Machine fault diagnosis with small sample based on variational information constrained generative adversarial network

In actual engineering scenarios, limited fault data leads to insufficient model training and over-fitting, which negatively affects the diagnostic performance of intelligent diagnostic models. To solve the problem, this paper proposes a variational information constrained generative adversarial network (VICGAN) for effective machine fault diagnosis. Firstly, by incorporating the encoder into the discriminator to map the deep features, an improved generative adversarial network with stronger data synthesis capability is established. Secondly, to promote the stable training of the model and guarantee better convergence, a variational information constraint technique is utilized, which constrains the input signals and deep features of the discriminator using the information bottleneck method. In addition, a representation matching module is added to impose restrictions on the generator, avoiding the mode collapse problem and boosting the sample diversity. Two rolling bearing datasets are utilized to verify the effectiveness and stability of the presented network, which demonstrates that the presented network has an admirable ability in processing fault diagnosis with few samples, and performs better than state-of-the-art approaches.     

高精度测微计在车轴测量机上的应用方案

介绍了高精度测微计用于车轴直径测量的基本结构、关键技术及其在车轴测量设备上的应用。     

基于改进耦合增强随机共振的滚动轴承故障诊断

针对强背景噪声下经典随机共振方法对滚动轴承故障特征提取效果差的问题,提出了一种基于改进耦合增强随机共振的滚动轴承故障诊断方法。首先,利用一个定参双稳系统和一个变参双稳系统构成耦合随机共振系统,外部输入直接作用于定参双稳系统;然后,通过调节变参双稳系统参数和耦合系数实现耦合系统的随机共振控制,并借助遗传算法实现控制参数的自适应选取。实验和工程应用验证了所提方法的有效性和优越性。     

深井超深井钻井堵漏材料高温老化性能评价

深井超深井钻进裂缝性油气层极易发生频繁的钻井液漏失,造成严重储层损害和重大经济损失。储层段钻进过程中经常发生重复性漏失,意味着仅用酸溶率、粒度分布等常规堵漏材料评价指标已不能满足钻井液漏失控制工程需要。笔者以塔里木盆地克深气田钻井常用的核桃壳、毫米级碳酸钙为研究对象,开展了堵漏材料高温老化评价实验。实验评价结果表明,在180℃的柴油中老化24 h后,核桃壳的颜色由黄色变成黑色,质量损失率为25.16 % ,摩擦系数下降28.24 % ,抗压强度下降21.21 % ;毫米级碳酸钙的颜色由白色变成淡黄色,质量损失率为2.47 % ,摩擦系数下降1.33 % ,抗压强度基本不变;由高温老化后的核桃壳和毫米级碳酸钙所形成的封堵层,其承压能力下降了48.84 % 。分析指出,堵漏材料高温老化失效是深井超深井裂缝封堵层结构破坏并在储层段发生重复性漏失的一个重要因素。     

A multi-step progressive fault diagnosis method for rolling element bearing based on energy entropy theory and hybrid ensemble auto-encoder

It is meaningful to efficiently identify the health status of bearing and automatically learn the effective features from the original vibration signals. In this paper, a multi-step progressive method based on energy entropy (EE) theory and hybrid ensemble auto-encoder (HEAE), systematically blending the statistical analysis approach with the deep learning technology, is proposed for rolling element bearing (REB) fault diagnosis. Firstly, a preliminary detection about the REB health status is performed by the statistical analysis technique integrated with the EE theory. Secondly, if fault exists in REB, a new HEAE is constructed based on denoising auto-encoder and contractive auto-encoder to strengthen the feature learning ability and automatically extract the deep state features from the raw data. Subsequently, a modified t-distributed stochastic neighbor embedding (M-tSNE) algorithm is developed to achieve the features reduction to further improve the diagnosis efficiency. Finally, the low-dimensional representations after features reduction are as the inputs of softmax classifier to recognize the fault conditions. The proposed method is applied to the fault diagnosis of REB. The results confirm the effectiveness and superiority of the proposed method, and it is more suitable for the actual engineering applications compared with other existing methods.     

注剂式带压密封新型四等分夹具性能分析

以突面对焊钢制管法兰的注剂式带压密封为研究对象,分别建立其通用型夹具与新型四等分夹具的有限元模型,并运用ABAQUS有限元软件分析通用型夹具和新型四等分夹具的力学性能。结果表明:当压力为6 MPa时,新型四等分夹具周向最大拉应力为通用型夹具的66.97%,螺栓最大拉应力为通用型夹具的38.16%,形变位移为通用型夹具的93.65%。新型四等分夹具在承压能力、应力集中方面都优于通用型夹具,因而具有更高的承压能力和使用寿命。     

油水混合对径向滑动轴承润滑性能的影响

基于流体动压润滑基础理论,利用数值计算方法,在MATLAB软件中建立径向滑动轴承油水混合动压润滑的数学模型,对比分析润滑油中不同含水量对径向滑动轴承润滑性能的影响。结果表明:润滑油中混入少量的水对滑动轴承液膜的厚度和压力产生了一定的影响,最小液膜厚度随含水量的增加而减小,最大液膜压力随含水量的增加而增加;润滑油中混入少量水使得液膜合力和摩擦力变大,将不利于轴承的动压润滑,从而导致轴承润滑性能变差,并且加大轴承的摩擦磨损,降低径向滑动轴承的使用寿命。     

界面滑移对圆柱形凹坑织构滑动轴承摩擦力的影响

为研究不同的滑移情况对圆柱形凹坑织构滑动轴承摩擦力的影响,建立含有圆柱形凹坑织构的滑动轴承在不同界面滑移状态下的摩擦力计算模型,探究影响织构化滑动轴承摩擦力的参数,并借助ANSYS分析不同滑移情况下界面滑移对圆柱形凹坑织构滑动轴承摩擦力的影响规律。结果表明:织构化滑动轴承的摩擦力主要是由轴颈线速度、油膜滑移比、轴承的进出油口压力、织构处油膜压力、织构深度、油膜厚度和承载力决定;不同滑移情况下织构模型的摩擦力均小于无织构模型;且在上下表面均滑移时,圆柱形凹坑织构在出口位置时表现出最优的承载和减摩效果;适当地增加圆柱形凹坑织构的深度可以改善模型的摩擦性能,但是过深的凹坑织构并不能发挥出其性能。     

热效应影响下浮环轴承润滑静特性研究

建立计入热效应的浮环轴承流体动压润滑模型,利用数值差分法联立求解雷诺方程,进而求解浮环轴承端泄流量;通过与实验数据的对比,验证所建模型的正确性;考虑浮环受热膨胀变形的影响,研究供油温度对摩擦功耗、温升、浮动环转速、端泄流量等浮环轴承润滑静特性参数的影响。结果表明:提高润滑油供油温度会明显提升浮动环旋转速度,增大轴承内间隙的供油量,减小内外油膜摩擦功耗和端泄温升;端泄温升随轴颈转速的升高而增大,温升随轴颈转速变化的幅度在采用较低温度的润滑油时表现得更为剧烈。