CAREER: Nonlinear Dynamics of Shear Wave Propagation and Shock Formation in Soft and Biological Materials

职业：软质和生物材料中剪切波传播和冲击形成的非线性动力学

• 批准号: 1942016
• 负责人: Tal Cohen
• 金额: $ 64.54万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-01 至 2025-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1942016&HistoricalAwards=false
• 关键词: CAREER; Nonlinear; Dynamics; Shear; Wave

This Faculty Early Career Development (CAREER) grant will focus on shear shock formation and propagation in soft materials. The advancement of fabrication techniques in recent years has spurred a rapid increase in the use of highly deformable materials in a myriad of engineering applications with examples ranging from wearable electronics, and soft robotics, to helmets, and seismic bearings. Dynamic loading of such soft structures can lead to a variety of material phenomena, which can generate significant damage. Protective gear should thus be capable of absorbing dynamic loads, such as impacts and blasts, which are now becoming appreciated as a major threat also to civilian lives in both mundane settings, such as sports, and as a result of more extreme events, such as exposure to improvised explosives. In these situations, both the protective material and the soft biological tissue may be subjected to extreme pressure gradients and impact. However, the basic mechanisms of damage and energy absorption are still poorly understood, thus hindering the maturation of new protective technologies that can mitigate damage in extreme environments. The integrated research and education plan will resolve deep mechanics questions regarding the shear shock formation criteria and level of energy dissipation and work to broaden participation in the engineering field. Recent experimental observations have suggested that the nonlinear evolution of ordinary shear waves into shear shocks could play a significant role in generating damage in soft and biological materials. However, while the vast amount of existing experimental and theoretical research on shock wave propagation in solids revolves around longitudinal shock mechanisms, the study of shear shock formation and propagation, from the point of view of large deformation solid mechanics is in nascent state, and the fundamental nature of these shock processes, the conditions required to form them, the resulting damage, and the level of energy dissipation, remain elusive. Hence, the interpretation of the reported observations is limited. This CAREER award aims to fill this void by employing a complementary combination of theoretical investigation and high-precision experimentation, through which it will illuminate the constitutive sensitivities of shear shock processes and the resulting mechanisms of damage. This fundamental understanding will then guide the design of more resilient material systems and can explain the vulnerability of specific biological organs.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.

这项教师早期职业发展（职业）格兰特将重点介绍软材料的剪切冲击形成和传播。 近年来，制造技术的进步刺激了在无数工程应用中使用高度变形材料的迅速增加，其范围从可穿戴电子设备和软机器人技术到头盔和地震轴承等等。这种软结构的动态载荷会导致各种物质现象，这会产生重大损害。因此，防护装备应能够吸收动态载荷，例如冲击和爆炸，现在在两种平凡的环境（例如运动）中也被视为对平民生活的主要威胁，以及由于更极端的事件，例如暴露于即兴爆炸物。在这些情况下，保护材料和软生物组织都可能受到极端压力梯度和影响。但是，损害和吸收能量的基本机制仍然很少了解，从而阻碍了新的保护技术的成熟，这些技术可以减轻极端环境中的损害。 综合研究和教育计划将解决有关剪切冲击形成标准和能量耗散水平的深刻力学问题，并致力于扩大对工程领域的参与。最近的实验观察结果表明，普通剪切波的非线性演变为剪切冲击可能在软化和生物材料中造成损害中起重要作用。然而，尽管固体中冲击波传播的大量现有实验和理论研究围绕纵向休克机制旋转，但从较大的变形固态的角度来看，剪切冲击形成和传播的研究是在新生状态的，以及这些冲击过程的基本性质，这些震动过程的基本性质，使得能量造成的损害，并造成了损害的层次。因此，对报告的观察结果的解释是有限的。该职业奖的目的是通过采用理论研究和高表演实验的互补组合来填补这一空白，通过该组合将阐明剪切冲击过程的本构敏感性和由此产生的损害机制。然后，这种基本的理解将指导更具弹性的材料系统的设计，并可以解释特定生物器官的脆弱性。该奖项反映了NSF的法定任务，并使用基金会的智力优点和更广泛的影响审查标准，被认为值得通过评估来支持。

项目成果

Nonlinear inclusion theory with application to the growth and morphogenesis of a confined body

非线性包含理论在约束体的生长和形态发生中的应用

• DOI: 10.1016/j.jmps.2021.104709
• 发表时间: 2022
• 期刊: Journal of the Mechanics and Physics of Solids
• 影响因子: 5.3
• 作者: Li, Jian;Kothari, Mrityunjay;Chockalingam, S.;Henzel, Thomas;Zhang, Qiuting;Li, Xuanhe;Yan, Jing;Cohen, Tal
• 通讯作者: Cohen, Tal

Morphogenesis and cell ordering in confined bacterial biofilms

受限细菌生物膜中的形态发生和细胞排序

• DOI: 10.1073/pnas.2107107118
• 发表时间: 2021
• 期刊: Proceedings of the National Academy of Sciences
• 作者: Zhang, Qiuting;Li, Jian;Nijjer, Japinder;Lu, Haoran;Kothari, Mrityunjay;Alert, Ricard;Cohen, Tal;Yan, Jing
• 通讯作者: Yan, Jing