Plastic hinge: Difference between revisions
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{{distinguish|living hinge}} |
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In the [[structural engineering]] [[beam theory]], '''plastic hinge''' is the deformation of a section of a [[Beam (structure)|beam]] where [[plastic bending]] occurs.<ref>{{Cite book |
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| edition = 2 |
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| publisher = Butterworth-Heinemann |
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| isbn = 0-7506-6221-2 |
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| last = Megson |
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| first = T.H.G. |
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| title = Structural and Stress Analysis, Second Edition |
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| date = 2005-04-29 |
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| ⚫ | }}</ref> In [[earthquake engineering]] plastic hinge is also a type of energy [[Damping ratio|damping]] device allowing [[Plasticity (physics)|plastic]] rotation [deformation] of an otherwise rigid column connection.<ref>[http://mceer.buffalo.edu/education/reu/04Proceedings/12Long_Bergad.pdf Analysis of Rotational Column with Plastic Hinge] Michael Long and Corey Bergad, retrieved November 5, 2006</ref> |
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==Plastic behaviour== |
==Plastic behaviour== |
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In plastic limit analysis of members subjected to bending, it is assumed that an abrupt transition from elastic to ideally plastic behaviour occurs at a certain value of moment, known as [[ |
In plastic [[Limit state design|limit analysis]] of structural members subjected to bending, it is assumed that an abrupt transition from elastic to ideally plastic behaviour occurs at a certain value of moment, known as [[plastic moment]] (M<sub>p</sub>). Member behaviour between M<sub>yp</sub> and M<sub>p</sub> is considered to be elastic. When M<sub>p</sub> is reached, a plastic hinge is formed in the member. In contrast to a [[friction]]less hinge permitting free rotation, it is postulated that the plastic hinge allows large rotations to occur at constant plastic moment M<sub>p</sub>. |
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Plastic hinges extend along short lengths of beams. But detailed analyses have shown that it is sufficiently accurate to consider beams rigid-plastic, with plasticity confined to plastic hinges at points. While this assumption is sufficient for limit analysis, finite element formulations are available to account for the spread of plasticity along plastic hinge lengths<ref> |
Plastic hinges extend along short lengths of beams. Actual values of these lengths depend on cross-sections and load distributions.<ref>{{cite journal |last1=Megalooikonomou |first1=Konstantinos G. |last2=Tastani |first2=Souzana P. |last3=Pantazopoulou |first3=Stavroula J. |title=Effect of Yield Penetration on Column Plastic Hinge Length |journal=Engineering Structures |year=2018 |volume=156 |pages=161–174 |doi= 10.1016/j.engstruct.2017.11.003|bibcode=2018EngSt.156..161M }}</ref> But detailed analyses have shown that it is sufficiently accurate to consider beams rigid-plastic, with plasticity confined to plastic hinges at points. While this assumption is sufficient for [[Limit state design|limit state analysis]], finite element formulations are available to account for the spread of plasticity along plastic hinge lengths.<ref>{{cite journal | doi = 10.1061/(ASCE)0733-9445(2006)132:2(244) | volume=132 | title=Plastic Hinge Integration Methods for Force-Based Beam–Column Elements | year=2006 | journal=Journal of Structural Engineering | pages=244–252 | last1 = Scott | first1 = Michael H. | last2 = Fenves | first2 = Gregory L.| issue=2 }}</ref> |
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By inserting a plastic hinge at a plastic limit load into a statically determinate beam, a kinematic mechanism permitting an unbounded displacement of the system can be formed. It is known as the collapse mechanism. For each degree of static indeterminacy of the beam, an additional plastic hinge must be added to form a collapse mechanism. |
By inserting a plastic hinge at a plastic limit load into a statically determinate beam, a kinematic mechanism permitting an unbounded displacement of the system can be formed. It is known as the collapse mechanism. For each degree of static indeterminacy of the beam, an additional plastic hinge must be added to form a collapse mechanism.{{cn|date=August 2024}} |
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==References== |
==References== |
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Latest revision as of 02:49, 27 August 2024
In the structural engineering beam theory, plastic hinge is the deformation of a section of a beam where plastic bending occurs.[1] In earthquake engineering plastic hinge is also a type of energy damping device allowing plastic rotation [deformation] of an otherwise rigid column connection.[2]
Plastic behaviour
[edit]In plastic limit analysis of structural members subjected to bending, it is assumed that an abrupt transition from elastic to ideally plastic behaviour occurs at a certain value of moment, known as plastic moment (Mp). Member behaviour between Myp and Mp is considered to be elastic. When Mp is reached, a plastic hinge is formed in the member. In contrast to a frictionless hinge permitting free rotation, it is postulated that the plastic hinge allows large rotations to occur at constant plastic moment Mp.
Plastic hinges extend along short lengths of beams. Actual values of these lengths depend on cross-sections and load distributions.[3] But detailed analyses have shown that it is sufficiently accurate to consider beams rigid-plastic, with plasticity confined to plastic hinges at points. While this assumption is sufficient for limit state analysis, finite element formulations are available to account for the spread of plasticity along plastic hinge lengths.[4]
By inserting a plastic hinge at a plastic limit load into a statically determinate beam, a kinematic mechanism permitting an unbounded displacement of the system can be formed. It is known as the collapse mechanism. For each degree of static indeterminacy of the beam, an additional plastic hinge must be added to form a collapse mechanism.[citation needed]
References
[edit]- ^ Megson, T.H.G. (2005-04-29). Structural and Stress Analysis, Second Edition (2 ed.). Butterworth-Heinemann. ISBN 0-7506-6221-2.
- ^ Analysis of Rotational Column with Plastic Hinge Michael Long and Corey Bergad, retrieved November 5, 2006
- ^ Megalooikonomou, Konstantinos G.; Tastani, Souzana P.; Pantazopoulou, Stavroula J. (2018). "Effect of Yield Penetration on Column Plastic Hinge Length". Engineering Structures. 156: 161–174. Bibcode:2018EngSt.156..161M. doi:10.1016/j.engstruct.2017.11.003.
- ^ Scott, Michael H.; Fenves, Gregory L. (2006). "Plastic Hinge Integration Methods for Force-Based Beam–Column Elements". Journal of Structural Engineering. 132 (2): 244–252. doi:10.1061/(ASCE)0733-9445(2006)132:2(244).