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This paper proposes an enhanced approach for evaluating the fatigue life of each metallic layer of unbonded flexible risers. Owing to the complex structure of unbonded flexible risers and the nonlinearity of the system, particularly in the critical touchdown zone, the traditional method is insufficient for accurately evaluating the fatigue life of these risers. The main challenge lies in the transposition from global to local analyses, which is a key stage for the fatigue analysis of flexible pipes owing to their complex structure. The new enhanced approach derives a multi-layer stress-decomposition method to meet this challenge. In this study, a numerical model validated experimentally is used to demonstrate the accuracy of the stress-decomposition method. And a numerical case is studied to validate the proposed approach. The results demonstrate that the multi-layer stress-decomposition method is accurate, and the fatigue lives of the metallic layers predicted by the enhanced multi-layer analysis approach are rational. The proposed fatigue-analysis approach provides a practical and reasonable method for predicting fatigue life in the design of unbonded flexible risers. 相似文献
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山东省苍峄地区铁矿资源丰富,是典型的"鞍山式"铁矿成矿区。先后发现和评价了多处大中型铁矿床。该文在介绍苍峄铁矿带成矿地质特征基础上,将其分为5个含矿带,矿体赋存于泰山岩群山草峪组中上部,严格受山草峪组地层控制,展布形态受太白向斜和石闫背斜两褶皱构造的控制,断层构造破坏了赋矿构造及矿体的连续性,间接控制了铁矿体的赋存和分布。原岩建造为基性火山岩-中酸性火山岩-粉砂岩-硅铁质建造,属火山活动间歇期成矿。分析认为成矿物质来源与海底火山活动密切相关,遭受后期变质作用后成矿物质富集,为沉积变质铁矿床产于以黑云变粒岩为主并夹有角闪质岩石等岩层的铁矿,铁矿沉积后,受后期强烈构造-热液改造叠加,矿体形态以似层状、透镜状为主。向斜构造是矿体富集保存的最佳构造模式,接近向斜核部矿体厚度增大,品位也有增高趋势。 相似文献
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青海省都兰县瑙木浑沟口金矿区位于昆中构造带北侧,区内断裂构造十分发育,金矿成矿条件优越。运用激电中梯测量,基本查明了区内与金成矿有关的断裂构造的分布情况,圈定激电异常2处,并施工探槽工程、硐探工程进行异常查证,证实物探异常为构造破碎带内硫化物富集体引起的,金矿化体与异常峰值对应基本吻合,最终发现了一处隐伏金矿床,说明物探异常在寻找隐伏金矿体的找矿工作中获得了很好的找矿效果。结合构造因素、物探异常及已有成矿事实综合分析,认为该区有较好的找矿前景。 相似文献
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This paper proposes an enhanced approach for evaluating the fatigue life of each metallic layer of unbonded flexible risers. Owing to the complex structure of unbonded flexible risers and the nonlinearity of the system, particularly in the critical touchdown zone, the traditional method is insufficient for accurately evaluating the fatigue life of these risers. The main challenge lies in the transposition from global to local analyses, which is a key stage for the fatigue analysis of flexible pipes owing to their complex structure. The new enhanced approach derives a multi-layer stress-decomposition method to meet this challenge. In this study, a numerical model validated experimentally is used to demonstrate the accuracy of the stress-decomposition method. And a numerical case is studied to validate the proposed approach. The results demonstrate that the multi-layer stress-decomposition method is accurate, and the fatigue lives of the metallic layers predicted by the enhanced multi-layer analysis approach are rational. The proposed fatigue-analysis approach provides a practical and reasonable method for predicting fatigue life in the design of unbonded flexible risers. 相似文献
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青海省那陵格勒河中游地区位于秦—祁—昆成矿域东昆仑成矿省祁漫塔格—都兰华力西期铁、钴、铜、铅、锌、锡、硅灰石(锑、铋)成矿带,该区及其周边已发现金属矿床(点)几十处,具有良好的金、铁、铅、锌、铜、镍矿找矿前景。本研究基于对该区水系沉积物样品新测试获取的20种元素,统计分析元素分布与特征参数,由此总结富集离散规律、元素组合特征及其与成矿地质条件的关系。研究结果显示：白沙河(岩)组中Pb、Bi、Zn明显富集,成矿指数较高,滩间山群中显著富集Cu、Cr、Ni、Co、V,印支期中酸性高温岩浆活动可以为地层中Cu、Pb、Zn等金属元素的活化提供充足的热动力。地层与印支期中酸性岩浆接触交代形成的矽卡岩带,可作为寻找矽卡岩型Cu、Pb、Zn多金属矿床的有利部位。结合成矿地质条件和地球化学特征,总计圈定了39处地球化学综合异常,并划分出5处找矿远景区,其中野马泉—牛苦头—黑山铜、金、锑与克提哈尔—红卫山铜、钴、镍、钒多金属成矿远景区可作为区内重点的铜多金属成矿远景带,具有较大的成矿潜力。本研究为区域多种有色金属矿产靶区优选、资源潜力评价和下一步地质找矿工作提供了参考。 相似文献
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青海省都兰县丘吉东沟银铅矿位于昆中断裂带内,区内断裂构造十分发育,主要为NW向断裂,与区域构造方向基本一致。区内含矿蚀变带与NW向深大断裂关系密切,NW向断裂为区内的主要的导矿、控矿构造,次级构造或构造膨胀部位及构造拐弯处,均为找矿的有利地段,可作为容矿场所。区内华力西期岩浆活动强烈,该期活动为区内岩浆活动的最高潮,是主要成矿期。研究区圈定2个矿带9条银铅矿体,呈脉状或透镜状赋存于蚀变硅质白云岩之NW向构造破碎带F_8,F_9内,是以银为主的多金属矿体。其中I-5矿体为主矿体,平均厚度2.38m,银平均品位216.87×10~(-6),铅平均品位1.98%,主要矿化蚀变为方铅矿化、黄铁矿化、黄钾铁钒化等。本文分析了丘吉东沟银铅矿地质背景、矿床地质特征等,总结了找矿标志,预测了找矿方向,以期为类似地区的银铅找矿工作提供借鉴经验。 相似文献
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随着陆上资源的日渐枯竭,深海开发已经成为世界主要大国的重要战略目标,实现高效、低能耗的深海矿产提升具有重要意义。基于大颗粒垂直管道提升理论和离心泵理论,针对不同矿浆浓度设定多种工况,假定泵级数,分别求解系统工作点。从效率、产量、功率和单位产量能耗四个优化指标出发,借助图像进行直观分析比较,优化泵级数的设置。分析结果表明,单位产量能耗在某一较高泵级数处可取得最小值,此时亦可保证较高的产量和泥泵效率较好的发挥,该泵级数可选取为最优泵级数方案。 相似文献
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