预应变下焊接接头冲击韧度及韧-脆转变的分析

以常用建筑结构钢(16Mn和Q235B)为研究对象，通过不同温度下的夏比冲击试验研究预应变对其母材和焊缝冲击性能的影响。结果表明，材料在预应变下无论是母材还是焊缝夏比冲击韧度均有所降低，韧一脆转变温度有所提高。5％预应变后的16Mn母材和焊缝其韧一脆转变温度均低于室温(20℃)，因此仍可在室温下安全使用；Q235B钢室温下冲击韧度较16Mn钢低，且预应变对母材影响更大，和未经预应变冲击值相比，降低了三倍有余。可以看出，Q235B钢的抗震性能较16Mn差。研究发现：为建立客观的材料韧度指标和进行更有效的安全分析时，预应变也应该作为一个考虑因素。     

电脑辅助钛合金人工髋关节锻件的开发

人工股骨柄是人工髋关节组件之重要分件 ,又是影响手术后人工髋关节使用寿命的重要因素 .由于人工股骨柄截面形状及细长比差异很大 ,为考虑钛合金锻造特性及省料、预成形之设计相当重要 ;本文针对钛合金人工髋关节股骨柄锻造工艺之设计要项 ,应用电脑辅助设计及锻造工艺模拟解析技术于锻坯和模具设计 ,期能缩短开发时程并降低开发成本     

酪素/蒙脱土插层复合物制备及其耐水性能研究

在十六烷基季胺盐存在下进行蒙脱土插层得到[H4N(CH2)15CH3]+-蒙脱土插层物,酪素加热溶解后与[H4N(CH2)15CH]+-蒙脱土插层物混合,保温复合,然后沉淀分离,得到干酪素/蒙脱土纳米复合物。用XRD,TEM和TGA表征酪素纳米复合物的结构与性能。结果表明,插层复合物中蒙脱土晶片间距扩大,插层复合物耐热性能明显提高,与纯酪素相比,复合物拥有极好的耐水性能,特别适用于制备高速高性能啤酒生产线用贴标胶。     

Poly(butylene terephthalate)/organoclay nanocomposites prepared by in situ interlayer polymerization and its fiber (II)

Intercalated nanocomposites with poly(butylene terephthalate) (PBT) incorporated between the montmorillonite layers were synthesized from dimethyl terephthalate and 1,4-butane diol by using an in situ interlayer polymerization. The PBT nanocomposites were melt-spun at different organoclay contents to produce monofilaments. The samples were characterized by using wide angle X-ray diffraction, electron microscopy, thermal analysis, and tensile testing. The extent of the clay layer in the PBT was confirmed by using X-ray diffraction and electron microscopy, and the clay layer was found to be highly dispersed on a nanometer scale. The addition of only a small amount of organoclay was enough to improve the thermo-mechanical properties of the PBT hybrid fibers. The hybrids were extruded with various draw ratios (DRs) to examine the tensile mechanical property of the fibers. At DR=1, the ultimate tensile strength of the hybrid fibers increased with the addition of clay up to a critical content and then decreased. However, the initial modulus monotonically increased with increasing amount of organoclay in the PBT matrix. When the DR was increased from 1 to 6, for example, the strength and the initial modulus values of the hybrids containing 3 wt% organoclay decreased linearly.     

A 3D analysis of the joint torques developed during driver's ingress–egress motion

Providing an easy ingress–egress (I/E) movement remains a challenge for car designers. I/E has been largely studied in kinematics, but not in dynamics. This study proposes: (1) to evaluate and describe the motor torques developed in the lower limbs and lumbar joints during I/E motions and (2) to analyse the influence of the car geometry and subject anthropometry. An experiment was performed to observe 15 subjects of three anthropometrical groups getting in and out of a car mock-up simulating three different vehicle configurations. Motor torques were extracted using an inverse dynamics analysis. Both ingress and egress motions were primarily characterised by large torques. Overall, the taller a subject and the lower the seat of the vehicle were, the larger the peak torques were. Moreover, peak torques were higher for egress than ingress. These results are discussed in regard to the current knowledge on I/E ergonomics.     

磁性油墨的研究进展

综述国内外磁性油墨的研究现状。分析了磁性油墨中的强磁性材料、连接料、填充料和添加料的各种分类、配比及各组分作用,探讨了磁性油墨的研究方向。首次指出:在今后的研究中应该采用纳米级的磁性颜料和复合磁性颜料,选用合成树脂作为连接料,并应重点研究添加料与磁性油墨性能的关系。     

纳米有机蒙脱土改性邻甲酚醛环氧树脂的研究

利用插层复合技术制备了邻甲酚醛环氧树脂／蒙脱土纳米复合材料，对固化产物利用X射线衍射(XRD)分析有机蒙脱土的层间距变化。通过对复合材料的力学性能测试表明，少量有机化蒙脱土的加入可以较大地提高材料的拉伸强度和冲击强度，起到了同时增韧增强的作用。并且环氧树脂／蒙脱土复合材料的热分解温度和热变形温度也有明显提高。     

三元乙丙橡胶/蒙脱土纳米复合材料的制备方法与应用前景

橡胶／蒙脱土纳米复合材料的优异性能使其成为橡胶工业中富有潜力的一类新型材料。笔者综述了三元乙丙橡胶(EPDM)／蒙脱土纳米复合材料的制备方法、性能和工业应用领域等，讨论了蒙脱土片层的表面修饰、插层剂的选择以及复合材料的制备方法对材料性能的影响，并提出了三元乙丙橡胶／蒙脱土纳米复合材料这一新型橡胶材料在轮胎工业上的应用前景。     

观音岩水电站厂房坝段接缝灌浆工艺

观音岩水电站装机容量 3 000 M W, 为一等大( ? ) 型工程。厂房坝段设置 5条横缝, 分为 6 个坝段。通过接缝 灌浆, 极大的改善厂房坝段受力条件, 提高大坝结构整体性和耐久性。结合观音岩水电站现场施工条件, 从施工角 度论述了接缝灌浆的施工工艺以及施工过程中可能存在的问题及处理方法。     

Mechanical behaviour of a combined joint composed of mechanical fastening and adhesive bonding

A study has been made of ‘combined’ joints consisting of mechanical fastening and adhesive bonding between rigid adherends. The mechanical characteristics of such ‘hybrid’ butt and lap shear joints have been derived by theoretical analysis. Results from experimental tests in combined joints giver reasonable agreement with the theoretical equations relating joint load to deformation.