On optimal design of lug joints

N. L. Pedersen*

*Corresponding author for this work

    Research output: Chapter in Book/Report/Conference proceedingConference abstract in proceedingsResearchpeer-review

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    Abstract

    A lug or pinned connection is a simple assembly type that allows for quick assembly and disassembly. The connection have many practical applications both in mechanical and civil engi-neering cases. In the present work the loading on the assembly is assumed to be cyclic so that the design criteria for strength is fatigue, i.e. the maximum stress in the assembly. The usual design of lug joints is controlled by standards, e.g. ISO2338.The stress state is 3 dimensional but still the normal design is constant through the thickness so focus is on the cross sectional design. The typical sectional design is circular and stress concentration factor charts can be found in the literature. The typical assumption used is that it is sufficient to use a 2D model, where a further assumption of either plane stress or plane strain is needed. In practical designs where the thickness is of the same order as the pin diameter we find that there is a significant variation in the stress in the axial direction. The same type of variation is also found in e.g. interference fits, see e.g. [1]. For simplification we will however here neglect the 3D effect on the stress concentration.In the present work the aim is to minimize the stress concentration resulting in an increased strength of the connection. The finite element method (FEM) is used as the analysis tool, and for the successful application a number of aspects must be taken into account, and will be discussed in relation to the design. The different aspects includes:

    -The definition of the stress concentration factor.
    -Mesh refinement (in non-linear contact analysis).
    -Head distance.
    -Poisson's ratio.
    -Plane stress or plane strain.
    -Friction.
    -Clearance.

    The design optimization is performed using shape optimization. For the present optimizationwe have the special case that the shape to be designed is the contact zone. The selected shape parameterization used is the super elliptical one. Further information can be found in [2].
    Original languageEnglish
    Title of host publicationProceedings of the 32nd Nordic Seminar on Computational Mechanics
    EditorsA.H. Niemi, H. Koivurova
    PublisherUniversity of Oulu
    Publication date2019
    Pages131-132
    Publication statusPublished - 2019
    Event32nd Nordic Seminar on Computational Mechanics
    - Lapland Hotels Oulu, Oulu, Finland
    Duration: 24 Oct 201925 Oct 2019
    Conference number: 32
    https://www.oulu.fi/construction/nscm32

    Seminar

    Seminar32nd Nordic Seminar on Computational Mechanics
    Number32
    LocationLapland Hotels Oulu
    Country/TerritoryFinland
    CityOulu
    Period24/10/201925/10/2019
    Internet address

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