风电叶片叶根连接陶瓷垫圈对螺栓疲劳性能的影响研究

首先利用Catia软件建立了风电叶片叶根模型,在专业网格划分工具中划分网格,采用商用有限元软件进行分析,结合有限元分析结果和载荷Markov矩阵,通过Matlab软件编写的疲劳损伤程序进行损伤分析,最终得到螺栓的损伤数值。比较了螺母下陶瓷垫圈存在与不存在时的螺栓应力,并分析了垫圈的存在对螺栓疲劳性能的影响。仿真结果表明采用螺母下放置陶瓷垫圈的方法可使螺栓损伤显著降低,疲劳性能有效提高。     

A new energy-absorbing bolt used for large deformation control of tunnel surrounding rock

In order to control the large deformation of tunnel surrounding rock, a new energy-absorbing bolt is developed. This bolt can be transformed into a rigid support when the deformation of the surrounding rock reaches the length of the sleeve tube, thus preventing the surrounding rock from continuing to deform. Moreover, this bolt has a simple structure and is easy to manufacture and assemble. Then the static tensile test is conducted on the bolt specimen to test its working performance. The test results show that when the cone angle of the cone block is small, the load–displacement curve of the bolt contains three stages; when the cone angle is large, the load–displacement curve contains only two stages. Meanwhile, both the average constant resistance and the maximum absorbed energy increase linearly with the increase of cone angle. On this basis, ignoring the influence of shear stress, and it is supposed that the thickness of the sleeve tube is constant, then the theoretical calculation formula of constant resistance for the new bolt is derived, and the rationality of the formula is verified using the static tensile test results. It is found that the error of the calculated result is less than 15% when the cone angle does not exceed 15°. At last, the numerical simulation method is used to analyze the performance of the new bolt. The simulation results indicate that the generation of shear stress and the change of tube thickness during the movement of the cone block are two important factors that cause theoretical errors.     

A novel rock bolting system exploiting steel particles

The effectiveness of rock bolting in ground control has been extensively investigated, mainly for resin based systems. Alternative coupling materials are needed to have good mechanical performance and to reduce the economic impact. This study proposed a new bolting system exploiting steel particles as coupling material. The applicability of this system was assessed by laboratory and field pullout tests, assisted by digital imaging correlation (DIC), infrared thermography (IRT) and acoustic emission (AE). The results indicated that, for a 20 mm diameter bolt, the suitable steel particle size and corresponding inner diameter of borehole were 1.4 and 28 mm, respectively. For bolts installed in steel tubes, the particles improved the loading capacity compared to the resin bonded ones. Additional pullout tests on cement blocks indicated that steel particles can be effective for hard rock, whilst resin was a better choice for bolting of soft rock. Similar understanding was obtained by pullout tests in engineering fields, which demonstrated that the steel particles coupled bolts can provide favorable effects in hard rock mass, while the effects were negligible when installed in extremely soft coal mass. The wide set of multi-technique measurements helped to understand the mechanisms involved in the performance of the bolting system with coupling steel particles.     

基于自注意力机制的桥梁螺栓检测算法

基于构建的真实桥梁螺栓场景数据集,提出基于自注意力机制与中心点回归（SACPR）的螺栓检测算法. 构建基于真实场景的高质量桥梁螺栓场景数据集,并针对数据不均衡、多样性不够的问题,使用数据增强方法进行数据扩充,从而获得更高的分类精度. 采用基于深度学习框架的SACPR算法检测不同场景下的螺栓,并进行标示. 对螺栓检测准确率进行验证实验,验证SACP算法的有效性. 将试验结果与YOLOv3、Faster-RCNN、RetinaNet这3种算法结果进行对比,发现3种检测方法的识别精度分别为80.56 %、87.71%、93.89%,而所提出的SACPR 算法的识别精度为93.91%,明显优于YOLOv3算法和Faster-RCNN算法;虽然SACPR算法与RetinaNet算法的识别精度较接近,但前者的检测速度是后者的5.6倍.     

GO7-23-5206井组凝胶调剖设计及效果分析

井间动态连通性是油藏动态分析的重要内容之一。孤东七区具有高孔高渗、强非均质、储层结构疏松、易出砂的特征。由于孤东油田水驱不均匀,使注入水在平面上形成水驱水流优势通道,从而有可能降低水的扫驱效率。针对这一严峻形势,先用流管图模拟出大孔道以及具有注采对应关系的注水井组。为后期调剖,选井选层提供重要的依据。并且通过连通性分析可以判别水流优势通道分布,最终达到提高采收率的目的。系统开展窜流通道定量化调剖技术提高采收率的研究。选定了一个具有代表性的典型注水井组,以凝胶为调剖剂,利用CMG软件,通过对凝胶的注入量和注入时间,从而确定注入速度,最后根据投入产出比,优选出最合适的方案,并在现场实施中获得良好的效果。     

氨合成塔主螺栓局部受损后的安全评定

对氨合成塔的主螺栓的损坏情况作了强度校核 ,有限元分析和安全性评定 ,提出可以继续承载的依据和运行中需注意的问题。     

柱塞泵蜗轮箱异常磨损的原因分析及改进

分析柱塞泵运行中蜗轮箱产生异常磨损和零部件失效的原因,进行了技术改进和旧件的修复夏利用后,泵运行正常,减少了维修工作量,取得了较好的经济效益。     

法兰连接螺栓断裂失效的分析研究

某装置多根法兰连接螺栓发生断裂,经化学成分分析、金相分析、断口的微观形貌、宏观形貌分析、腐蚀产物的能谱分析等一系列研究分析,确定该螺栓含碳量偏高,且处于腐蚀环境,失效为晶间型的应力腐蚀导致的断裂失效,并对如何预防该类连接螺栓再次发生失效提出建议。     

Computer simulation to predict stresses, working pressures and deformation modes in near-net shape heading of a tapered circular bolt with a square head

The incremental near-net shape heading of a circular rod to form a round but tapered bolt with a flat square head at one end is simulated using both a free body equilibrium approach based on the slab method of analysis and an upper bound analysis. With the aim of obtaining a well-formed component with no or little excess material, axisymmetric cylindrical billets made of model material tellurium lead and commercially pure aluminium, with different length to diameter ratio's, were forged progressively to ascertain the mechanics of metal flow in the upset process, and the characteristic deformation modes were studied. The results of die loads estimated from these analytical approaches are compared with those obtained experimentally and the results are discussed.     

发动机应力螺栓电热镦模锻研究

以150和396系列大功率高速柴油机应力螺栓的电热镦模锻为研究对象,分析了应力螺栓电热镦模锻工艺,介绍了应力螺栓锻模优化设计的要点,给出了锻件外方部分几何尺寸的关系式和锻模模膛内对边最小宽度尺寸的计算公式,找到了确保应力螺栓错移量和高精度电热镦模锻成形的有效方法,提高了锻件质量、锻件合格品率、锻造效率和锻模使用寿命,降低了锻件制造成本。