薄板和三维体应变位移关系的二次完整表达式——兼评T.VonKármán方程

笔者给出了薄板和三维体应变位移关系的二次完整表达式 ,并对卡门薄板大挠度方程作了讨论     

带DA阀的液压泵功能分析及系统调试

为更好地使用和调试DA阀的泵控系统，确保DA控制系统在工程机械上运用的灵活性，做到不同工况设备都能自动处在最佳状态工作，通过分析DA阀和DA泵的构造原理及测试曲线，论证DA泵的3个主要功能： 1）发动机转速控制排量功能，即操纵发动机油门踏板就可以改变泵的排量，从而改变车速的自动驾驶功能； 2）恒功率功能，即通过调节并锁定泵的设定，使泵有稳定的功率输出，以适应原动机的功率； 3）压力切断功能，即当泵的压力达到设定的最大极限压力时，控制泵的排量接近为0，以防发动机因负载过大而熄火。通过对具体设备液压系统主要参数的设定和调试，给出DA泵系统的调试方法与调试过程，以实现DA泵转矩与发动机转矩的最佳匹配，减小发动机功率损耗和防止发动机因负载过大而熄火，同时也减轻操作者的疲劳和负担。     

畸变电源作用于二阶网络的研究

本文用大量实验数据和图片真实记录了畸变电源作用于二阶网络对电流冲击的影响,并通过计算给予了理论上的验证,同时还进一步分析计算了电流冲击与网络参数的关系.     

Land Changes and Conflicts Coordination in Coastal Urbanization: A Case Study of the Shandong Peninsula in China

The coastal zone is an interaction region between land and ocean and an interface of geosphere, hydrosphere, atmosphere, and biosphere, as well as greatly affected by human activities. Driven by economic activities and increased population, urbanization is rapidly developing in coastal zones, and a series of land resource and environmental conflicts have occurred, especially in developing countries at times of economic transition. This article reports a case study of the Shandong Peninsula of East China. We analyze the land-use practices and land cover changes of six cities over a timeframe of nearly a decade. We then review the management conflict issues. The most commonly encountered conflicts fall into three categories: those between expanding constructed land and decreased cultivated land; those between land resource utilization and conservation; and those between increasing demand for land and degrading land quality. All in all, they reflect the fundamental conflicts between short-term economic development gains and long-term food security and ecosystem sustainability. This article puts forward an institutional approach to coordinate these conflicts so as to realize integrated and coordinated coastal management.     

Bucket Group Effect of the Composite Multi-bucket Structure

As a novel type of foundation in beach and shallow sea,the bucket structure is especially suitable for complex conditionssuch as soft clay ground and the worse types of sea environments.In this paper, the bearing capacity of a multi-bucket structure isstudied by experiments with a single bucket and four-bucketfoundation in a saturated sand layer. Based on the experimentaldata and numerical analysis results, the bearing capacity behaviorand the bucket group effect are compared and analyzed.Furthermore, some influential factors, such as the soil type, theratio of length to diameter L/D, the ratio of the bucket spacing tothe bucket diameter S/D, and the bucket number are introduced andtheir effects on the multi-bucket structural capacity are investigatedThe vertical static capacity adjustment factor is introduced toevaluate the bucket group effects of the multi-bucket foundation.     

Recent research on welding distortion prediction in thin plate fabrication by means of elastic FE computation

Elastic FE simulation with inherent deformation and interface element is an ideal and practical computational approach for predicting welding distortion in production of thin plate structures. In this study, recent researches on inherent deformation theory and welding induced buckling investigation of ship panel were sequentially introduced. Taking bead-on-plate welding as research objective (plate with 2.28 mm in thickness), integration approach with inherent strain was proposed to accurately and conveniently evaluate magnitude of inherent deformation. Also, average temperature to clarify the mechanism of influential effect of plate width on magnitude of inherent deformation was presented and examined. With the mechanism investigation of welding induced buckling by elastic FE analysis using inherent deformation, an application for predicting and mitigating the welding induced buckling in fabrication of ship panel with thin plates by employing different welding procedure patterns was carried out. Examined intermittent zigzag welding procedure is effective to reduce the magnitude of in-plane inherent shrinkages and control the possible welding induced buckling.     

Prediction of hull girder moment-carrying capacity using kinematic displacement theory

The hull girder moment capacity of a very large crude oil carrier (VLCC) called Energy Concentration (EC), for which many benchmark studies have been carried out using the simple progressive collapse method (SPCM), is predicted. In this study, three approaches are used to represent the load-shortening behavior, so-called average compressive strength, of a stiffened panel, comprising the hull section: 1) kinematic displacement theory (KDT); 2) nonlinear finite element analysis (FEA); and 3) simple formulas in the common structural rule (CSR) for tankers. Load-shortening curves for various kinds of stiffened panels in EC are compared for five different scenarios with variations of load-shortening approaches and initial imperfections. In order to verify the effect of load-shortening on the prediction accuracy of the hull girder moment-carrying capacity, load-shortening curves are imported into an SPCM-based in-house program called Ultimate Moment Analysis of Damaged Ships (UMADS). Comparison of the hull girder ultimate strength for general heeling conditions, including hogging and sagging conditions, reveals that the load-shortening curves significantly affect the hull girder moment-carrying capacities. Based on our comparison of these capacities with other benchmark results, it is concluded that nonlinear FEA provided the most conservative results, KDT provided the second most conservative results, and the CSR formulas predicted the upper bound.     

MAP气调保鲜技术在现代船舶上的应用分析

通过对气调保鲜系统原理的分析,总结了MAP气调保鲜技术在陆上联调的经验,并对其中的关键技术进行阐述,为今后MAP气调保鲜技术在船舶上的推广奠定基础。     

充填粉土的大尺度土工织物充填袋参数分析

通过工程实例,得出粉土作为充填物的大尺度土工织物充填袋的各项参数,给出充填压应力与袋体周向拉力之 间的关系,并得出一定规格的土工织物充填袋的填筑流失率。通过分析地基沉降位移数据,在确保地基稳定的条件下,调 整了沉降位移控制标准,使施工效率得到提高,且缩短了施工工期,降低了施工成本。     

广州地铁暹岗站的抗浮计算分析

抗浮计算是地下地铁车站设计的重点,而计算参数、计算模型的选取对抗浮计算结果有较大影响。抗浮计算中部分参数的选取尚无统一规定,且使用阶段结构底板,尤其是轨道范围内的位移控制尚未引起足够重视。针对广州地铁暹岗站抗浮设计,选取适当的计算参数及公式,并采用有限元结构计算软件分析结构底板位移,最终合理确定结构相关抗浮方案。在满足抗浮的同时,车站底板不仅需要满足结构挠度要求,还需要考虑使用阶段的结构位移。可采用有限元计算软件进行模拟计算。