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Analysis of Parameters Affecting Modal Frequencies in Bolted Joint Connections

Mohammed, Usman Ali
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1535709260529555

Abstract Details

2018, MS, University of Cincinnati, Engineering and Applied Science: Mechanical Engineering.
Different type of joints such as bolted joint, screw joint, riveted joint, sleeve joint and welded joints are used in mechanical assembly to join two or more parts. The selection of a joint type and design depends on the primary function. While performing the primary function of joint, these joints also introduce nonlinearity in the assembly and makes it difficult to predict vibration response of structure. Amplitude dependent modal frequencies and amplitude dependent damping are observed nonlinearities in vibration measurements. Current finite element analysis approaches assume the joint as linear connection when predicting modal frequencies and mode shapes. This can lead to errors in estimation of vibration response, stress calculations and life of the component. A bolted joint connection is considered under present work. The work focuses on analysis of different design and assembly parameters of bolted joint connection. Bolt size, bolt preload, bolt tightening method, flange thickness, grip length are various bolt parameters, that may have effect on dynamic characteristics of structure. Any variation in contact pressure and residual stress state of bolted joint would change vibration behavior of structure. These joint parameters are varied with in practical, design margins and their effect on estimation of modal frequencies and mode shapes are quantified using finite element analysis. A high-fidelity modelling approach is used for finite element parametric study. Residual stress at the joint is another important factor that effects contact pressure and interface nonlinearity. This cannot be modelled using linear modal analysis methods. Residual stress type of tension, compression and shear loads are applied and effect of these loads on modal frequencies of structure are analyzed using high fidelity modelling (HFM) method. Bolted joints behave differently for cold application and hot application. Increase in temperature causes preload variation in the bolt, the modulus of elasticity of material changes. The effect of temperature on bolted joint and its modal frequencies is studied. The error formed due to modelling method is calculated for different linear analytical (finite element) methods compared to the HFM method. Some of finite element results are compared with available experimental results. This information can be used to develop additional factor of safety margins to account for nonlinear effects.
Randall Allemang, Ph.D. (Committee Chair)
David Thompson, Ph.D. (Committee Member)
Yongfeng Xu, Ph.D. (Committee Member)
97 p.
Mechanical Engineering
Bolted joints; Bolt joint modelling approaches; Analytical modal analysis; Bolt joint parameters; Dynamic characteristics; Finite element modelling

Recommended Citations

Citations

  • Mohammed, U. A. (2018). Analysis of Parameters Affecting Modal Frequencies in Bolted Joint Connections [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1535709260529555

    APA Style (7th edition)

  • Mohammed, Usman Ali. Analysis of Parameters Affecting Modal Frequencies in Bolted Joint Connections. 2018. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1535709260529555.

    MLA Style (8th edition)

  • Mohammed, Usman Ali. "Analysis of Parameters Affecting Modal Frequencies in Bolted Joint Connections." Master's thesis, University of Cincinnati, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1535709260529555

    Chicago Manual of Style (17th edition)

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This open access ETD is published by University of Cincinnati and OhioLINK.