Effects of Heating-Induced Phase Transition on Damage for HMX Crystal
-
摘要: HMX基PBX炸药混合体系中炸药晶体在发生高温熔化和分解反应之前,会率先发生非均匀热膨胀和固相晶型转变,使材料的力学性能和安全性能发生突变。为探究HMX晶体的热致相变对材料内部损伤演化的影响机制,发展了考虑HMX晶体热膨胀和相变等变形机制的热力耦合晶体本构模型,从力学角度揭示了黏结剂包覆HMX晶体相变对体积变形、应力状态以及裂纹成核演化过程的影响机理,量化分析了升温速率对材料相变和裂纹损伤状态的影响规律。结果表明:随着加载温度升高,HMX晶体的热膨胀和
$\,\beta $ →$\delta $ 相变导致体积增大,晶体内部形成拉伸应力状态,同时晶体与黏结剂相互挤压形成的局部压剪作用使晶体内部出现裂纹成核和扩展现象。相变温度附近HMX晶体内部裂纹成核和扩展数量显著增加,晶体内部发生不可逆损伤。外界升温速率对晶体内部裂纹形核扩展与损伤造成显著影响,较高的升温速率会加大晶体损伤程度,增加炸药内潜在热点源及意外点火风险。Abstract: At high temperature loading, the thermal expansion and solid-solid phase transition firstly occur in HMX-based PBXs prior to the melting and decomposition of HMX crystal, thereby inducing the abrupt change of mechanical and safety properties. A constitutive model integrating with several deformation mechanisms, including thermal expansion, and phase transition was developed to investigate the effects of heating-induced phase transition on damage evolution. The influence mechanisms of phase transition in binder-bonded HMX single crystal on the volumetric deformation, stress states and crack nucleation and growth were revealed from the viewpoint of mechanics. The effects of heating rate on phase transition and crack related damage evolution were quantitatively analyzed. The calculated results show that, as the increase of loading temperature, tension stress formed due to the thermal expansion and$\,\beta $ →$\delta $ phase transition in unilateral-restrained HMX crystal and local shear stress formed due to mutually compression between crystal and binder, contribute to the nucleation and growth of HMX crystal. The number density of cracks exhibits a remarkable growth near the phase transition temperature, thereby inducing the irreversible damage. The heating rate has a significant influence on the nucleation and growth of cracks. Large heating rate will increase the crack related damage level of crystal, thereby increasing the number density of potential hotspots and risks of inadvertent ignition.-
Key words:
- HMX single crystal /
- heating-induced phase transition /
- thermal expansion /
- crack growth /
- damage
-
表 1
$\,\beta $ -HMX的弹性常数及其温度系数Table 1. Elastic constants and temperature coefficients of
$\,\beta $ -HMXC11/GPa C12/GPa C13/GPa C15/GPa C22/GPa C23/GPa C25/GPa 22.2 9.6 13.2 −0.1 23.9 13.0 4.7 C33/GPa C44/GPa C55/GPa C66/GPa C35/GPa C46/GPa $\dfrac{ {{\rm d}{C{_{11} } } } }{ {{\rm d}T} }$/(GPa·K−1) 23.4 9.2 11.1 10.1 1.6 2.5 −0.030 $\dfrac{ {{\rm d}{C{_{12}} } } }{ {{\rm d}T} }$/(GPa·K−1) $\dfrac{ {{\rm d}{C{_{13}} } } }{ {{\rm d}T} }$/(GPa·K−1) $\dfrac{ {{\rm d}{C{{_{15}} } } } }{ {{\rm d}T} }$/(GPa·K−1) $\dfrac{ {{\rm d}{C{_{22}} } } }{ {{\rm d}T} }$/(GPa·K−1) $\dfrac{ {{\rm d}{C{_{23}} } } }{ {{\rm d}T} }$/(GPa·K−1) $\dfrac{ {{\rm d}{C{_{25}} } } }{ {{\rm d}T} }$/(GPa·K−1) $\dfrac{ {{\rm d}{C{_{33}} } } }{ {{\rm d}T} }$/(GPa·K−1) −0.001 −0.012 0.002 −0.023 −0.018 0.005 −0.003 $\dfrac{ {{\rm d}{C{_{44}} } } }{ {{\rm d}T} }$/(GPa·K−1) $\dfrac{ {{\rm d}{C{_{55}} } } }{ {{\rm d}T} }$/(GPa·K−1) $\dfrac{ {{\rm d}{C{_{66}} } } }{ {{\rm d}T} }$/(GPa·K−1) $\dfrac{ {{\rm d}{C{_{35}} } } }{ {{\rm d}T} }$/(GPa·K−1) $\dfrac{ {{\rm d}{C{_{46}} } } }{ {{\rm d}T} }$/(GPa·K−1) −0.009 −0.004 −0.007 0.003 0.004 表 2
