幂律全塑性罚函数随机有限元

用罚函数有限元方法解决平面应变下的体积下可压缩问题,应用摄动有限元理论发展幂律全塑性随机有限元,并以弹性模是E,泊松比u和节点坐标等的基本随机变量,推导有限元列式,给出单板受拉,梁受弯的算例。     

断裂分析中的随机有限元方法

以单边裂纹板为例给出计算断裂参数;J（J积分）、δ（裂纹张开位移）、△c(由裂纹引起的上、下端面的相对位移）、θc(由裂纹引起的上=下端面的相对转角）及其对基本随机变量变化率的随机有限元方法。     

不同衬底上Pb(Zr0.52Ti0.48)O3择优取向铁电薄膜的制备和研究

通过MOD法在Si(100)和Pt(111)/Ti/SiO₂/Si基片上制备出LaNiO₃ ( LNO)薄膜.再通过修 正的Sol-gel法，在Pt(111)/Ti/SiO₂/Si,LNO/Si(100)和LNO/Pt/Ti/SiO_{2< /sub>/Si三种衬底上 制备出具有择优取向的Pb(Zr0.52Ti0.48)O3铁电薄膜. 经XRD分析表明，L NO薄膜具有(100)择优取向的类钙钛矿结构；PZT薄膜均具有钙钛矿结构，且在Pt(111)/Ti/S iO2/Si衬底上的薄膜以(110)择优取向，在LNO/Pt/Ti/SiO2/Si和LN O/Si(100)衬底上的 薄膜以(100)择优取向.经场发射SEM分析和介电、铁电性能测试表明，在LNO/Si和LNO/Pt/Ti /SiO2/Si衬底上的PZT薄膜的平均粒径、介电常数以及剩余极化强度均比以Pt/T i/SiO2/Si为衬底的薄膜大. 关键词： 3}薄膜')" href="#">LaNiO₃薄膜 PZT铁电薄膜 择优取向 剩余极化强度     

穿透短裂纹的预制和长度测定与处理

本文介绍了一次开裂多序加工的预制穿透短裂纹方法，并建议采用直接观测和复型校核的短裂纹测量方法，并用面积等效处理短裂纹长度。     

在LaNiO3-Pt复合电极上Pb(Zr，Ti)O3铁电薄膜及其成分梯度薄膜的制备和研究

LaNiO₃(LNO) thin films were prepared on Pt(111) / Ti / SiO₂/ Si substrate by metal-organic decomposition (MOD) method. Pb(Zr,Ti)O₃ ferroelectric thin films and their compositionally graded thin films were prepared on LNO / Pt / Ti / SiO₂ /Si substrates by Sol-gel method. The composition depth profile of a typical up-graded film was determined by using a combination of Auger Electron Spectroscopy (ASE) and Ar Ion Etching. The results confirm that the processing method produces graded composition changes. XRD analysis showed that the graded thin films possessed composite structure of tetragonal and rhombohedral. The dielectric constants of Up-graded and Down-graded thin films were higher than that of each thin film unit. The dielectric constants were 277 and 269 at 10 kHz, respectively. The loss tangents were 0.019 and 0.018 at 10 kHz, respectively. The Hysteresis loops showed that the remanent polarizations of graded thin films were higher than that of each thin film unit, but the coercive fields were smaller. The remanent polarizations of Up-graded and Down-graded thin films were 30.06 and 26.96 μC·cm^-2, respectively. The coercive fields were 54.14, 54.23 kV·cm^-1, respectively. The pyroelectric coefficients of Up-graded and Down-graded thin films were 4.62, 2.51×10^-8 C·cm^-2·K^-1 at room temperature, respectively. They were higher than that of each thin film unit.     

反射型云纹法在爆炸加载超动态实验力学中的应用

本文介绍对爆炸加载反射型动态云纹实验方法进行的研究,利用高速转镜相机记录了橡胶板、聚碳酸酯板及岩石介质爆炸加载实验时的动态云纹图,并进行了初步定量分析。实验证明,反射型云纹法用于爆炸加载的超动态量测是可行的。它为岩石爆破动力学问题研究提供了一种新的有效技术。     

新型双呋咱并[3,4-b∶3’,4’-f]氧化呋咱并[3″,4″-d]氧杂环庚三烯的合成与量子化学研究

以3,4-双(4’-硝基呋咱-3’-基)氧化呋咱为原料,设计并合成了新型双呋咱并[3,4-b∶3’,4’-f]氧化呋咱并[3″,4″-d]氧杂环庚三烯(1),收率50.1%,其结构经13C NMR,15N NMR,IR,MS和元素分析表征。最佳的反应条件为:以无水碳酸钠为催化剂,乙腈(含水量0.04%)为溶剂,于80℃反应3.5 h。用B3LYP方法在6-31G**基组水平上对1的结构进行了计算,得到了稳定的几何构型和键级。在振动分析的基础上求得体系在不同温度下的热力学性质,得到了温度对热力学性能影响的关系式。1的性能研究表明,1的m.p.92℃～94℃,爆速8 256m.s-1(1.85 g.cm-3),摩擦感度0%(90°摆角),撞击感度12%(10 kg,25 cm),特性落高H50=57.5 cm(5 kg)。     

纯幂律全塑性罚函数有限元

从非线性连续介质力学出发导出一种新的形式较简单的纯幂律体积不可压缩一构方程,形成纯幂律罚函数有限元。提出迭代解分析方法论羰应变条件下罚函数方法有效性。再结合计算结果讨论不同条件下罚因子对应在力应变场的影响并对迭代特性进行分析。结果发现纯幂律全塑性罚函数有限元存在;１）迭代收敛速度随害虫律指数增加而减慢,并且εｅ〉ε０时减幅很大;εｅ〈ε０时不明显。２）应力应变的计算精度随幂律指数变化而变化,当ε〉