共查询到17条相似文献,搜索用时 468 毫秒
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橡胶材料的动态压缩性能及其应变率相关的本构模型 总被引:3,自引:0,他引:3
利用Instron万能试验机与LC4超硬铝合金分离式Hopkinson压杆设备,对3种不同波阻抗的橡胶材料——炭黑母胶(Carbon Black Rubber)、硅橡胶(Silicone Rubber)和泡沫橡胶(Foam Rubber)在较大应变率范围(0.002~15 000s-1)内进行了单轴压缩实验,研究应变率对橡胶材料力学性能的影响。实验结果表明:3种橡胶的准静态与动态应力-应变曲线具有不同的应变硬化形式,且动态加载下随着应变率的增大,硬化效应逐渐增强;在准静态及高应变率(12 000~15 000 s-1)压缩下,泡沫橡胶表现出多孔类材料压缩曲线的弹性、塑性崩塌及致密化3段特征。基于Rivilin应变能模型,构建了一个应变率相关的动态本构模型,模拟结果与实验结果吻合较好,可以用于描述较大应变率范围内3种橡胶的非线性应力-应变关系。 相似文献
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研究了固体炸药PBX代用材料D-90031的微观结构、压制过程中产生的原生缺陷形态,以及动态力学行为和破坏特征。采用数字图像分析技术、纳米力学测试系统,以及分离式霍普金森压杆(SHPB)实验和落锤冲击技术,获得了微观结构特点、各组分的硬度和弹性模量、动态性能,以及碎片的尺寸分布规律和材料的破坏形式。研究发现,晶粒的形态随外载的作用而改变,晶粒沿垂直加载方向伸长,材料的碎块尺寸满足一定的规律。研究结果对于深入认识固体炸药的性能与微观结构的关系具有一定的指导意义。 相似文献
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《高压物理学报》2017,(1)
5083铝合金材料在工程领域应用广泛,会受到包括冲击和碰撞等多种不同情况的强动加载,亟需对其宽应变率加载下的力学性能及其本构模型开展研究。首先,对5083铝合金进行了系统的准静态实验及中、高应变率加载下的拉伸和压缩实验,得到了宽应变率加载下的应力-应变曲线。实验结果表明,该材料在同一实验条件下所得到的应力-应变曲线,其强化阶段的拉伸曲线总是低于压缩曲线,并从微观机制上对这一现象进行了合理解释。然后,通过引入损伤,考虑了损伤对该材料拉伸加载情况下的力学性能影响。基于连续介质力学及其实验结果,获得了损伤演化方程。最后,借助改进的Johnson-Cook(JC)本构模型,并基于已确定的损伤演化方程,得到了考虑损伤的5083铝合金本构模型。通过实验曲线与所得模型曲线的对比,吻合良好,表明该模拟具有很好的适用性,能够对该材料的工程应用提供有效的科学依据、分析模型和必要的参考。 相似文献
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采用半圆盘弯曲实验和数字散斑相关方法,对高聚物粘结炸药(PBX)的宏、细观断裂行为进行了实验研究。宏观上,带有预制裂纹的半圆盘试样发生拉伸破坏,利用数字散斑相关技术得到了试样的应变场和位移矢量场分布,定量分析了试样全场的变形特征,并测得了PBX材料的平面应变断裂韧性;细观上,用配有加载装置的扫描电子显微镜对含预制裂纹的半圆盘试样间接拉伸下的损伤演化和破坏过程进行了实时原位观察,借助于数字散斑相关方法,定量分析了试样损伤局部化特征。结果表明,将数字散斑相关方法用于研究PBX材料宏、细观尺度上的变形破坏问题是有效的。 相似文献
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报导了由短脉冲激光引起的应力波加载及电炮驱动Mylar膜平面飞片碰撞TC4、TC9钛合金靶的实验及数值计算研究结果。由回收靶样品的金相分析表明:在电炮驱动飞片碰撞及由激光引起的应力波加载所造成的应变率分别在106 s-1左右及107 s-1以上两种情形下,TC4、TC9钛合金的层裂特性都是以微孔洞的成核、增长、汇合为特征的韧性断裂。运用一维流体弹塑性动力学程序进行数值研究表明:成核增长NAG模型在一定程度上可以用来描述高应变率下TC4、TC9钛合金的损伤破坏特性。 相似文献
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Dynamic Tensile Behavior and Fracture Mechanism of Polymer Composites Embedded with Tetraneedle-Shaped ZnO Nanowhiskers 下载免费PDF全文
Dynamic tensile properties of glass-fiber polymer composites embedded with ZnO nanowhiskers are investigated by a split Hopkinson tensile bar. The stress-strain curves, ultimate strength, failure strain and elastic modulus are obtained and the failure mechanism of the composites is investigated by the macroscopic and microscopic observation of fractured specimens. The strain rate effect on the mechanical behavior is discussed and a constitutive model is derived by simulating the experimental data. The experimental results show that the materials have an obvious non-linear constitutive relation and strain rate strengthening effect. The composites with ZnO nanowhiskers under dynamic loading have various failure modes and better mechanical properties. 相似文献
