耐压柱壳参数化设计与灵敏度分析     

刘峰  王贺  苗怡然  屠超华  赵彦凯 《海洋技术学报》2019,38(1)

为提高耐压柱壳设计效率,设计了耐压柱壳参数化分析流程。研究了有限元分析所涉及的材料属性、载荷施加、边界条件设置等内容,确定了采用弧长法分析耐压柱壳稳定性。利用Python语言对于ABAQUS软件进行了二次开发,利用Isight软件实现了ABAQUS的集成,实现了耐压柱壳有限元分析模型的网格自动划分、自动分析计算等。选择样本点进行参数化分析,利用响应面模型对于样本点进行了拟合,得到了具有较高拟合精度、满足工程需要的近似模型,进行了设计变量的灵敏度分析。研究结果表明:参数化分析流程可实现耐压柱壳的自动分析、近似模型及灵敏度分析,可降低耐压柱壳分析难度,均可提高耐压柱壳设计效率。  相似文献   

地图审核在线审批系统分析与设计     

白敬辉 《测绘通报》2019,(7):109-113

随着互联网技术的发展和“互联网＋”业态的兴起，电子政务成为推进审批服务便民化的重要内容。地图审核作为一项行政许可，主要分为申请和受理、技术审查、审批和送达及样本备案4个业务环节。根据上述业务步骤，本文对地图审核在线审批系统的设计进行了分析，完成了系统的构建与应用，为同类型其他系统的构建提供了参考。  相似文献   

兼顾志愿者地理信息的国家应急测绘公众服务平台设计     

杨靓  黄蔚  查祝华  张红平 《测绘通报》2019,(9):147-151

随着互联网技术的进步和新一代网络信息传播模式的深入发展，志愿者地理信息的研究和应用日益广泛，但由于其规范性和均一性方面的缺陷，在应急公共服务领域，志愿者信息的有效利用依旧是亟需突破的难题。本文将重点介绍国家应急测绘公众服务平台设计思路和总体架构，并结合志愿者地理信息特点，探讨该类信息在国家应急测绘公众服务平台建设中的处理流程和应用模式，力求在应急信息资源共享和服务平台共建方面进行新的尝试，为我国突发事件应急体系建设提供有益实践。  相似文献   

A literature synthesis of LiDAR applications in transportation: feature extraction and geometric assessments of highways     

Suliman A. Gargoum  Karim El Basyouny 《地理信息系统科学与遥感》2019,56(6):864-893

Interest in using Light Detection and Ranging (LiDAR) technology in Transportation Engineering has grown over the past decade. The high accuracy of LiDAR datasets and the efficiency by which they can be collected has led many transportation agencies to consider mobile LiDAR as an alternative to conventional tools when surveying roadway infrastructure. Nonetheless, extracting semantic information from LiDAR datasets can be extremely challenging. Although extracting roadway features from LiDAR has been considered in previous research, the extraction of some features has received more attention than others. In fact, for some roadway design elements, attempts to extract those elements from LiDAR have been extremely scarce. To document the research that has been done in this area, this paper conducts a thorough review of existing studies while also highlighting areas where more research is required. Unlike previous research, this paper includes a thorough review of the previous attempts at data extraction from LiDAR while summarizing the detailed steps of the extraction procedure proposed in each study. Moreover, the paper also identifies common tools and techniques used to extract information from LiDAR for transportation applications. The paper also highlights common limitations in existing algorithms that could be improved in future research. This paper represents a valuable resource for researchers and practitioners interested in knowing the current state of research on the applications of LiDAR in the field of Transportation Engineering while also understanding the opportunities and challenges that lie ahead.  相似文献   

Cartographic Design and the Space–Time Cube     

Irma Kveladze  Menno-Jan Kraak  Corné P.J.M. van Elzakker 《The Cartographic journal》2019,56(1):73-90

This paper reports on the results of an empirical evaluation that aimed to define the effectiveness and efficiency of different visual variables in depicting the Space–Time Cube’s (STC) content. Existing STC applications demonstrate that the most used visual variables are size and colour hue. Less is known, however, about their usability metrics. The research sets design criteria for STC contents, such as space–time paths, based on the cartographic design theory. The visual variables colour hue, colour value, colour saturation, size and orientation have been applied in two different use case studies. Besides, to support the three-dimensional visual environment, depth cues such as shading and transparency were considered too. User tests have been executed based on real-world problems with particular attention for the visualization strategy and data complexity. The outcomes revealed the most efficient and effective visual variables to represent data of various complexities in the STC.  相似文献   

Cartographic Symbol Design Considerations for the Space–Time Cube     

Christopher League 《The Cartographic journal》2019,56(2):117-133

The cartographic representation of geographic phenomena in the space–time cube comes with special challenges and opportunities when compared with two-dimensional maps. While the added dimension allows the display of attributes that vary with time, it is difficult to display rapidly varying temporal data given the limited display height. In this study, we adapt 2D cyclic point symbols to construct 3D surfaces designed along a helical path for the space–time cube. We demonstrate how these complex?3D helical surfaces can display detailed data, including data reported daily over 100 years and data reported in four-hour intervals over a year. To create the point symbols, each value is plotted along the curve of a helix, with each turn of the helix representing one year or week, respectively. The model is modified by varying the radii from the time axis to all points using the attribute value, in these cases maximum daily temperature and four-hourly ridership, and then creating a triangulated surface from the resulting points. Using techniques common to terrain representation, we apply hue and saturation to the surface based on attribute values, and lightness based on relief shading. Multiple surfaces can be displayed in a space–time cube with a consistent time interval facing the viewer, and the surfaces or viewer perspective can be rotated to display synchronized variations. We see this method as one example of how cartographic design can refine or enhance operations in the space–time cube.  相似文献   

