Types Of Support Structures Research Articles

Multivariate Data Analysis of Maximum Stress Concentration Factors in FRP-Retrofitted Two-Planar KT-Joints under Axial Loads for Offshore Renewables

With growing concerns about the danger of global climate change and worldwide demand for energy, the interest in the investigation and construction of renewable energy technologies has increased. Fixed platforms are a type of support structure for wind turbines composed of different types of tubular joints. These structures are under different kinds of cyclic loadings in ocean environmental conditions, which must be designed and reinforced against fatigue. In the present paper, the relationships between the parameters in DKT-joints reinforced with FRP under axial loads are investigated using several models, under 16 axial loading cases, with different nondimensional parameters and different FRP materials, and orientations were generated in ANSYS (total 5184) and analyzed. The four loading conditions that cause the maximum stress concentration factors were selected. After analyzing the 1296 reinforced models, relevant data were extracted, and possible samples were created. The extracted data were used in a multivariate data analysis of maximum stress concentration factors. The Pearson correlation coefficient is utilized to study the relationship between parameters and subsequently to make predictions. To reduce the number of variables and to group the data points into clusters based on certain similarities, hierarchical and non-hierarchical classifications are used, respectively.

Effect of support structure design toward residual stress of part build using selective laser melting

AbstractSelective laser melting process required post‐processing of support structure and it is compulsory to use it at overhanging part. There is certain condition where support structure cannot be remove using wire cut machine because of limited access to part and need to be remove manually. This is where the removability of support structure plays important role because support structure needed to be design so that it can be easily remove using manual way. In addition, when comparing contour type of support structure with the most commonly use block type of support structure it shows that contour type is easier to be remove. Furthermore, no research has been done on optimizing the contour type of support structure. A research experiment is conducted in this work to optimize the parameter of contour support structure which is contour offset, teeth height, teeth top length and teeth base length. The result indicates amount of residual stress and the time required for support removal are significantly influenced by contour offset, while all parameters are significant for support volume. The optimum parameter to get low residual stress is contour offset is 0.6 mm, teeth height is 1.4 mm, teeth top length is 0.75 mm and teeth base length is 1.55 mm.

The contribution of the bolting system to the shear stiffness of circumferential joints in tunnel segmental linings

The tunnel segmental lining is a type of support structure that is very complex and widely used in tunnel excavation. Of particular importance is the behaviour of circular joints in contact with adjacent rings.The shear behaviour of the circular joint is studied in detail in this paper. Particularly, bolts, which are widely used to connect the adjacent segments, play a fundamental role in the mechanical behaviour of the circular joints and therefore of the tunnel segmental lining.A new FEM model has been developed to be able to analyse the shear deformation of bolts, when two adjacent segments show a relative transversal displacement. The model allows to consider also the interaction of the bolt with the walls of the hole. It was possible to obtain the trend of the shear stiffness of the circular joint as the relative transversal displacements varied.A successfully comparison of the calculation results with the laboratory measurements was obtained. Some suggestions are proposed in order to enhancing the practicality of the model. The proposed numerical model is a useful calculation tool capable of correctly evaluating the mechanical behaviour of the circular joints and therefore to correctly represent them during the design stage.

Support design of overhanging structure for laser powder bed fusion

Warpage deformation inevitably occurs when laser powder bed fusion (LPBF) is applied on an overhanging structure. An effective support added to the system can mitigate warpage and improve the accuracy of formed parts. Four types of support structures are designed, and sheet tensile specimens and overhanging structures with different support structures are fabricated in this study. The tensile failure behavior and warpage suppression ability of different support structures are investigated, with the relation of the support influence to the design of support structure analyzed. The results show that the support with reinforcement can effectively restrain warpage deformation of the overhanging structure. During the process of tension, the main failure area of the support structure is located on the top of the support structure, close to the overhanging solid body. Increasing the change ratio of the support cross-sectional area is helpful to improve the constraint ability of the support. This design provides a new method for accurate forming of overhanging structures via LPBF and evaluating the restrain ability of support structures.

Numerical Simulation of Anchorage Force and Deformation of Pile in Deep Mixed Soil Foundation Pit

Foundation pit support plays a pivotal role in the process of urbanization in our country. The emergence of new support forms has dramatically enriched the diversity of foundation pit support. The pile-anchor support structure is a new type of support structure that has emerged with the development of foundation pit engineering in recent years. However, the current theoretical research on the foundation pit pile-anchor support system often cannot meet the improvement of the on-site construction technology level, and many calculation models based on assumptions cannot truly reflect the relationship between the foundation pit support structure and the soil layer, and the piles The stress and deformation characteristics of the anchor support system itself[1]. With the rapid economic development and the continuous expansion of the urban construction scale, the foundation pit problem caused by high-rise buildings and underground traffic has become a hot issue in civil engineering. Foundation pit accidents often occur due to design errors. 3D numerical simulation can better simulate the whole process of foundation pit excavation and support, and provide displacement and internal force prediction data for actual construction, thereby effectively preventing foundation pit accidents. Midas finite element software performs numerical simulation analysis of deep foundation pit support. Through further analysis of vertical deformation and horizontal displacement, the deformation value of the supporting structure is extracted and compared with the measured deformation value to guide the deformation control design and engineering monitor.

