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121.
梳棉机生条结杂的研究与控制 总被引:8,自引:4,他引:4
为探讨梳棉机生条结杂的控制措施,研究了影响梳棉机生条结杂的主要因素,得出影响梳棉生条结杂的因素很多,情况也比较复杂,必须有针对性地加以处理,从原棉抓起,采用合理工艺,以最小成本来控制生条的结杂数量。 相似文献
122.
Marco Gettel 《Journal of Constructional Steel Research》2007,63(11):1467-1478
At present, there are only a few studies concerning the application of different types of buckling strength verification according to Eurocode 3 at combined loading. Besides the stress design as classical hand calculation method of checking cylindrical steel shells against buckling failure, the new Eurocode 3 also offers two global numerical analyses at different modelling levels. The linear buckling analysis (LBA) combined with a materially nonlinear but geometrically linear analysis (MNA) is the simpler concept from the perspective of the modelling and calculation effort. The more sophisticated method is a geometrically and materially nonlinear analysis of the imperfect structure (GMNIA). This paper presents the application of both numerical concepts to the cantilevered shell subject to a transverse load at the free edge. The results are compared to those from stress design. There are specific features at both types of numerical analysis: As the determination of the plastic reference resistance and the buckling parameters is the main focus at MNA/LBA, the choice of proper equivalent geometric imperfections demands special diligence at GMNIA. The presented analyses show that the GMNIA concept in connection with consistent equivalent geometric imperfections may lead to a safe and economic design of cylinders subject to combined loading. At the particular load case the MNA/LBA concept currently suffers from the lack of proper regulations concerning the determination of the overall buckling reduction factor. 相似文献
123.
The present work is an attempt to determine the oil film thickness in a medium-speed four-stroke diesel engine with a cylinder diameter of 200 mm. Experimental research on this topic was found necessary due to the limited amount of published information available with reference to engines of the present size. The experimental part of the study was carried out as firing engine tests, with an instrumented piston, equipped with telemetric data transmission, and an instrumented cylinder liner in a 6-in-line test engine. The study was carried out for different parts of the four-stroke working cycle and for different levels of engine power output. The results were compared with the results of computer simulations, carried out using a commercial software package. The conclusions of the study comprise aspects on the formation and development of the oil film between the rings and the liner under a set of load levels together with the periodical fluctuation during different strokes of the working cycle. 相似文献
124.
介绍了用自来水的供水压力替换液压油做动力源 ,运用到舞台升降机构中 ,取得了良好效果。探讨了在类似机构中使用自来水。 相似文献
125.
介绍了因二级汽缸吸气阀螺栓跌入二级汽缸上部造成氮压机机身断裂的事故,分析了事故原因,最后提出了事故的解决方法和预防措施。 相似文献
126.
在确定的液压系统中,油缸内泄漏的影响因素主要是油缸两腔的压差。在油缸负载保持状态下,针对由于内泄漏而产生的位移变化建立仿真模型。仿真结果表明:正装法下降速度更慢,油缸最终将因两腔压差消失而停在某一位置;倒装法下降速更快,且油缸两腔压差一直存在,油缸将持续下降。因此,在设备设计中,需要设备停位保持的工况,采用正装法能更好地满足要求。 相似文献
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C. Michael. Lindsay George C. Butler Chad G. Rumchik Ben Schulze Ryan Gustafson Warren R. Maines 《Propellants, Explosives, Pyrotechnics》2010,35(5):433-439
We report the development of a new methodology for analyzing CYLEX tests streak images. In these tests, the displacement of the wall of an explosive filled cylinder is obtained by backlighting the cylinder. The profile is imaged through a slit and streaked across a film record as the cylinder is detonated. A critical step in processing this data is the spatial calibration of the film and extraction of the profile of the cylinder from the image. Historically this has been a tedious task as it was performed by eye with the assistance of an optical comparator. Recently we developed an algorithm which automates the data calibration and extraction process of digitized streak records utilizing the Shen‐Castan edge detection algorithm and the image processing capabilities found in the IGOR PRO software. The new processing methodology greatly increases the resolution of the data, removes human subjectivity, and reduces analysis time from hours to seconds. The higher resolution of the new method has enabled much greater accuracy in measuring early‐time (<15 µs) expansion. With the aid of CTH hydrocode calculations, new fitting functions were developed to model both the early and late‐time expansion data. These functions contain physically meaningful fitting parameters and include terms which mimic the intensity and time scales of the shock and gas induced expansion of the cylinder independently. We demonstrate the methodology and hydrocode calculations on a recent CYLEX test series aimed at examining the effects of a plastic liner on high‐purity oxygen‐free copper cylinders filled with a high explosive. 相似文献