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Mechanical behaviors and damage constitutive model of ceramics under shock compression

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Acta Mechanica Sinica 2008年第3期24卷 305-315页

作者： Jianguo Ning huilan ren Ping Li State Key Laboratory ot Explosion Science and Technology Beijing Institute of Technology 100081 Beijing China Laboratory for Shock Wave and Detonation Physics Research Institute of Fluid Physics CAEE 621900 Mianyang China

One-stage light gas gun was utilized to study the dynamic mechanical properties of AD90 alumina subjected to the shock loading. Manganin gauges were adopted to obtain the stress-time histories. The velocity interferometer system for any reflector （VISAR） was used to obtain the free surface velocity profile and determine the Hugoniot elastic limit. The Hugoniot curves were fitted with the experimental data. From Hugoniot curves the compressive behaviors of AD90 alumina were found to change typically from elastic to ＂plastic＂. The dynamic mechanical behaviors for alumina under impact loadings were analyzed by using the path line principle of Lagrange analysis, including the nonlinear characteristics, the strain rate dependence, the dispersion and declination of shock wave in the material. A damage model applicable to ceramics subjected to dynamic compressive loading has been developed. The model was based on the damage micromechanics and wing crack nucleation and growth. The effects of parameters of both the micro-cracks nucleation and the initial crack size on the dynamic fracture strength were discussed. The results of the dynamic damage evolution model were compared with the experimental results and a good agreement was found.

关键词： Mechanical behaviors Lagrange analysis Damage Tensile wing crack

Functional Morphology and Bending Characteristics of the Honeybee Forewing

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Journal of Bionic Engineering 2017年第1期14卷 111-118页

作者： Yun Ma huilan ren Jianguo Ning Pengfei Zhang State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology Beijing 100081 China

The present work aimed to reveal the functional morphology and bending characteristics of the worker honeybee （Apis mellifera） forewing. Honeybee wings including the forewing and hindwing, which are mainly composed of veins and membranes, are a kind of typical hierarchical biomaterials. We investigated the cross-sections of membranes, veins and wing hairs through Scanning Electron Microscopy （SEM）. Based on the microscopic observation, it was found that the vein is a thick-walled cylinder, and the membrane possesses multilayered structure and so does the wing hair which shows the thread surface. At the vein-membrane conjunctive position, membranes and veins are assembled seamlessly and veins are packed smoothly and tightly by membranes into a whole, allowing honeybees to perform excellent flapping flight. In such a case, we also conducted the cantilevered bending experiment of honeybee forewing to explore their bending characteristics using a MTS Tytron 250 micro force tester. Experiment results indicate that the anti-bending capacity of the forewing along the spanwise direction is higher than that along the chordwise direction which is partly caused by the wing corrugation along the wing span detected by the micro-Computed Tomography （micro-CT）, and ventral load bearing ability is better than dorsal one along the spanwise and chordwise direction of the wing which is due to the stress-stiffening of membranes. It could be concluded that the structural configuration of the wing is closely relevant to wing biomechanical behaviors. All results above would provide a significant support for the design of bioinspired wings for Flapping Micro Aerial Vehicles （FMAV）.

关键词： honeybee forewing functional morphology hierarchical structure bending stiffness

Numerical studies of penetration problems by an improved particle method

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Science China(Physics,Mechanics & Astronomy) 2012年第12期55卷 2273-2283页

作者： ren huilan MA TianBao YAO XiaoHu State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China Department of Engineering Mechanics School of Civil Engineering and TransportationSouth China University of TechnologyGuangzhou 510640China

A particle mapping transportation algorithm was proposed on the basis of the particle-in-cell *** particles with rectangular influence domains were employed in the transportation algorithm to reduce the numerical *** on the error analysis in the process of particle motion computation,a prediction-correction algorithm was introduced to improve the computational ***,the performance of the particle mapping transportation method was evaluated by using the rotation,the slotted disk and the shear advection tests,and the results were compared with other interface reconstruction ***,the hemispherical projectile penetration into a steel target was numerically *** results showed that the proposed method produced less numerical fluctuations and exhibited clear material interfaces,which indicated that it is accurate and effective.

关键词： numerical simulation particle-in-cell particle mapping transportation method interface tracking penetration

Failure behavior of cellular titanium under dynamic loading

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Science China(Technological Sciences) 2017年第4期60卷 613-623页

作者： ren huilan WANG Jing HAO Li SHEN HaiTing State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology School of Sciences Beijing University of Civil Engineering and Architecture

The dynamic compressive deformation of cellular titanium with regularly distributed cylindrical pores is investigated to evaluate the effect of shock attenuation and obtain the shock Hugoniot relationship of the material. Dynamic compression experiments are conducted at room temperature using a single-stage light gas gun. The Hugoniot relations between shock wave velocity and particle velocity for the cellular titanium samples with porosities 20% and 30% are obtained. The shock response of the regular cellular titanium shows a clear wave attenuation effect. Numerical simulations are also conducted to supplement the experimental *** deformation is observed in the samples using optical micrographs, indicating that the deformation of pores contributes significantly to the shock wave attenuation of the cellular titanium material.

