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Frank–Read Source

A pinned line defect that repeatedly bows under sufficient drive, sheds a closed defect loop, and retains its anchored segment for another emission cycle.

Version
v1 · 2026-10-03 · History
Domain-specific #
13248
Domain group
Natural Sciences
Origin domain
Chemistry & Materials Science
Aliases
Frank–Read mechanism, Frank-Read source

Core Idea

A Frank–Read source is an anchored line defect that repeatedly emits closed loops. Driving load bows the segment between two pinning sites against its line energy. When it closes and a loop separates, the anchored span remains available to repeat. In a crystal, the defect is a dislocation driven by shear; in an experimentally demonstrated nematic analogue, it is a disclination driven by director twist. The cycle requires loop emission and retention of the source, not merely a line that moves once.[ref-fc77b8438493][ref-fbd3c8d301fd]

Scope of Application

Crystal-plasticity models use pinned dislocation segments on slip planes to explain multiplication of defects under load. Nematic experiments show pinned disclinations bowing and shedding loops under twist. The loop pattern transfers, while defect type, driving law and thresholds differ. Ideal semicircular drawings do not prescribe exact geometry in every material; emitted loops can generate back stress and eventually stop repetition.[ref-fc77b8438493][ref-fbd3c8d301fd]

Clarity

The source is the surviving anchored segment, not the detached loop. This distinguishes a regenerative emitter from dislocation glide, one-off loop nucleation or an obstacle-bypass event. A bowed but unclosed segment is not yet a multiplying source.[ref-fc77b8438493][ref-fbd3c8d301fd]

Manages Complexity

The mechanism organizes material detail into line defect, two anchors, drive/restoration balance, loop closure, and retained source. Material parameters, anisotropy, temperature and neighboring defects determine whether that cycle actually runs. This smaller causal map helps compare systems without mistaking a line-tension idealization for a universal law.[ref-fc77b8438493][ref-fbd3c8d301fd]

Abstract Reasoning

If a pinned line bows, inspect whether it closes into a departing loop and leaves the original span ready to act again. If it only relaxes, the load may be subthreshold; if cycles cease after emissions, test for weakened drive or accumulated back stress. Repetition can increase mobile defects, but one source does not alone prove macroscopic work hardening.[ref-fc77b8438493][ref-fbd3c8d301fd]

Knowledge Transfer

Pinned-line bowing, loop separation and source retention recur literally in crystalline dislocations and nematic disclinations. Each material supplies its own elastic energy and forcing rule.

[^ref-fc77b8438493]: Thomas Hudson, Filip Rindler and Joshua Rydell, “A Quantitative Model for the Frank–Read Dislocation Source Based on Pinned Mean Curvature Flow” (2024), Introduction and §§2–4. [^ref-fbd3c8d301fd]: Cheng Long et al., “Frank–Read Mechanism in Nematic Liquid Crystals”, Physical Review X 14, 011044 (2024), abstract and Article Text.

Neighborhood in Abstraction Space

Frank–Read Source sits in a sparse region of the domain-specific corpus (75th percentile for distinctiveness): few abstractions share its structure, so a faithful description tends to retrieve it precisely.

Family — Structural & Geological Failure Mechanics (23 abstractions)

Nearest neighbors

Computed from structural-signature embeddings · 2026-10-08