Description of anisotropy and chemo-mechanical interaction in porous materials

本研究涉及一类多孔材料的非弹性变形描述。重点放在两个基本问题上，即机械性能的各向异性和与化学-机械相互作用有关的退化现象。主要应用领域包括结构力学和地质力学。固有各向异性的主题将在宏观尺度上不均匀的材料的背景下讨论；特别是结构砌体和钢筋混凝土。研究将首先集中在砖砌体的非弹性变形的描述。将开发一个连续体公式，并将通过微观力学分析确定所涉及的材料功能。将宏观框架应用于魁北克北部水力发电设施关键砌体构件的地震稳定性评估。进一步的研究将在钢筋嵌入混凝土的力学响应建模领域进行。这里将再次采用微观/宏观力学的方法。这项研究将特别与核工业有关，特别是与评估受极端机械/热负荷影响的核密封结构的结构完整性有关。由于化学相互作用，许多天然材料和人造材料的机械性能都会显著下降。研究将主要集中在化学-力学耦合作用下的白垩变形特征建模。降解现象将归因于晶间压力溶解。这是一个发生在晶粒接触处的非平衡过程，包括通过间隙流体的扩散输送溶解和去除固体物质。制定总体宏观框架。均质化程序将被用来描述潜在的物理化学过程。这里的主要应用领域是石油工程。

This research is related to description of inelastic deformation in a class of porous materials. The emphasis is placed on two fundamental issues, i.e. that of anisotropy of mechanical properties and the degradation phenomena that are linked to chemo-mechanical interaction. The primary areas of application involve structural mechanics and geomechanics.    The topic of inherent anisotropy will be addressed in the context of materials that are heterogeneous on the macroscale; in particular, structural masonry and reinforced concrete. The research will focus first on the description of inelastic deformation of brick masonry. A continuum formulation will be developed and the material functions involved will be identified through a micromechanical analysis. The macroscopic framework will be applied to assess the seismic stability of critical masonry components of hydroelectric power generation facilities in Northern Quebec. Additional research will be conducted in the area of modeling of mechanical response of concrete with embedded sets of reinforcement. Here, again, a coupled micro/macro-mechanical approach will be pursued. The research will be particularly relevant to the nuclear industry, especially to the assessment of structural integrity of nuclear containment structures subjected to extreme mechanical/thermal loads.    A number of natural and manufactured materials undergo a significant degradation of mechanical properties as a result of chemical interaction. The research will focus mainly on modeling of deformation characteristics of chalk in the presence of chemo-mechanical coupling. The degradation phenomenon will be attributed to intergranular pressure solution. This is a non-equilibrium process that occurs at the grain contacts and consists of dissolution and removal of solid material by diffusive transport through the interstitial fluid. A general macroscopic framework will be developed. A homogenization procedure will be employed to describe the underlying physico-chemical processes. The primary area of application here is the petroleum engineering.