关键词： plate impact cellular titanium Hugoniot relation dynamic compression

Empirical model of concrete block fragment behavior under explosion loads

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Science China(Technological Sciences) 2024年第8期67卷 2515-2529页

作者： YANG Shuai NING JianGuo ren huilan XU XiangZhao State Key Laboratory of Explosion Science and Safety Protection Beijing Institute of TechnologyBeijing 100081China

Concrete structures undergo integral fragmentation under explosion loads. The fragmentation degree and particle-size distribution of concrete blocks under explosion loads must be considered during mining to ensure safety. In this study, the impulse is calculated based on the relationship between overpressure and time, and the impact energy of the explosion wave is obtained based on blast theory. Subsequently, the Mohr-Coulomb shear strength fracture criterion is introduced to determine the ultimate shear stress of the concrete materials, and an empirical model that can effectively calculate the energy consumption of concrete blocks under explosion loads is established. Furthermore, concrete fragments with different particle sizes under explosion scenarios are quantitatively predicted with the principle of energy conservation. Finally, explosion tests with different top standoff distances are conducted, and the concrete fragments after the explosion tests are recovered, sieved, weighed, and counted to obtain experimental data. The effectiveness of the fragment empirical model is verified by comparing the model calculation results with the experimental data. The proposed model can be used as a reference for civil blasting, protective engineering design, and explosion-damage assessment.

关键词： concrete structures explosion loads fragment behavior empirical model

A constitutive model based on the evolution and coalescence of elliptical micro-cracks for quasi-brittle materials

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Chinese Science Bulletin 2012年第28期57卷 3773-3781页

作者： NING JianGuo ren huilan FANG MinJie State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology Beijing 100081 China

Damage and failure of quasi-brittle materials are caused by the evolution and coalescence of *** solve the problem of elliptical micro-crack growth at the elastic deformation stage,a method of complex potential functions is proposed and the effect of the initial orientation on micro-crack growth and deflection is *** critical stress condition for the initial damage is derived according to the criterion of micro-crack *** on energy conservation during wing-crack propagation,a damage constitutive model is developed with the strain criterion created in the condition of micro-crack *** stress-strain curves of quasi-brittle materials in uniaxial compression obtained based on this model are examined with the experimental results.

关键词：损伤本构模型准脆性材料微裂纹椭圆形合并基础演变裂纹生长

Additive Runge-Kutta methods for H_2/O_2/Ar detonation with a detailed elementary chemical reaction model

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Chinese Science Bulletin 2013年第11期58卷 1216-1227页

作者： LI Jian ren huilan NING JianGuo State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology

We report here the additive Runge-Kutta methods for computing reactive Euler equations with a stiff source term, and in particular, their applications in gaseous detonation simulations. The source term in gaseous detonation is stiff due to the presence of wide range of time scales during thermal-chemical non-equilibrium reactive processes and some of these time scales are much smaller than that of hydrodynamic flow. The high order, L-stable, additive Runge-Kutta methods proposed in this paper resolved the stiff source term into the stiff part and non-stiff part, in which the stiff part was solved implicitly while the non-stiff part was handled explicitly. The proposed method was successfully applied to simulating the gaseous detonation in a stoichiometric H2/O2 /Ar mixture based on a detailed elementary chemical reaction model comprised of 9 species and 19 elementary reactions. The results showed that the stiffly accurate additive Runge-Kutta methods can capture the discontinuity well, and describe the detonation complex wave configurations accurately such as the triple wave structure and cellular pattern.

关键词：化学反应模型添加剂塔引爆气相爆轰热化学非平衡应用程序时间尺度

A mass abrasion model with the melting and cutting mechanisms during high-speed projectile penetration into concrete slabs

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Acta Mechanica Sinica 2022年第10期38卷 14-27页

作者： Jianguo Ning huilan ren Zhao Li Xiangzhao Xu State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China China North Vehicle Research Institute Beijing100072China

In this study,ogive-nose projectile penetration into concrete slabs was tested at initial projectile impact velocities ranging from 1325.0 m/s to 1425.0 m/*** depth of penetration and mass loss of the projectiles were measured,and the residual projectiles were recovered after the penetration *** electron microscopy and metallographic microscopy of the microstructures were performed on various sections and outer surfaces of the projectiles taken from different locations of the residual projectiles,to analyze the intrinsic mechanisms of mass *** analysis results reveal that,during high-speed projectile penetration,projectile abrasion is caused by multiple *** on the cavity expansion theory,a projectile penetration model was established by considering the two main mass loss mechanisms observed in the microscopic *** theoretical predictions of the penetration depth,mass loss rate,and change of projectile head are consistent with the experimental results obtained both in this study and previous research.

关键词： Projectile abrasion Microscopic observation High-speed penetration Concrete target

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弹体贯穿混凝土数值模拟的改进材料模型

爆炸与冲击 2022年第11期42卷 77-89页

作者：任会兰荣誉许香照北京理工大学爆炸科学与技术国家重点实验室北京100081

研究混凝土结构在冲击载荷下的力学特性对武器以及防护结构的设计和评估具有重要意义,而合适的材料模型可以更准确地预测混凝土结构的力学行为和破坏模式。因此,本文中提出了一种改进的混凝土塑性损伤材料模型来描述其在冲击载荷下的力... 详细信息

研究混凝土结构在冲击载荷下的力学特性对武器以及防护结构的设计和评估具有重要意义,而合适的材料模型可以更准确地预测混凝土结构的力学行为和破坏模式。因此,本文中提出了一种改进的混凝土塑性损伤材料模型来描述其在冲击载荷下的力学响应。该改进模型考虑了压力-体积应变关系、应变率效应、洛德角效应和塑性损伤累积对混凝土材料力学特性的影响,并引入了一个与损伤相关的硬化/软化函数来描述压缩状态下的应变硬化和软化行为。随后,通过对3个独立的强度面进行线性插值得到了该改进模型的破坏强度面,并采用部分关联流动法则考虑了混凝土材料的体积膨胀特性。最后,开展了单个单元在不同加载条件下和弹体贯穿钢筋混凝土靶的数值模拟,验证了该改进模型的可行性、准确性以及预测性能提升。

关键词：混凝土冲击载荷材料模型硬化/软化函数塑性损伤累积

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