单个透水丁坝对溢洪道泄槽弯道水流流态影响试验研究

为了研究单个透水丁坝对溢洪道泄槽弯道水流流态的影响,采用PVC板制作试验模型,进行了溢洪道泄槽弯道凹岸3个位置(1/4、1/2、3/4弯道处)、3个角度(45°、60°、75°)布置单个透水丁坝的水力学试验。利用试验结果,分析了溢洪道泄槽弯道水面均匀度、弯道横断面最大水面横比降、壅水曲线等弯道水流特征。结果表明,与无透水丁坝相比,弯道内布置单个透水丁坝后的弯道水面均匀度均有增加;单个透水丁坝布置角度为60°或75°时,弯道横断面最大水面横比降减小。在布置角度相同、布置位置不同的条件下,单个透水丁坝在弯道1/4处引起的壅水曲线的长度最短;在弯道1/4处,当单个透水丁坝布置角度为60°或75°时,弯道内的壅水曲线长度最短;在弯道1/2或3/4处,当单个透水丁坝布置角度为75°时,弯道内的壅水曲线长度最短。     

塔里木盆地玛扎塔格弧形构造及斜向逆冲

塔里木盆地巴楚隆起南部边缘玛扎塔格山地表构造为一倾向南的新近纪单斜地层,而中深部则为凸向北玛扎塔格背斜弧形构造带。根据该区构造展布特征,依据地震和钻井资料,对玛扎塔格构造进行了详细分析研究。首先从平面上分析了该构造主挤压应力方向,然后建立起弧形构造不同部位构造接触关系,引进斜向逆冲断层褶皱概念,分析了所解释的地震剖面,并对其进行部分平衡恢复。结果表明:弧形构造主挤压应力方向垂直弧顶(中部),与弧形构造东、西两段斜交;弧形构造中部与东段之间发育撕裂断层——玛4井东走滑断层,弧形构造中部与西段之间的分界构造为玛7井西侧向断坡;无逆冲断层的部分恢复剖面显示弧形构造中部位移较为均衡,古生界地层从上到下缩短量基本一致,说明构造基本上为纯挤压作用形成的滑脱褶皱;弧形构造西段滑脱褶皱北翼的寒武系—奥陶系地层缩短量大于石炭系—二叠系地层缩短量,说明滑脱褶皱的北翼存在斜向剪切作用,其形成的构造可与混合剪切断层弯曲褶皱类比;而弧形构造东段的部分恢复剖面表明中上寒武统—中下奥陶统缩短量增加很快,而石炭系—二叠系缩短量逐渐减少,说明该构造存在斜向剪切作用,其形成的褶皱类似于简单剪切断层弯曲褶皱;玛扎塔格弧形构造属于旋转弧形构造类型,即早期平直构造被晚期挤压导致逐渐弯曲形成的弧形构造,这与剖面上观察到的生长地层得到变形时间认识完全一致。     

中俄东线－45 ℃低温环境油气管道工程用X80钢级Φ1 422 mm×33.8 mm感应加热弯管研发

为了解决低温环境下弯管脆断的问题,满足我国长输油气管道低温站场用钢管的需求,针对油气输送用X80钢级直缝埋弧焊管焊接接头在回火热处理后,焊缝金属夏比冲击韧性存在明显回火变脆的现象,对多丝单道焊和单丝多道焊的直缝埋弧焊管焊接接头进行了焊后箱式炉热模拟研究,并选用整体热煨制方式,试制了感应加热弯管,进行了理化性能评价。结果显示,焊缝中细小的针状铁素体板条随回火温度升高而合并粗化,是导致焊缝低温韧性显著降低的原因;采用淬火+回火热处理方法,可有效抑制焊缝夏比冲击韧性随回火加热温度的递增而恶化的趋势;X80钢级Φ1 422 mm×33.8 mm单丝多道焊感应加热弯管母管经淬火+回火热处理后,完全满足－45 ℃低温条件下中俄东线低温管道工程设计要求。     

Investigation of energy dissipation and flow regime over various forms of stepped spillways

The efficient operation of reservoirs relies on the effective release of water during flooding, requiring a good understanding of spillways and their hydraulics. A series of experiments was conducted in a laboratory flume on a stepped spillway model with moderate slope (26.6°) for discharges up to 0.0121 m³/s. Using regular uniform horizontal steps of 5 cm height, then several new step configurations including inclined and horizontal curved steps with and without reflector blocks, the flow patterns were investigated. The energy losses over a horizontal stepped spillway were compared with those obtained in a number of similar, previous studies, and with the results obtained for the new step configurations. Good agreement was shown with previous results for horizontal steps, and the inclined and horizontal curved steps dissipated about twice as much energy as the horizontal steps. The results highlight the importance of considering a variety of step forms in spillway design where flows are unpredictable and energy dissipation is important.     

