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Background <p>Understanding the mechanical response and damage evolution of dynamic frictional interfaces is critical for optimizing tribological systems and uncovering the mechanisms behind impact and sliding.</p> Objective <p>This study presents a synchronized experimental approach with high spatiotemporal resolution to capture the transient thermomechanical response of mesoscopic asperities under impact loading. By directly correlating strain and temperature fields, the work reveals the damage mechanisms governing dynamic friction.</p> Methods <p>In this study, a synchronized experimental platform based on a Split Hopkinson Pressure Bar (SHPB) was established, integrating high-speed infrared thermography with visible imaging to capture the transient frictional behavior of Ti-6Al-4&#xa0;V and Al6061 pairs. A common signal generator simultaneously triggered high-speed visible and infrared cameras, ensuring image acquisition from symmetrical specimen regions. A U-Net based neural network was then implemented for cross-modal image registration, enabling the derivation of spatiotemporally aligned strain and thermal fields within a unified coordinate system.</p> Results <p>The synchronized measurements reveal distinct thermomechanical responses in Ti-6Al-4&#xa0;V and Al6061 asperity contacts. Ti-6Al-4&#xa0;V shows strong strain localization, rapid temperature rise, and shear fracture. In contrast, Al6061 exhibits more distributed plastic flow and lower thermal localization. These differences were quantified using peak shear strain, peak temperature, and the strain localization index. The single asperity numerical model reproduced the main experimental features, including the deformation mode, temperature distribution, and failure morphology. Based on the combined experimental and numerical results, a failure mechanism map was established to relate failure regimes to sliding velocity and contact geometry.</p> Conclusion <p>The method proposed in this study enables synchronized full-field characterization of transient strain and temperature evolution at asperity contacts. By combining high-speed multimodal imaging with U-Net based registration, the method captures the coupling between deformation localization, heat generation, and damage evolution. The results provide an experimental and numerical basis for identifying failure modes of rough interfaces under dynamic loading.</p>

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Simultaneous Characterization of Thermomechanical Evolution and Damage at Asperity Contacts Under Impact Loading

  • 期刊论文

  • 发表日期：

    2026年7月27日

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  • W. Liu,
  • X. Jia,
  • X. Liu,
  • H. Chen,
  • H. Yang

摘要

Background

Understanding the mechanical response and damage evolution of dynamic frictional interfaces is critical for optimizing tribological systems and uncovering the mechanisms behind impact and sliding.

Objective

This study presents a synchronized experimental approach with high spatiotemporal resolution to capture the transient thermomechanical response of mesoscopic asperities under impact loading. By directly correlating strain and temperature fields, the work reveals the damage mechanisms governing dynamic friction.

Methods

In this study, a synchronized experimental platform based on a Split Hopkinson Pressure Bar (SHPB) was established, integrating high-speed infrared thermography with visible imaging to capture the transient frictional behavior of Ti-6Al-4 V and Al6061 pairs. A common signal generator simultaneously triggered high-speed visible and infrared cameras, ensuring image acquisition from symmetrical specimen regions. A U-Net based neural network was then implemented for cross-modal image registration, enabling the derivation of spatiotemporally aligned strain and thermal fields within a unified coordinate system.

Results

The synchronized measurements reveal distinct thermomechanical responses in Ti-6Al-4 V and Al6061 asperity contacts. Ti-6Al-4 V shows strong strain localization, rapid temperature rise, and shear fracture. In contrast, Al6061 exhibits more distributed plastic flow and lower thermal localization. These differences were quantified using peak shear strain, peak temperature, and the strain localization index. The single asperity numerical model reproduced the main experimental features, including the deformation mode, temperature distribution, and failure morphology. Based on the combined experimental and numerical results, a failure mechanism map was established to relate failure regimes to sliding velocity and contact geometry.

Conclusion

The method proposed in this study enables synchronized full-field characterization of transient strain and temperature evolution at asperity contacts. By combining high-speed multimodal imaging with U-Net based registration, the method captures the coupling between deformation localization, heat generation, and damage evolution. The results provide an experimental and numerical basis for identifying failure modes of rough interfaces under dynamic loading.