Scholarlink

Background <p>Nacre, or mother-of-pearl, is renowned for its exceptional toughness and energy-dissipating capabilities, attributed to its hierarchical structure of overlapping aragonite tablets bonded by a compliant biopolymer matrix. While tablet sliding has long been proposed as a key toughening mechanism, the reversibility of such sliding under mechanical loading and its strain-dependent behavior remain poorly quantified.</p> Objective <p>This study aims to investigate the formation and recovery of dilation bands in nacre, regions where tablet assemblies slide and separate during deformation. The work seeks to determine the strain threshold for reversible deformation and provide new insights into how nacre’s energy dissipation mechanisms operate.</p> Methods <p>Nacre beams were prepared from <i>Haliotis rufescens</i> shells and subjected to both <i>ex-situ</i> and <i>in-situ</i> three-point bending tests, the latter within a scanning electron microscope (SEM). High-magnification imaging was employed to monitor tablet gap formation and closure at incremental deflection stages. Tablet gap widths and their propagation depth were quantified as a function of applied strain using image analysis techniques.</p> Results <p>Localized dilation bands that formed near the tensile surface under applied bending do so under plane stress conditions. This deformation mechanism redistributes the applied stress locally, effectively reducing stress concentrations and suppressing crack initiation. This work presents direct evidence of large-scale recovery of tablet sliding in nacre, which, to our knowledge, has not been reported before. Furthermore, a critical threshold strain of ~ 0.0062 was identified, beyond which residual tablet gaps remained after unloading, marking the onset of irreversible deformation.</p> Conclusions <p>The findings provide two key insights into nacre’s intrinsic mechanisms for mechanical energy dissipation and enhanced damage tolerance. They offer new understanding and design benchmarks for the development of engineered composites aiming to replicate nacre’s exceptional combination of toughness and recoverability.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Reversible Tablet Sliding and Strain-Limited Deformation in Nacre: In-Situ Observations and Threshold Determination

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2025年12月5日

查看全文
  • A. Zhang,
  • H. Price,
  • Y. Chen,
  • B. C. Prorok

摘要

Background

Nacre, or mother-of-pearl, is renowned for its exceptional toughness and energy-dissipating capabilities, attributed to its hierarchical structure of overlapping aragonite tablets bonded by a compliant biopolymer matrix. While tablet sliding has long been proposed as a key toughening mechanism, the reversibility of such sliding under mechanical loading and its strain-dependent behavior remain poorly quantified.

Objective

This study aims to investigate the formation and recovery of dilation bands in nacre, regions where tablet assemblies slide and separate during deformation. The work seeks to determine the strain threshold for reversible deformation and provide new insights into how nacre’s energy dissipation mechanisms operate.

Methods

Nacre beams were prepared from Haliotis rufescens shells and subjected to both ex-situ and in-situ three-point bending tests, the latter within a scanning electron microscope (SEM). High-magnification imaging was employed to monitor tablet gap formation and closure at incremental deflection stages. Tablet gap widths and their propagation depth were quantified as a function of applied strain using image analysis techniques.

Results

Localized dilation bands that formed near the tensile surface under applied bending do so under plane stress conditions. This deformation mechanism redistributes the applied stress locally, effectively reducing stress concentrations and suppressing crack initiation. This work presents direct evidence of large-scale recovery of tablet sliding in nacre, which, to our knowledge, has not been reported before. Furthermore, a critical threshold strain of ~ 0.0062 was identified, beyond which residual tablet gaps remained after unloading, marking the onset of irreversible deformation.

Conclusions

The findings provide two key insights into nacre’s intrinsic mechanisms for mechanical energy dissipation and enhanced damage tolerance. They offer new understanding and design benchmarks for the development of engineered composites aiming to replicate nacre’s exceptional combination of toughness and recoverability.