Torque Transmission Capabilities of Bonded Polygonal Lap Joints for Carbon Fiber Epoxy Composites

Although carbon fiber epoxy composite materials have excellent properties for structures, the joint in composite materials often reduces the efficiency of the composite structure because the joint is often the weakest area in the composite structure.

In this paper, the effects of the adhesive thickness and the adherend surface roughness on the static and fatigue strengths of adhesively-bonded tubular polygonal lap joints have been investigated by experimental methods. The dependencies of the static and fatigue strengths on the stacking sequences of the composite adherends were observed.

From the experimental investigations, it was found that the fatigue strength of the circular adhesively-bounded joints was quite dependent on the surface roughness of the adherends and that polygonal adhesively-bonded joints had better fatigue strength characteristics than circular adhesively-bonded joints.     

单螺杆泵井工况智能综合诊断系统的设计

本文介绍一种单螺杆泵井工况智能综合诊断系统。本系统由数据采集和数据处理与智能分析两部分组成,可以进行单螺杆泵井下工况实时监测,并及时提供有关螺杆泵的转速、扭矩、载荷、电流、电压以及井口油套压和液面等。本文还介绍了本系统的安装和应用,通过数据处理和实际数据与理论数据的比较,可以指导螺杆泵井的维护。     

高转速、无稳心搅拌装置介绍

本文介绍了一种特殊的高转速、无稳心搅拌系统，具备简洁、高效、稳定、安全的特点，经使用证明，效果良好，性能可靠，为高速搅拌及无稳心反应釜的应用提供了一条新的设计及运用的途径。     

反应加工制备接枝聚合物的研究进展

综述了利用哈克转矩流变仪及采用反应挤出法制备接枝聚合物的特点及接枝体系的选择。另外，以马来酸酐为例，阐述了接枝反应的机理，同时总结了几类可通过反应挤出进行接枝改性的聚合物，并对接枝聚合物的应用进行概括。关于接枝物的表征，主要从纯化方法、接枝的确定、接枝率的测定方法等方面进行了概述。     

EVOH／有机蒙脱土插层复合材料的制备与表征

将经有机化处理过的蒙脱土与EVOH熔融共混制备插层复合材料，并对该复合材料进行了XRD分析，分析结果表明：聚合物基体已经插入了有机蒙脱土片层间；复合体系中蒙脱土含量越小，蒙脱土被插开的片层间距越大；当复合体系中有机蒙脱土含量≤8％时，形成剥离型复合材料；当有机蒙脱土含量在8％～15％时，形成插层型复合材料；当有机蒙脱土含量大于15％时，复合材料中蒙脱土片层间距无明显变化。对EVOH与蒙脱土熔融共混过程的扭矩分析表明：该复合材料熔融混合9min之后，达到均匀混合和完全塑化的状态。     

基于电流矢量和开关表格控制的异步电机控制方法

采用矢量控制技术控制电机,在连续控制上有很大的优势,但它对被控电机的参数要求很高,且计算繁琐。直接转矩控制技术计算相对简单很多,它简化了控制结构,直接对转矩和磁链进行砰-砰控制,低速性能较差,调速范围受到比较大的限制。鉴于上述两种控制方法的优缺点,本文提出一种新型三相电机控制方法,仿真表明,这种新型的控制方法继承了矢量控制和直接转矩控制的部分优点,又抑制了这两种控制方法性能上的一些不足。     

永磁同步电机的一种转矩估计算法分析

转矩估计的前提是磁链观测,采用改进的电压法对磁链进行观测.考虑到定子电阻的影响,对基于dq轴方程的模型参考自适应系统的辨识方法进行了详细的计算分析,并发现该电阻辨识算法具有收敛值不唯一的可能,而仪使用q轴方程的辨识算法能克服这一问题.在此基础上建立了基于矢量控制的永磁同步电机系统仿真模型,并验证了算法的有效性.     

EPDM／NBR并用胶增容体系的研究

采用ＨＡＡＫＥ扭矩流变仪考察了不同的增容剂对ＥＰＤＭ／ＮＢＲ并用胶混炼特性及硫化特性的影响．并采用溶解凝胶法进行了验证实验。同时研究了不同增容剂及其用量对并用胶力学性能的影响。结果表明：增容剂ＥＶＡ－１４、ＥＶＡ─２８、ＣＰＥ及磺化乙丙橡胶（Ｓ─ＥＰＤＭ）均能改善ＥＰＤＭ／ＮＢＲ体系的相容性．但ＥＶＡ－１４的增容效果更好；加入增容剂后并用体系的均化分散时间明显缩短，交联程度得到了提高。     

Development of a Failure Model for the Adhesively Bonded Tubular Single Lap Joint

The accurate calculation of the stresses and torque capacities of adhesively bonded joints is not possible without understanding the failure phenomena of the adhesive joints and the nonlinear behavior of the adhesive.

In this paper, an adhesive failure model of the adhesively bonded tubular single lap joint with steel-steel adherends was proposed to predict the torque capacity accurately.

The model incorporated the nonlinear behavior of the adhesive and the different failure modes in which the adhesive failure mode changed from bulk shear failure, via transient failure, to interfacial failure between the adhesive and the adherend, according to the magnitudes of the residual thermally-induced stresses from fabrication.     

Enhancing diamond drilling performance by the addition of non-ionic polymer to the flushing media

Drilling is a most important and crucial operation in the excavation industries.With the objective of looking into the enhancement of diamond drilling performance detailed laboratory investigations were carried out on phosphate rock.The effect of Poly (Ethylene Oxide) (PEO) added to the drilling water was studied by varying machine parameters and PEO concentration.The responses were rate of penetration and torque at the bit rock interface.Slake durability tests were also performed to understand the slaking behavior of phosphate rock in PEO solutions.