Continuum Mechanical and Micromechanical Fundamentals of Mechanochemistry of Energetic Materials

含能材料力学化学的连续力学和微力学基础剪切应力和剪切带被许多研究者认为是含能材料和炸药可能的引燃源。提出了一项为期三年的计划，以发展含能材料力学化学的连续力学和微力学基础，新的分析和计算方法，并研究和系统地研究炸药剪应力和应变引发的可能的新原因。我们将集中讨论塑料粘结炸药（例如PBX-9501），它由聚合物粘结剂连接的HMX高能晶体组成。本文提出的研究目标如下：1。为含能材料中应力和应变诱导的化学反应（CR）和相变（PT）建立系统的多尺度连续热力学、动力学和微观力学理论，允许CR、剪切应力和大塑性应变、温度和压力之间的热力学和动力学耦合。发展非弹性材料中CR和PT的新的解析和数值方法。对不同应力张量下的微尺度和中尺度ptr和CR模拟中的一些典型问题进行了解析和数值研究。这些问题包括：a) d相在b相基体内部形核长大；b)升华过程中气相的成核，HMX晶体内部或与粘结剂交界处的CR，以及存在和坍缩的空隙；c)多级PT和cr。3 .研究微观、中观和宏观剪切带中反应诱导塑性和转变诱导塑性现象，以及它们对CR和PT的热力学和动力学（作为正力学化学反馈）的影响，以及对含能材料的力学行为（作为新的变形机制）的影响。对炸药剪切压点火和初始后点火过程进行多尺度有限元建模和实验描述。找出影响炸药剪切敏感性的材料参数和加载条件。

Continuum Mechanical and Micromechanical Fundamentals ofMechanochemistry of Energetic MaterialsShear stress and shear banding are suggested by many investigators as possible sources of ignition in energetic materials and explosives. A three-year program is proposed to develop continuum mechanical and micromechanical fundamentals of mechanochemistry of energetic materials, new analytical and computational methods, and to investigate and systematize possible new reasons for shear stress and strain initiation of explosives. We will concentrate on plastic bonded explosives (e.g. PBX-9501) which consist of HMX energetic crystals connected by a polymer binder. The objectives of the research proposed are as follows:1. To develop a systematic multiscale continuum thermodynamic, kinetic and micromechanical theory for stress- and strain-induced chemical reactions (CR) and phase transformations (PT) in energetic materials allowing for thermodynamic and kineticcoupling between CR, shear stress and large plastic strains, temperature and pressure. New analytical and numerical methods for CR and PT in inelastic materials will be developed.2. To study analytically and numerically some typical problems for modeling of PTand CR at the microscale and mesoscale under various prescribed stress tensors. These problems include: a) Nucleation and growth of the d phase inside of the b phase matrix; b) Nucleation of the gas phase during sublimation and CR inside the HMX crystal or at the boundary with the binder, as well as in existing and collapsing voids; c) Multistage PT and CR.3. To investigate analytically and numerically reaction-induced plasticity and transformation-induced plasticity phenomena in the shear band at micro-, meso-, and macroscales, and their effect on the thermodynamics and kinetics of CR and PT (as positivemechanochemical feedback), as well as on the mechanical behavior of energetic materials (as the new deformation mechanism).4. To conduct multiscale finite element modeling and description of experiments on combined shear-pressure ignition and initial post-ignition processes in explosives. Material parameters and loading conditions responsible for shear sensitivity of explosives will be found.