$\delta $ -HMX的弹性常数及其温度系数Table 2. Elastic constants and temperature coefficients of
$\delta $ -HMXC11/GPa C12/GPa C13/GPa C22/GPa C23/GPa C33/GPa 14.5 10.6 10.3 14.0 10.3 18.0 C44/GPa C55/GPa C66/GPa $\dfrac{ {{\rm d}{C{_{11} }} } }{ {{\rm d}T} }$/(GPa·K−1) $\dfrac{ {{\rm d}{C{_{12}} } } }{ {{\rm d}T} }$/(GPa·K−1) $\dfrac{ {{\rm d}{C{_{13}} } } }{ {{\rm d}T} }$/(GPa·K−1) 4.4 4.4 2.3 −0.014 −0.007 −0.009 $\dfrac{ {{\rm d}{C{_{22} }} } }{ {{\rm d}T} }$/(GPa·K−1) $\dfrac{ {{\rm d}{C{_{23}} } } }{ {{\rm d}T} }$/(GPa·K−1) $\dfrac{ {{\rm d}{C{_{33} }} } }{ {{\rm d}T} }$/(GPa·K−1) $\dfrac{ {{\rm d}{C{_{44}} } } }{ {{\rm d}T} }$/(GPa·K−1) $\dfrac{ {{\rm d}{C{_{55}} } } }{ {{\rm d}T} }$/(GPa·K−1) $\dfrac{ {{\rm d}{C{_{66}} } } }{ {{\rm d}T} }$/(GPa·K−1) −0.014 −0.009 −0.019 −0.006 −0.006 −0.007 表 3 HMX单晶模型的物理参数
Table 3. Physical parameters for HMX single crystal model
Phase $\,\rho $/(kg∙m−3) cV/(J∙kg−1∙K−1) α11/K−1 α22/K−1 α33/K−1 α13/K−1 $\,\beta $ 1900 667 −2.90×10−6 1.16×10−4 1.79×10−5 −1.26×10−5 $\delta $ 1760 667 6.18×10−5 6.18×10−5 2.47×10−5 表 4 HMX的
$\,\beta $ →$\delta $ 相变模型参数Table 4. Parameters related to
$\,\beta $ →$\delta $ phase transition model of HMXi Q/(m3∙mol−1) S*/(J∙mol−1∙K−1) H*/(kJ∙mol−1) V*/(10−5 m3∙mol−1) 1 1.00 144.44 207.691 1.14 −1 1.00 121.68 197.891 0 2 3.0×10−10 149.85 79.700 2.33 −2 3.0×10−10 127.09 69.900 1.19 表 5 界面与HMX晶体内双线性内聚力模型参数
Table 5. Bilinear cohesive model parameters for interface and HMX granular
Position K11/(MPa∙m−1) K22/(MPa∙m−1) K33/(MPa∙m−1) T11/MPa T22/MPa T33/MPa G/(J∙m−2) Interface 1.556 1.556 1.556 1.66 1.66 1.66 80.0 Intra-HMX 106 106 106 2.0 3.0 3.0 100.0 -
[1] ASAY B W. Non-shock initiation of explosives [M]. New York: Springer, 2010. [2] DAI X G, WEN Y S, WEN M P, et al. Projectile impact ignition and reaction violent mechanism for HMX-based polymer bonded explosives at high temperature [J]. Propellants, Explosives, Pyrotechnics, 2017, 42(7): 799–808. doi: 10.1002/prep.201600130 [3] 文玉史, 文雯, 代晓淦, 等. 相变与微裂纹对HMX晶体高温下撞击感度的影响机制 [J]. 含能材料, 2019, 27(3): 184–189. doi: 10.11943/CJEM2018116WEN Y S, WEN W, DAI X G, et al. Influence mechanism of phase transition and micro cracks on impact sensitivity of HMX crystal at high temperature [J]. Chinese Journal of Energetic Materials, 2019, 27(3): 184–189. doi: 10.11943/CJEM2018116 [4] 郜婵, 孙晓宇, 梁文韬, 等. RDX, HMX及CL-20晶体的高温高压相变研究进展 [J]. 