Reliability based assessment of axial pile bearing capacity: static analysis,SPT and CPT-based methods     

Sara Heidarie Golafzani  Abolfazl Eslami 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2020,14(3):216-230

ABSTRACT

Since piles are one of the major geotechnical foundation systems, estimation of their axial bearing capacity is of great importance. Employing different design methods, resulting in a wide range of bearing capacity estimations, complicates the selection of an appropriate design scheme and confirms the existence of model error along with the inherent soil variability in bearing capacity prediction. This paper tends to evaluate different predictive methods in Reliability-Based Design (RBD) framework. In this regard, different static analyses, SPT and CPT-based methods are considered to evaluate which approaches collectively and which method individually, have more reliable predictions for compiled data bank. In order to assess reliability indices and resistance factors, two approaches have been considered, i.e. First Order Second Moment method (FOSM) and First Order Reliability Method (FORM). To investigate the reliability indices for different methods in both RBD approaches, various safety factors and loading ratios have been considered. Also, the Load and Resistance Factor Design (LRFD) resistance factors are calibrated for different target reliability indices and loading ratios. Results show that CPT-based methods are more reliable among other methods. Furthermore, the estimated efficiency ratio, i.e. the ratio of resistance factor to resistance bias factor, confirms this agreement.  相似文献   

Advances in pan‐European flood hazard mapping          下载免费PDF全文

Lorenzo Alfieri  Peter Salamon  Alessandra Bianchi  Jeffrey Neal  Paul Bates  Luc Feyen 《水文研究》2014,28(13):4067-4077

Flood hazard maps at trans‐national scale have potential for a large number of applications ranging from climate change studies, reinsurance products, aid to emergency operations for major flood crisis, among others. However, at continental scales, only few products are available, due to the difficulty of retrieving large consistent data sets. Moreover, these are produced at relatively coarse grid resolution, which limits their applications to qualitative assessments. At finer resolution, maps are often limited to country boundaries, due to limited data sharing at trans‐national level. The creation of a European flood hazard map would currently imply a collection of scattered regional maps, often lacking mutual consistency due to the variety of adopted approaches and quality of the underlying input data. In this work, we derive a pan‐European flood hazard map at 100 m resolution. The proposed approach is based on expanding a literature cascade model through a physically based approach. A combination of distributed hydrological and hydraulic models was set up for the European domain. Then, an observed meteorological data set is used to derive a long‐term streamflow simulation and subsequently coherent design flood hydrographs for a return period of 100 years along the pan‐European river network. Flood hydrographs are used to simulate areas at risk of flooding and output maps are merged into a pan‐European flood hazard map. The quality of this map is evaluated for selected areas in Germany and United Kingdom against national/regional hazard maps. Despite inherent limitations and model resolution issues, simulated maps are in good agreement with reference maps (hit rate between 59% and 78%, critical success index between 43% and 65%), suggesting strong potential for a number of applications at the European scale. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Winkler model for dynamic response of composite caisson–piles foundations: Seismic response     

《Soil Dynamics and Earthquake Engineering》2014

A simplified method with a dynamic Winkler model to study the seismic response of composite caisson–piles foundations (CCPF¹) is developed. Firstly, with the dynamic Winkler model, the kinematic response of the CCPF subjected to vertically propagating seismic S-wave is analyzed by coupling the responses of caisson part and pile part. Secondly, a simplified model for the foundation–structure system is created with the structure simplified as a lumped mass connected to the foundation with an elastic column, and through the Fast Fourier Transformation (FFT) this model is enabled to solve transient seismic problems. Thirdly, the proposed method for the seismic response of CCPF-structure systems is verified by comparison against 3D dynamic finite element simulation, in which the Domain Reduction Method (DRM²) is utilized. Lastly, the mechanism and significance of adding piles in improving the earthquake resistance of the foundation and structure is analyzed through an example with different soil conditions. Discovered in this study is that adding piles under the caisson is an efficient way to increase seismic resistant capability of the soil–foundation–structure system, and the main mechanism of that is the elimination of the pseudo-resonance.  相似文献   

无隔水管泥浆回收钻井技术控制系统功能设计          下载免费PDF全文

陈浩文  刘晓林  王林清  于彦江  田烈余  王偲  殷国乐 《探矿工程》2021,48(S1):375-380

无隔水管泥浆回收钻井技术（RMR）作为双梯度钻井工艺之一,具有绿色环保、井身结构简易、工程成本低和安全程度高等优点。但是RMR作为新兴钻井工艺,虽然国外应用较为成熟,但国内目前尚无工程应用,缺乏相关使用经验。最关键的是RMR控制系统功能复杂,对可靠性、准确性及灵敏性等要求高,面对复杂工况时,要求控制系统能够及时准确的做出应对处理。因此,为发展国内无隔水管泥浆回收钻井技术（RMR）,拉近甚至超越国外钻井工艺水平,迫切需要对控制系统做出相对完善的设计。本文针对无隔水管泥浆回收钻井过程中的几类典型工况,分析不同工况下控制系统所具备的功能,设计控制功能具体的实现形式。通过对无隔水管泥浆回收钻井技术控制系统的功能设计与实现的研究,以期为今后同类研究提供有益的借鉴。  相似文献