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基于Kim的弹粘塑性单球壳塌缩模型,考虑PBX炸药中的粘结剂效应,假设炸药和粘结剂均为弹粘塑性材料,建立了弹粘塑性双球壳塌缩热点反应模型,给出了炸药球壳在冲击压力作用下的速度、应变、温度和化学反应速率的时空分布,以及新的热点反应速率理论表达式。把新的热点反应项与Kim的低压下慢反应项和张震宇提出的高压反应速率方程相结合,得到了新的冲击起爆三项式细观反应速率模型。把该模型加入DYNA2D中,模拟了PBX-9501炸药的一维冲击起爆过程,结果表明:该模型除了可以解释炸药颗粒度和孔隙度的影响外,还可以较好地描述粘结剂强度和含量对PBX炸药冲击起爆感度的影响。 相似文献
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Compressive Behavior of TATB Grains inside TATB-Based PBX Revealed by In-Situ Neutron Diffraction 下载免费PDF全文
《中国物理快报》2017,(6)
We investigate the(002)lattiee strain evolution of triaminotrinitrobenzene(TATB) grains inside one TATB-based plastic bonded explosive(PBX) through the in-situ neutron diffraction. By comparing the untreated specimen with the thermal-treated one, it is found that the volume-average response of measured TATB grains remains nearly elastic during quasi-static uniaxial compression. The observed changes in TATB(002) lattice strains correlate tightly with the evolution of damage. A damage parameter defined by the macroscopically determined residual strain is further used to describe the damage degree of PBX, which suggests that the compressive behavior of TATB-based PBX is significantly influenced by the damage evolution. 相似文献
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Experimental study on the micromechanical behavior of a PBX simulant using SEM and digital image correlation method 总被引:2,自引:0,他引:2
Zhongbin ZhouPengwan Chen Fenglei HuangSiqi Liu 《Optics and Lasers in Engineering》2011,49(3):366-370
The micro-scale mechanical behavior of a polymer-bonded explosive (PBX) simulant was experimentally studied using a scanning electron microscope (SEM) imaging system and digital image correlation (DIC) method. The semi-circular bend (SCB) test was chosen for the study. During the testing, a series of SEM images of the specimen was acquired in situ. The natural micro-structural features of the specimen were used as random speckle pattern for DIC analysis. The displacement and strain fields at the area of interest were obtained by DIC. The deformation and damage of PBX were analyzed. Heterogeneous strain fields demonstrated the damage evolution underneath the specimen surface and predicted possible micro-crack growth. Based on the contour plots of the correlation coefficient, the formation and extension of microscopic cracks were quantitatively analyzed. 相似文献