含能材料, 2020, 28(9): 902–914. doi: 10.11943/CJEM2020088GAO C, SUN X Y, LIANG W T, et al. Review on phase transition of RDX, HMX and CL-20 crystals under high temperature and high pressure [J]. Chinese Journal of Energetic Materials, 2020, 28(9): 902–914. doi: 10.11943/CJEM2020088 [5] HENSON B F, ASAY B W, SANDER R K, et al. Dynamic measurement of the HMX β-δ phase transition by second harmonic generation [J]. Physical Review Letters, 1999, 82(6): 1213–1216. doi: 10.1103/PhysRevLett.82.1213 [6] HU W J, WU Y Q, HUANG F L, et al. Numerical simulation analyses of β↔δ phase transition for a finite-sized HMX single crystal subjected to thermal loading [J]. RSC Advances, 2018, 8(44): 24873–24882. doi: 10.1039/C8RA02649A [7] WANG X J, WU Y Q, HU W J, et al. Anisotropic mechanical-thermal-phase transformation response of cyclotetramethylene tetranitramine (HMX) single crystal under ramp loading [J]. International Journal of Solids and Structures, 2020, 200: 170–187. doi: 10.1016/j.ijsolstr.2020.05.024 [8] 胡惟佳. 高温下炸药晶体尺度相变效应及损伤点火响应研究 [D]. 北京: 北京理工大学, 2020.HU W J. Phase transition and damage ignition response of explosives under high temperature at the crystal scale [D]. Beijing: Beijing Institute of Technology, 2020. [9] XUE C, SUN J, KANG B, et al. The β-δ phase transition and thermal expansion of octahydro-1, 3, 5, 7-tetranitro-1, 3, 5, 7-tetrazocine [J]. Propellants, Explosives, Pyrotechnics, 2010, 35(4): 333–338. doi: 10.1002/prep.200900036 [10] WILLEY T M, LAUDERBACH L, GAGLIARDI F, et al. Mesoscale evolution of voids and microstructural changes in HMX-based explosives during heating through the β-δ phase transition [J]. Journal of Applied Physics, 2015, 118(5): 055901. doi: 10.1063/1.4927614 [11] 代晓淦. 高温下HMX基PBX炸药撞击响应规律及影响机制研究 [D]. 北京: 北京理工大学, 2018.DAI X G. Impact responses and influence mechanisms of HMX-based polymer-bonded explosives subjected to elevated temperature [D]. Beijing: Beijing Institute of Technology, 2018. [12] HENSON B F, SMILOWITZ L, ASAY B W, et al. The β–δ phase transition in the energetic nitramine octahydro-1, 3, 5, 7-tetranitro-1, 3, 5, 7-tetrazocine: thermodynamics [J]. The Journal of Chemical Physics, 2002, 117(8): 3780–3788. doi: 10.1063/1.1495398 [13] 范正杰, 刘占芳. 升温和降温引起TATB基PBX炸药脱黏的数值分析 [J]. 应用数学和力学, 2020, 41(9): 956–973. doi: 10.21656/1000-0887.410062FAN Z J, LIU Z F. Numerical analysis on debonding of crystal-binder interface in TATB-based polymer-bonded explosive caused by heating and cooling processes [J]. Applied Mathematics and Mechanics, 2020, 41(9): 956–973. doi: 10.21656/1000-0887.410062 [14] TAN H, LIU C, HUANG Y, et al. The cohesive law for the particle/matrix interfaces in high explosives [J]. Journal of the Mechanics and Physics of Solids, 2005, 53(8): 1892–1917. doi: 10.1016/j.jmps.2005.01.009. [15] XIA Q Z, WU Y Q, HUANG F L. Effect of interface behaviour on damage and instability of PBX under combined tension–shear loading [J]. Defence Technology, 2022.