data-set presents a first study of modal coupling, indicating that some degree of modal coupling is present and observable.The second contribution of this dissertation investigates uncertainty in the industry standard approach. Variations in the size of the contact area and the formulation for the MPC are compared against experimental data obtained from a new benchmark structure. This is contrasted against a novel approach that captures nonlinear effects of joints in a reduced space characterized by the deformation of the interface. This retains the flexibility of the interface by using joint models on non-physical deformation shapes, whereas spiders are done on physical coordinates. This novel method has shown to be effective and efficient at modeling multiple modes of a numerical structure. The last contribution is a novel extension of Quasi-static Modal Analysis (QSMA) to numerically simulate modal coupling. Typical methods are done on a mode-by-mode basis, thus neglecting any interactions between modes. This novel approach explores an alternative where quasi-static forces are applied in the shapes of two or more modes of vibration simultaneously, and the resulting load-displacement curves are used to deduce the effect of other modes on the effective frequency and damping of the mode in question. The quasi-static approach produced reasonable albeit highly conservative bounds on the observed coupled dynamics of a 2D structure and gave insight into the coupling of a structure for which a dynamic analysis is infeasible.
590 $a School code: 0262.
650 4 $a Engineering. $3 586835
650 4 $a Mechanics. $3 525881
650 4 $a Mechanical engineering. $3 649730
650 4 $a Load. $3 3562902
650 4 $a Tribology. $3 626393
650 4 $a Signal processing. $3 533904
650 4 $a Equilibrium. $3 668417
650 4 $a Dissertations & theses. $3 3560115
650 4 $a Eigen values. $3 3680699
650 4 $a Numerical analysis. $3 517751
650 4 $a Aerospace engineering. $3 1002622
650 4 $a Vibration. $3 544256
650 4 $a Friction. $3 650299
650 4 $a Aircraft. $3 832698
650 4 $a Simulation. $3 644748
650 4 $a Design. $3 518875
650 4 $a Energy dissipation. $3 619627
650 4 $a Methods. $3 3560391
650 4 $a Deformation. $2 lcstt $3 3267001
650 4 $a Interfaces. $2 gtt $3 834756
653 $a Joints
653 $a Mechanical vibrations
653 $a Modal coupling
653 $a Quasi-static modal analysis
653 $a Structural dynamics
690 $a 0537
690 $a 0346
690 $a 0548
690 $a 0389
690 $a 0538
710 2 $a The University of Wisconsin - Madison. $b Engineering Mechanics. $3 3181618
773 0 $t Dissertations Abstracts International $g 83-02A.
790 $a 0262
791 $a Ph.D.
792 $a 2021
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=28645148