From assembly to mechanics: predictive scale bridging simulations of spider silk

从装配到机械：蜘蛛丝的预测尺度桥接模拟

• 批准号: 206924251
• 负责人: Professorin Dr. Frauke Gräter
• 金额: --
• 依托单位: Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2011
• 资助国家: 德国
• 起止时间: 2010-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/206924251?language=en
• 关键词: assembly; mechanics; predictive; scale; bridging

Biomaterials can feature superior toughness compared to synthetic materials, which is thought to hinge upon the underlying nano-scale structure. Silk is one such protein-based nano-structured biomaterials. We have previously, during the first funding period of this DFG Sachbeihilfe, addressed the interplay between the beta-sheet protein crystals and the surrounding disordered protein chains in silk. To study these systems, we have employed Molecular Dynamics (MD) simulations at the nano-scale to derive parameters, which were fed into larger material-scale models solved with finite element analysis (FEA). In these previous studies, the established fiber model showed very good agreement with experimental data with regard to its mechanical characteristics. More importantly, we observed an unexpected phenomenon, namely a stretch-induced increase in order of crystalline regions along the fiber axis, which now - excitingly - was confirmed by small angle neutron scattering experiments of our collaborators.In the next funding period, we propose to improve our understanding of silk mechanics along these lines. We will systematically assess the determinants of the mechanical properties of silk, including strength, toughness, friction, and self-ordering. To this end, we will employ and further refine our multi-scale bottom-up simulation approach as developed in our first funding period. Importantly, as the major novelty of this proposal, we will not anymore assume a certain structural preposition for the MD and FEA, but instead will go one step back and thoroughly address the question of structure formation as it occurs under shear flow, again following a new multiscale bottom-up approach. We expect the work program to represent a leap forward in understanding and redesigning the intricate coupling between assembly, structure, and mechanics of nanoscale biomaterials.

与合成材料相比，生物材料可以具有上级韧性，这被认为取决于底层的纳米级结构。蚕丝就是这样一种基于蛋白质的纳米结构生物材料。我们以前，在DFG Sachbeihilfe的第一个资助期内，解决了β折叠蛋白质晶体与丝绸中周围无序蛋白质链之间的相互作用。为了研究这些系统，我们采用了纳米尺度的分子动力学（MD）模拟来获得参数，这些参数被馈送到用有限元分析（FEA）求解的更大的材料尺度模型中。在这些先前的研究中，所建立的纤维模型显示出非常好的协议与实验数据方面的机械特性。更重要的是，我们观察到了一个意想不到的现象，即拉伸诱导的结晶区域沿沿着纤维轴的顺序增加，现在-令人兴奋的是-我们的合作者的小角中子散射实验证实了这一点。在下一个资助期，我们建议沿着这些路线提高我们对丝力学的理解沿着。我们将系统地评估丝的机械性能的决定因素，包括强度，韧性，摩擦和自排序。为此，我们将采用并进一步完善我们在第一个资助期开发的多尺度自下而上的模拟方法。重要的是，作为该提案的主要新奇，我们将不再为MD和FEA假设某种结构介词，而是后退一步，彻底解决剪切流下发生的结构形成问题，再次遵循新的多尺度自底向上方法。我们希望这项工作计划代表了理解和重新设计纳米级生物材料的组装，结构和力学之间复杂耦合的飞跃。