Continuum Mechanical and Micromechanical Fundamentals of Mechanochemistry of Energetic Materials

含能材料机械化学的连续力学和微机械基础

• 批准号: 0201108
• 负责人: Valery Levitas
• 金额: $ 18万
• 依托单位: Texas Tech University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-08-01 至 2005-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0201108&HistoricalAwards=false
• 关键词: Continuum; Mechanical; Micromechanical; Fundamentals; Mechanochemistry

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.

含能材料机械化学的连续介质力学和微观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的可能点火源。 提出了一个为期三年的计划，以发展含能材料机械化学的连续力学和微观力学基础，新的分析和计算方法，并调查和系统化可能的新原因的剪切应力和应变引发的炸药。我们将集中讨论塑料粘结炸药（如PBX-9501），它由聚合物粘结剂连接的HMX高能晶体组成。本文的研究目标如下：1.发展一个系统的多尺度连续热力学，动力学和微观力学理论的应力和应变诱导的化学反应（CR）和相变（PT）在高能材料允许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。 将发展新的非弹性材料中CR和PT的解析和数值方法. 对不同应力张量下的微、中尺度PT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相基质内部的成核和生长; B）在升华过程中气相的成核和在HMX晶体内部或在与粘合剂的边界处的CR，以及在现有的和塌陷的空隙中; c）多级PT和CR。分析和数值研究剪切带中微观、细观和宏观尺度的反应诱导塑性和相变诱导塑性现象，以及它们对CR和PT热力学和动力学的影响（作为正机械化学反馈），以及对含能材料力学行为的影响（作为新的变形机制）.进行多尺度有限元建模和实验描述 关于炸药中剪切压力点火和初始后点火过程的研究。 研究了影响炸药剪切感度的材料参数和加载条件。