김경종
57 lines
2.5 KiB
Markdown
57 lines
2.5 KiB
Markdown
---
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type: concept
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title: "Shell Locking Phenomenon"
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complexity: advanced
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domain: computational-mechanics
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aliases:
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- shell locking
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- locking phenomenon
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- membrane locking
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- shear locking
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created: 2026-05-28
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updated: 2026-05-28
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address: c-000045
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tags:
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- concept
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- finite-element-method
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- shell-elements
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- locking
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status: current
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related:
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- "[[On-the-Finite-Element-Analysis-of-Shell-Structures]]"
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- "[[Assumed Transverse Shear Strain Interpolation]]"
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- "[[MITC4 Shell Element]]"
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- "[[Displacement-Based Finite Element Formulation]]"
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- "[[Shell Structure Asymptotic Behavior]]"
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- "[[Uniform Optimal Convergence]]"
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sources:
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- "[[On-the-Finite-Element-Analysis-of-Shell-Structures]]"
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---
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# Shell Locking Phenomenon
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## Definition
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Shell locking is a thickness-dependent finite element error in which a shell element becomes artificially stiff as the shell becomes thin. It appears as underpredicted displacements, stresses, strains, and strain energy, and as poor convergence in thin-shell bending or mixed-dominated problems.
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## How It Works
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The source connects locking to [[Shell Structure Asymptotic Behavior]]. Displacement-based shell elements may fail to approximate the pure bending displacement space of the [[Basic Shell Mathematical Model]]. The result is parasitic membrane or transverse shear strain in states that should be nearly strain-free in those modes.
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The paper distinguishes membrane locking from shear locking. Membrane locking appears in curved shells, while transverse shear locking can appear regardless of curvature when the interpolation cannot represent the thin-shell bending constraint.
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## Remedies
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Common remedies include reduced integration, incompatible or non-conforming modes, ANS, EAS, and MITC-style mixed interpolation. The source treats MITC as a particularly effective family because it interpolates selected tensorial strain components at tying points while trying to retain consistency and ellipticity.
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## Connections
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- [[Assumed Transverse Shear Strain Interpolation]] is the targeted shear-locking remedy used in the four-node shell thread.
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- [[MITC4 Shell Element]] is the practical low-order shell element thread that uses mixed interpolation to control locking.
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- [[Uniform Optimal Convergence]] is the desired behavior after locking has been controlled.
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- [[Shell Element Benchmark Testing]] describes how locking should be exposed using convergence curves and thickness variation.
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## Sources
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- [[On-the-Finite-Element-Analysis-of-Shell-Structures]]
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