Elastic Modulus of 304 Stainless Steel Coating by Cold Gas Dynamic Spraying

 304 stainless steel coating was deposited on the IF steel substrate by cold gas dynamic spraying (CGDS), and the elastic modulus of the 304 stainless steel coating was studied. The elastic modulus of cold sprayed 304 stainless steel coating was measured using the three-point bend testing and the compound beam theory, and the other mechanic parameters (such as the equivalent flexural rigidity and the moment of inertia of area) of the coatings were also calculated using this compound beam theory. It is found that the calculated results using the above methods are accurate and reliable. The elastic modulus value of the cold sprayed 304 stainless steel coating is 1179×105 MPa, and it is slightly lower than the 304 stainless steel plate (about 2×105 MPa). It indicates that the elastic modulus of the cold sprayed coatings was quite different from the comparable bulk materials. The main reason is that the pores and other defects are existed in the coatings, and the elastic modulus of the coatings also depends on varies parameters such as the feed stock particle size, porosity, and processing parameters.     

水电站溢洪道泄槽温度场和温度应力有限元分析

通过3种方案：无寒潮、有寒潮无保护、有寒潮有保护情况,对某水电站溢洪道泄槽施工期温度场及温度应力进行了三维有限元仿真计算, 研究了寒潮对溢洪道泄槽的影响范围及寒潮引起的温度场和温度应力的分布规律,对比了无保护和有保护情况下典型点的温度应力及不同厚度泡沫板的保温效果,提出了避免产生表面裂缝的保护措施,为泄槽的工程施工提供参考依据。     

建模分析扭矩判定矿井提升机主轴弯曲变形

提升机主轴的设计应原则上保证承受工作过程中的外载荷而不发生残余变形和过量的弹性变形,所以分析出在实际工作过程中的承载状况—不合理承载或超载,可以及早预知提升机主轴的弯曲变形进而防止提前引起主轴断裂。利用实体建模分析扭矩的方法来分析判定矿井提升机主轴弯曲与变形的主要原因。     

埋弧焊管弯曲试验开裂原因分析

对埋弧焊管检验中出现的正弯和反弯不合格试样进行了金相分析,发现这些不合格试样均在焊缝焊趾处存在微裂纹或微咬边,这是导致弯曲开裂的主要原因。产生微裂纹的原因是焊缝与母材过渡不平滑,焊趾处应力集中过大,再加上矫平试样时未去除焊缝余高;产生微咬边的原因是焊接过程中焊接规范不恰当或焊接过程设备运行不稳定。     

A comparison of plastic collapse and limit loads for single mitred pipe bends under in-plane bending

This paper presents a comparison of the plastic collapse loads from experimental in-plane bending tests on three 90° single un-reinforced mitred pipe bends, with the results from various 3D solid finite element models. The bending load applied reduced the bend angle and in turn, the resulting cross-sectional ovalisation led to a recognised weakening mechanism. In addition, at maximum load there was a reversal in stiffness, characteristic of buckling. This reversal in stiffness was accompanied by significant ovalisation and plasticity at the mitre intersection. Both the weakening mechanism and the post-buckling behaviour are only observable by testing or by including large displacement effects in the plastic finite element solution. A small displacement limit solution with an elastic-perfectly plastic material model overestimated the collapse load by more than 40% and could not reproduce the buckling behaviour.     

泄洪兼导流洞布置型式与规模的分析确定

泄水建筑物是水利枢纽工程中泄水建筑物重要组成部分,不仅要承担枢纽施工期的导流泄水任务,还要承担枢纽运行期的泄洪、放空、排砂底孔等任务,在不同使用时期具有不同使用要求的工程特点。通过分析泄洪兼导流洞工程任务和特性,研究影响建筑物型式与规模的各种因素,以确定泄洪兼导流洞建筑物经济合理的型式与规模,结合工程设计实例进行分析论证。