钢丝绳检测数据的可靠性评定方法

该系统对钢丝绳试验站检验数据及日数据微机处理。通过原始数据的录入，可以自动生成成试验站用各种报表、判断是否符合《煤矿安全规程》并进行可靠性评定。     

Multi-scale strength analysis of bolted connections used in integral thermal protection system

Efficient and accurate strength analysis of bolted connections is essential in analyzing the integral thermal protection system(ITPS) of hypersonic vehicles, since the system bears severe loads and structural failures usually occur at the connections. Investigations of composite mechanical properties used in ITPS are still in progress as the architecture of the composites is complex. A new method is proposed in this paper for strength analysis of bolted connections by investigating the elastic behavior and failure strength of three-dimensional C/C orthogonal composites used in ITPS. In this method a multi-scale finite element method incorporating the global–local method is established to ensure high efficiency in macro-scale and precision in meso-scale in analysis.Simulation results reveal that predictions of material properties show reasonable accuracy compared with test results. And the multi-scale method can analyze the strength of connections efficiently and accurately.     

Damage characteristics and constitutive modeling of the 2D C/SiC composite: Part Ⅱ–Material model and numerical implementation

In this work, a macroscopic non-linear constitutive model accounting for damage, inelastic strain and unilateral behavior is proposed for the 2D plain-woven C/Si C composite. A set of scalar damage variables and a new thermodynamic potential expression are introduced in the framework of continuum damage mechanics. In the deduced constitutive equations, the material's progressive damage deactivation behavior during the compression loading is described by a continuous function, and different deactivation rates under uniaxial and biaxial compression loadings are also considered. In damage evolution laws, the coupling effect among the damage modes and impediment effect of compression stress on the development of shear damage in different plane stress states are taken into account. Besides, the general plasticity theory is applied to describing the evolution of inelastic strain in tension and/or shear stress state. The Tsai–Wu failure criterion is adopted for strength analysis. Additionally, the material model is implemented as a user-defined material subroutine(UMAT) and linked to the ABAQUS finite element software, and its performance is demonstrated through several numerical examples.     

热老化对APMOC和PBO拉伸性能的影响

为研究热对阿莫斯（APMOC）和聚对亚苯基苯并双唑（PBO）力学行为的影响,用高温干燥箱在温度100,120,150℃下分别对两者进行热老化实验,并对老化试样进行单丝拉伸测试和拉伸断口的电镜扫描观察（SEM）。实验结果表明：PBO具有较APMOC更优的热稳定性,在实验温度范围内,PBO的性能基本不变;AP-MOC在温度100,120℃处理时性能有所增强;老化对两种纤维模量的影响均很小,而断裂伸长率均有所下降;SEM发现纤维失效形式由原纤化向脆性断裂转变,与其他芳纶老化情形一致。     

缠绕角度对碳/环氧厚壁管件轴压性能影响的实验研究

文摘采用缠绕工艺制备了20°、30°和40°三种缠绕角度的碳/环氧厚壁管件,通过轴压实验研究了缠绕角度对厚壁管件的轴压模量和轴压强度的影响,并对轴压破坏模式进行了分析。实验测得轴向模量值比有限元模型计算值偏小,破坏模式为纤维层向外崩裂破坏与有限元分析结果一致。     

带CFRP箍环整体叶盘强度和寿命分析及试验

1引言随着叶轮机叶尖切线速度的日益提高,传统转子材料和结构的使用已经达到了极限。带碳纤维增强复合材料(CFRP)箍环整体叶盘(blisk)结构是上世纪90年代国外在风扇转子设计中采用的一种新型结构形式[1,2],其特点是在整体叶盘叶尖位置有金属外环,在外环上带有CFRP箍环,叶片的部     

固体火箭发动机的概率设计

固体火箭发动机的性能参数和结构参数一般都服从正态分布，利用应力－强度干涉理论，通过正态分布密度函数的耦合方程进行发动机结构设计，并推导出具有随机变量指数的发动机工作压强和燃烧室壳体弹塑性爆破压的均值和标准偏差表达式，导出传统安全系数与可靠概率的关系。该设计方法较之传统的采用安全系数的设计方法合理。     

基于层合板基本性能数据的复合材料层合结构的强度校核方法

通过对[0/45]_8,[0/9]_8两种铺层的玻璃/环氧管状试样做双向载荷强度实验,发现基于层合板基本强度数据的Tsai—Wu准则失效包络线比基于单向板基本性能数据的失效包络线与实验结果的吻合要好得多。特别是按两个单轴强度比值做双轴强度实验确定相互作用系数,其强度曲线比选取相互作用系数F_(xy)~(?)=-1/2的方法与实验结果更为吻合。     

碳纤维强度的计算机研究

本文用计算机程序确定三参数威布尔分布函数中的三个参数，并以实验获得的单丝强度数据比较了三参数威布尔分布和正态分布以及二参数威布尔分布的适用性。结果表明：纤维束中占大多数的中等强度单丝，其强度较符合威布尔分布；少量较低或较高强度单丝较符合正态分布。比较二参数和三参数威布尔分布发现，在某些实验样本范围内，两者相差较少，而在另一些情况下，基本上不能用二参数威布尔函数来描述。为提高统计分析的可靠性，建议采用三参数威布尔分布。另外，本文还进行了纤维束断裂过程的计算机模拟，其结果和实际情况符合得较好。     

超掺粉煤灰混凝土的工程应用研究

粉煤灰的综合利用是目前的研究热点。本文阐述了采用超量取代法配制大掺量粉煤灰混凝土的工程应用技术的研究，从配合比设计、施工质量控制几个方面着手分析，并对粉煤灰混凝土的和易性、强度和耐久性进行检验，证实大掺量粉煤灰混凝土在工程应用技术上是可行的。