In this paper , based on the viscoelasticity theory and the dynamics theory , the finite element method ( fem ) is used to the structural integrality analysis of the grain in rocket engine of the base - bleed and rocket compound extended range projectile in chamber 本文基于粘弹性理论和动力学理论,运用ansys对某型号底排?火箭复合增程弹助推火箭发动机药柱在膛内的结构完整性进行了系统的分析。
The article introduces about the bridge semi - active algorithm ’ s present state and perspectives of ordinary viscoelasticity damp system and the magnetorheological damp system , and selects one standard test question , gives to the damp model with the procedure to realize 文章详细介绍了关于桥梁半主动算法的普通粘弹性阻尼系统和磁流变阻尼系统研究现状,并且选用了一个标准的测试问题,对阻尼模型用程序予以实现。
With engineering polymer - pmma taken as the main researched object and viscoelastic failure considered as the theory basis , the non - linear viscoelasticity and crazing damage phenomena under creep condition in macromolecule material were researched by means of experiment 本文以工程高聚物pmma为主要研究对象,以粘弹性破坏理论为基础,以实验为手段,对高分子材料蠕变条件下的非线性粘弹性性能及其银纹损伤现象进行了初步探讨。
For the polymer showing time - dependent character in many situations , the viscoelasticity should necessarily be taken into account in the general model . further , as the conventional j integral is no longer valid for hydrothermal materials cases , investigations on new energy - type fracture criter ia are specifically needed 此外,在含湿、热效应的高聚物材料中,传统的粘弹性或弹性材料的断裂判据不再适用,所以,对该问题进行研究也是十分必要的。
Performance for a piezoresistive transducer pressure sensor to thermal and pressure environments can be predicted by finite element method . a simplified 1 / 8 model , considering silicon dioxide and nitride process as well as stack anodic bonding and adhesive bonding processes , was developed . the fem results were found to be comparable to experimental data . case studies suggested that pyrex stack induces certain amount of non - linearity , while it isolates hard epoxy nonlinear effect . flexible epoxy bonding or soft adhesive bonding is preferred to the packaging process . the viscoelasticity and viscoplasticity of bonding material will result in hysteresis and drift errors to sensor output . however , soft adhesive s influence on sensor can be ignored under relative stable environments . more over , detailed design and process information will help to improve modeling application 热、压环境下压阻变换压力传感器的性能可以通过有限元方法预测.这里研究了简化的1 / 8模型,模型考虑了二氧化硅和氮化硅生成过程及堆阳极键合和胶粘结合过程.结果发现有限元预测结果和实验数据具有可比性.范例研究表明,硼硅堆导致产生一定的非线性,但它隔离了硬环氧树脂的非线性.在包装过程中最好使用柔性环氧黏合或软黏胶性结合.黏合材料的黏弹性和黏塑性将会导致传感器输出的滞后和漂移误差.然而,在相对稳定的环境下,软黏合剂对传感器的影响可以忽略.此外,详细的设计和过程信息有助于提高模型的适用性
From the hypothesis of linear viscoelasticity , we predicted the time of life of the three specimens with edge crack which fractured in out experiment at last in view of energy releasing . however , we found that the predicted values were on the low side obviously , so we analyzed the reason of being non - linear . on this basis , we modified the method 本文的第四章从线粘弹性假设出发,从能量释放率的角度对实验中最终断裂的三今含边裂纹的试件的寿命进行了预测,并与实验结果进行了对比,发现预测值明显偏低,分析了产生非线性的原因,进行了非线性修正。
By means of the finite element inverse analysis , based on stress - strain theoretical equations of the elastoplasticity and viscoelasticity - viscoplasticity , the change of the valley - side margin stress distribution during original state , the condition of human cutting a terrace of building houses in the loess slope , and the condition of cutting the top of loess slope is elucidated 3 .基于粘弹?粘塑性理论的本构方程,运用有限元方法进行反演分析,阐明了宅基边坡谷缘在天然条件、斩坡建窑条件下和削坡条件下的应力场变化特点。结果表明,谷缘在斩坡建窑条件下拉张应力和剪切应力增大是导致崩塌产生的根本原因。
Graphite ) and the special viscoelasticity of polymer , interlayer exfoliation of the filler and its nanocompounding with polymers can be realized in the shearing force field of pan - milling , through the effects such as deformation , dislocation , tension - sliding and shearing exfoliation of graphite , the tension - thinning , pulverization of pp , as well as the imbedding , mixing and dispersion of graphite flakes in pp powder etc . the results show that the interlayer exfoliation of graphite and nano - compounding with pp proceeded stepwise , caused by a combination of friction , squeezing , stretching , and shearing in three - dimension during pan - milling 石墨片层的受限空间影响i一pp / yep25o复合材料中pp结晶行为,进入石墨片层间的pp分子一部分择优取向,形成沿( 040 )晶面法线方向择优生长的a一晶,另一部分相对分子质量较小、运动活性较高的pp分子则受到石墨片层的挤压和限制而转化为y -晶,在i一pp厅ep250复合材料中, y -晶相对含童达34 . 8 % 。
At present , many important development on the studies of viscoelastic theory have been made by the efforts of scholars home and abroad , linear viscoelasticity theory has sufficiently developed , while nonlinear viscoelastic theory is still under developed by the reason of difficulties in experiment and mathematics 目前,国内外学者在粘弹性理论研究领域取得了许多重要的研究进展,线粘弹性理论已发展得较为完善,非线性粘弹性理论由于实验和数学上存在的困难尚处于不断的发展和完善之中。
( 4 ) only when the resistance r = l / c , the transition efficiency between electric energy and heat reach its maximum value , which makes it possible to design the high performance damping composites of multi - energy transitions by adjusting the vgcf content . cpe / zkf / vgcf composites : in the cpe / pzt / vgcf composites , the conversion efficiency from force to electricity is very low because of the obvious difference of rigidity between cpe and pzt , which leads to the damping effect of multi - energy transitions is not so evident as the viscoelasticity of the matrix cpe , especially during the cpe glass transition Cpe / zkf那gcf复合材料:针对cpe / pzt / vgcf复合材料中由于cpe和pzt之间模量差异较大,导致cpe和pzt之间的应力传递欠佳,影响力一电变换效率,从而压电导电减振作用效果并不十分显著的现象;本章中采用极性有机小分子双( 2一轻基- 3一环己基一5一甲基)一苯基]甲烷( zkf ) ,而不采用pzt ,消除了pzt与cpe模量方面差异的影响。
Viscoelasticity is the property of materials that exhibit both viscous and elastic characteristics when undergoing deformation. Viscous materials, like honey, resist shear flow and strain linearly with time when a stress is applied.