Microstructural Effects in Tayloring the Response of Engineered Bio-Materials

工程生物材料响应泰勒化中的微观结构效应

• 批准号: 1030673
• 负责人: Marek-Jerzy Pindera
• 金额: $ 22.97万
• 依托单位: University of Virginia Main Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2013-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1030673&HistoricalAwards=false
• 关键词: Microstructural; Effects; Tayloring; Response; Engineered

The goal of this research is to establish fundamental microstructure-property understanding needed for the development of a new generation of bio-engineered materials characterized by wavy microstructures, whose targeted performance is attained through micro-structural evolution based on the survival-of-the-fittest principles. Toughness, extensibility and adaptability may be realized through the exploitation of various arrangements of wavy microstructures, yet fundamental understanding of these architectural features vis-a-vis material response is lacking. Recent micro-structural simulation studies by the PI and co-workers demonstrated that layer thickness has a substantial impact on the homogenized response of periodic multi-layers with wavy microstructures in the inelastic domain. The proposed investigation addresses this recently discovered effect, and related effects, for the first time in engineered materials that mimic biological material response in the finite-deformation domain, including certain tissues. In particular, the investigation will answer the following questions, which have not been yet addressed, in the analysis and development of engineered materials with stiffening characteristics for bio-medical applications: (1) what is the effect of layer thickness on the homogenized and local responses of a wavy periodic multilayer in the finite-deformation domain?; (2) can targeted response of an engineered material with wavy microstructure be achieved using more than one microstructure?; (3) can connection between complexity and simplicity be established through an evolutionary design?The investigation employs a computational approach based on a novel homogenization technique called the parametric finite-volume direct averaging micromechanics (FVDAM) theory developed by the PI, his students and collaborators. This theory is particularly well suited for robust analysis, simulation and optimization of heterogeneous materials with accuracy comparable to the finite-element method, which presently is the computational standard, but with substantially greater efficiency. Experimentally measured response of three types of mitral valve chordea tendinea, which exhibit different levels of stiffening caused by different crimp patterns of the fibril bundles arranged in wavy layers, is employed in support of the verification and microstructural optimization component of the investigation.The intellectual merit stems both from the knowledge that will be generated and from further development of the theoretical tools necessary to accomplish it. Very little work based on first principles has been reported which is aimed at addressing the effect of microstructure in biological tissues on the overall response. The investigation will establish this connection for a particular material system that plays a significant role in biomedical applications. Further, the proposed theoretical enhancements of the parametric FVDAM theory will produce a paradigm shift in the theory's evolution, with the potential to replace the prevailing computational standard in the analysis and design of heterogeneous materials. The resulting computational technology will be readily employed in applications across several interdisciplinary boundaries, including traditional and emerging engineered materials with bio-inspired architectures. The theoretical enhancements involve the incorporation of finite-deformation capability into the FVDAM framework and the concomitant development of stable and accurate algorithms for the solution of structural mechanics problems in the finite-deformation domain, which continue to be a focus of the numerical engineering community. The proposed research is an important step in the parametric FVDAM theory?s continued development needed to realize its full potential across disciplinary boundaries. The broader impacts stem from the wide range of applications in which materials and structural components with wavy multilayer patterns are utilized across several scales and disciplines, ranging from corrugated structural panels to the rapidly developing nanotechnology areas. Microstructures with wavy architectures can potentially enhance certain performance characteristics such as stiffness, thermal stability and toughness. Yet, little systematic data is available addressing these issues in both the infinitesimal and finite-deformation domains. Moreover, the developed computational technology will be made available to the pertinent communities in the form of a Graphical User Interface to facilitate analysis, design and development of material systems for a wide range of applications, enabling material scientists and structural mechanicians alike to investigate what-if scenarios in pursuit of optimized and durable material microstructures. Concurrently, it will serve a greater educational purpose through training of both undergraduate and graduate students. Undergraduate students recruited from traditionally under-represented groups through the PI?s contact as an instructor in undergraduate courses, as well as through the well-known Center for Diversity at the University of Virginia, will be involved in the GUI?s testing and applications as summer interns who will further exploit this experience in their senior theses.

本研究的目标是建立开发以波状微结构为特征的新一代生物工程材料所需的基本微结构-性能理解，其目标性能是基于优胜劣汰原则通过微结构进化实现的。韧性、延展性和适应性可以通过开发各种波状微结构来实现，但对于这些结构特征与材料响应之间的关系缺乏基本的了解。PI和他的同事们最近的微结构模拟研究表明，层厚对非弹性区域内具有波状微结构的周期性多层膜的均匀响应有很大的影响。这项拟议的研究首次在工程材料中解决了最近发现的这种效应和相关效应，这种材料在有限变形领域模拟生物材料的反应，包括某些组织。特别是，这项研究将回答生物医学应用中具有刚性特性的工程材料的分析和开发中尚未解决的下列问题：(1)在有限变形域中，层厚度对波状周期性多层膜的均匀和局部响应有什么影响？(2)具有波状微结构的工程材料是否可以使用多个微结构来实现目标响应？(3)是否可以通过进化设计在复杂性和简单性之间建立联系？本研究采用了一种基于参数有限体积直接平均细观力学(FVDAM)理论的计算方法，该理论是由PI及其学生和合作者开发的。这一理论特别适合于非均质材料的稳健分析、模拟和优化，其精度与有限元方法相当，有限元方法目前是计算标准，但效率要高得多。实验测量了三种类型的二尖瓣索肌腱的反应，它们显示出不同程度的僵硬，这是由于排列成波浪层的纤维束的不同卷曲模式所致，用于支持研究的验证和微观结构优化部分。智力优势来自将产生的知识和完成该研究所需的理论工具的进一步发展。很少有基于第一性原理的工作被报道，这些工作的目的是解决生物组织中微结构对整体反应的影响。这项研究将为在生物医学应用中发挥重要作用的特定材料系统建立这种联系。此外，参数FVDAM理论的拟议理论增强将在该理论的发展过程中产生范式转换，有可能取代非均质材料分析和设计中的主流计算标准。由此产生的计算技术将容易地应用于跨越几个跨学科边界的应用，包括具有生物灵感结构的传统和新兴工程材料。理论上的改进包括将有限变形能力纳入FVDAM框架，以及相应地开发稳定和准确的算法来解决有限变形领域的结构力学问题，这仍然是数值工程界的一个焦点。提出的研究是参数FVDAM理论的重要一步？S需要继续发展，以实现其跨学科边界的全部潜力。更广泛的影响源于广泛的应用，在这些应用中，具有波浪形多层图案的材料和结构部件被用于几个规模和学科，从波纹结构板到快速发展的纳米技术领域。具有波浪形结构的微结构可以潜在地提高某些性能特性，如刚性、热稳定性和韧性。然而，在无限小和有限变形领域，几乎没有系统的数据来解决这些问题。此外，开发的计算技术将以图形用户界面的形式提供给相关社区，以促进广泛应用的材料系统的分析、设计和开发，使材料科学家和结构机械师能够研究假设情景，追求优化和耐用的材料微结构。同时，它将通过培养本科生和研究生来服务于更大的教育目的。从传统上代表性不足的群体中招募的本科生，通过派？S联系人作为本科课程的讲师，以及通过著名的弗吉尼亚大学多样性中心，将作为暑期实习生参与图形用户界面？S的测试和应用，他们将在高级论文中进一步利用这一经验。