CAREER: Fracture Mechanics of Soft Dissipative Materials

职业：软耗散材料的断裂力学

• 批准号: 1752449
• 负责人: Rong Long
• 金额: $ 50万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-05-01 至 2024-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1752449&HistoricalAwards=false
• 关键词: CAREER; Fracture; Mechanics; Soft; Dissipative

This Faculty Early Career Development Program (CAREER) award will support fundamental research on the fracture resistance of soft elastomers and hydrogels. Soft materials that can undergo large reversible deformation have been widely utilized in industrial applications such as tires and soft adhesives, or emerging technologies such as soft robots, biomedical implants and stretchable display. In these applications, the underlying soft materials are required to be stretchable to enable functionality and yet fracture resistant to enhance reliability. Driven by this need, various physical or chemical mechanisms have been developed to enhance the fracture resistance of soft materials, and they share a common theme: to introduce energy dissipation or consumption by the material during deformation. However, theoretical modeling and experimental characterization of fracture in such soft dissipative materials are challenging due to the lack of understandings on the quantitative relation between energy dissipation and fracture resistance. This research program will establish experimental and modeling capabilities to uncover the complex nonlinear mechanics associated with soft material fracture, which will lead to quantitative principles for engineering new soft functional materials that are mechanically robust, as well as new tools to measure and predict fracture in soft materials. Thus, the research will promote the science of soft material fracture to advance the national health, prosperity, and welfare. As part of research, education and outreach programs will be developed to promote research of soft material fracture in academic, educational and industrial sectors by creating an interdisciplinary summer workshop, integrating research findings into curriculum and K-12 outreach activities, and building collaborations with industrial partners.A major challenge in soft material fracture is the large deformation near the tip of a crack, which causes nonlinear strain and stress fields as well as complex failure and dissipation behaviors. To address this challenge, a particle tracking method will be used to measure the crack tip deformation field in model soft materials under various fracture modes. For elastic materials, the experiments will provide data to assess the region of validity for existing crack tip asymptotic solutions, to discover new structures of crack tip fields, and to enable local evaluation of energy release rate through the J-integral, thus eliminating the requirement of specialized experimental geometries. For dissipative materials, the experimental data of crack tip deformation field, augmented by accurate constitutive models, will be used to identify the crack tip dissipation zone and to separately measure the intrinsic and dissipative toughness. A finite element model will also be developed to couple the crack tip failure process, represented by a cohesive zone, with the bulk material dissipation, which will enable the prediction of crack growth in soft dissipative materials.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该学院早期职业发展计划（CAREER）奖将支持软弹性体和水凝胶抗断裂性的基础研究。可发生较大可逆变形的软材料已广泛应用于轮胎和软粘合剂等工业应用，或软机器人、生物医学植入物和可拉伸显示器等新兴技术中。在这些应用中，底层软材料需要具有可拉伸性以实现功能性，同时又需要具有抗断裂性以提高可靠性。在这种需求的驱动下，人们开发了各种物理或化学机制来增强软材料的抗断裂能力，它们有一个共同的主题：在变形过程中引入材料的能量耗散或消耗。然而，由于缺乏对能量耗散和断裂抗力之间的定量关系的理解，这种软耗散材料的断裂理论建模和实验表征具有挑战性。该研究项目将建立实验和建模能力，以揭示与软材料断裂相关的复杂非线性力学，这将为工程机械坚固的新型软功能材料提供定量原理，以及测量和预测软材料断裂的新工具。因此，这项研究将促进软材料断裂科学的发展，以促进国民的健康、繁荣和福利。作为研究、教育和推广计划的一部分，将制定跨学科夏季研讨会，将研究成果纳入课程和 K-12 推广活动，以及与工业合作伙伴建立合作，以促进学术、教育和工业部门对软材料断裂的研究。软材料断裂的一个主要挑战是裂纹尖端附近的大变形，这会导致非线性应变和应力场以及复杂的失效和耗散 行为。为了应对这一挑战，将使用粒子跟踪方法来测量模型软材料在各种断裂模式下的裂纹尖端变形场。对于弹性材料，实验将提供数据来评估现有裂纹尖端渐近解的有效区域，发现裂纹尖端场的新结构，并通过 J 积分对能量释放率进行局部评估，从而消除对专门实验几何形状的要求。对于耗散材料，裂纹尖端变形场的实验数据通过精确的本构模型增强，将用于识别裂纹尖端耗散区并分别测量固有韧性和耗散韧性。还将开发一个有限元模型，将裂纹尖端失效过程（以粘性区为代表）与散装材料耗散耦合起来，这将能够预测软耗散材料中的裂纹扩展。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Mixed-mode fracture in a soft elastomer

• DOI: 10.1016/j.eml.2021.101380
• 发表时间: 2021-10
• 期刊: Extreme Mechanics Letters
• 影响因子: 4.7
• 作者: Yinan Lu;Yuan Qi-;Michely Tenardi;Rong Long

Steady state crack growth in viscoelastic solids: A comparative study

• DOI: 10.1016/j.jmps.2021.104748
• 发表时间: 2022-01-03
• 期刊: JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
• 影响因子: 5.3
• 作者: Hui, Chung-Yuen;Zhu, Bangguo;Long, Rong
• 通讯作者: Long, Rong

Understanding the friction and deformation behavior of micro/nano-hierarchical textures through in-situ SEM observation and mechanics modeling

• DOI: 10.1016/j.triboint.2021.107271
• 发表时间: 2021-09-20
• 期刊: TRIBOLOGY INTERNATIONAL
• 影响因子: 6.2
• 作者: Afshar-Mohajer, Mahyar;Yang, Xingwei;Zou, Min
• 通讯作者: Zou, Min

Enhancing the toughness of composites via dynamic thiol–thioester exchange (TTE) at the resin–filler interface

• DOI: 10.1039/d0py00563k
• 发表时间: 2020-07
• 期刊: Polymer Chemistry
• 影响因子: 4.6
• 作者: Nancy Sowan;Yinan Lu;Kevin J. Kolb;L. Cox;Rong Long;C. Bowman

Stimulation Modulates Adhesion and Mechanics of Hydrogel Adhesives

刺激调节水凝胶粘合剂的粘合力和力学

• DOI: 10.1021/acs.langmuir.1c00696
• 发表时间: 2021
• 期刊: Langmuir
• 影响因子: 3.9
• 作者: Yang, Zhen;Yang, Xingwei;Long, Rong;Li, Jianyu
• 通讯作者: Li, Jianyu