The Application of Pile Foundation Bearing-Retaining Wall Combination Structure in a Mountainous Urban High Fill Project

Pile foundation bearing-retaining wall combination structure is a new type of support structure developed in recent years. This article focuses on the characteristics, advantages, and application scope of the support structure, while combining a variety of algorithms, according to different geological conditions and slope stability, as well as summarizes the pile foundation bearing-retaining wall combination structure force analysis and design methods, taking a high-fill road project in Chongqing as an example. The application of this support structure under special conditions, such as thicker soil layer, steeper sliding surface, weak foundation, and limited slope release conditions, is presented, which illustrates the technical advantages of this support structure and proving that it has several other advantages, including clear force mechanism as well as economic and reasonable structure, thus providing reference for similar projects.

A surrogate model of offshore wind farm support structures for wind farm design and financial valuation

In the preliminary phases of offshore wind farm development, very little information on project design are available for supporting financial valuation and site design. In this work, we develop a surrogate model for offshore wind support structure mass for input to techno-economic analysis that is based on a small set of input parameters. Using reference turbines and a broad set of met-ocean conditions, a large design spaced is developed from which a sampling of conditions is used to estimate the dimensions and mass of monopile support structures. The results are parameterized using statistical methods to create a functional model of costs relative to high-level site and technical inputs. To preserve the transparency of the model input-output relationships, a statistical surrogate model is used based on quadratic functions of the inputs. Overall, the rated power and rotor diameter of the turbine has the greatest influence on the mass, followed by the specific power. The water depth was the next most important environmental parameter, followed by wave period. The full surrogate model captures 98.5% of the variance of the monopile mass as a function of the above inputs. We present results related to monopile foundations, but the methodology is flexible and can be applied also in the case of other types of support structures.

Collision Behavior Comparison of Offshore Wind Tower as Type of Support Structure

본 논문에서는 한국의 서남해상에 건설예정인 해상풍력발전타워의 지지구조물로 고려되고 있는 세발구조와 자켓구조의 선박충돌 거동을 비선형동적해석을 통하여 비교‧분석하였다. 이 구조물은 3MW용량의 풍력타워를 지지하기 위하여 설계되었다. 두 지지구조는 쉘요소를 이용하여 비선형 거동을 고려할 수 있도록 모델링하였고, 발전기를 포함하는 상부의 타워구조물은 탄성재료를 이용하여 보요소와 집중질량으로 모델링하였다. 전체 질량은 세발구조가 자켓구조에 비하여 약 1.66배 정도였다. 바지선과 상선을 충돌선박으로 선정하여 모델링하였다. 조수차의 조건을 고려하여 충돌선박의 충돌위치를 평균해수면의 상하로 3.5m변동하는 것으로 고려하였다. 또한 각 선박의 최소충돌속도(=2.6m/s)에서의 충돌에너지를 각각 4배까지 증가시키면서 충돌거동을 산정하였다. 해석결과 지지구조 충돌부위의 강성이 클수록 선박의 소성에너지 소산량이 상대적으로 증가하였다. 충돌조건에 따라 풍력타워의 변형은 진동에서 붕괴까지 발생하였다. 세발구조가 자켓구조에 비하여 큰 충돌저항력을 보였다. 이는 중앙부에 강성이 집중된 구조적 특성과 상대적으로 많은 강재의 사용량에 기인한 것으로 판단된다.

A new type of auxiliary structure for tunnel-surrounding rock support – composite cantilever support structure

Abstract. The deformation and damage mechanisms of tunnel-surrounding rock masses have always been a major problem in underground engineering, and studying these mechanisms plays an important role in preventing this kind of geological disaster. Against the background of the above project, in this paper, we propose a new type of support structure: a composite cantilever support structure. Studies involving the numerical calculation and application of this support structure are carried out, and the conducted investigation indicates that (1) for a relatively broken rock mass, the composite cantilever support structure can effectively restrain the deformation of the tunnel-surrounding rock mass, (2) through numerical calculation, the appropriate design parameters of the support structure are obtained, and (3) the design parameters and design structure of the composite cantilever support structure must be further studied and verified under complex geological conditions by engineering.

Mining Hazards to the Safety of Segment Lining for Tunnel Boring Machine Inclined Tunnels

The segment lining is a new type of support structure for mining tunnels. The disturbance of coal excavation leads to the deformation of segment lining and has great hazards to the safety of the tunnels. Based on the tunnel boring machine (TBM) inclined tunnels in Xinjie mine, the ultimate span L0 of the rock beam on the top slab of the coal seam was calculated according to the bending (tension) damage theory. A numerical model was built to simulate the bottom area of the inclined tunnels. During the coal mining, the additional displacements and additional stresses of the segment lining were analyzed, and then the safety factors of the support structure were calculated. Finally, the width of the coal pillar to protect the inclined tunnels was determined. The results showed that the ultimate span of the rock beam on the top of the coal seam is 31.7 m, the deformation of the inclined tunnel has a fish-belly shape, and the deformation leads to the increase of maximum axial force and bending moment. For the inclined tunnels in Xinjie coalmine, a total width of 91.3 m of coal pillar must be reserved to keep the safety factor of the structure higher than 2.0 and prevent the inclined tunnels from the mining hazards.

Development and challenges of support structures for offshore wind turbines

AbstractThe objective of this article is to provide an overview on the development of the offshore wind energy and the challenges regarding the support structures of wind turbines. Since this field is very broad, the focus of this paper is on four topics: The general development of offshore wind energy, the different design types, the verification of fatigue strength and a review of the approval procedure and new normative regulations. Hence, a summary of the development of the offshore wind energy including an outlook is provided. Further, the different design types of support structures are introduced. A central topic of this paper is the testing and verification of fatigue strength of the critical design details, particularly the connections. As the author is active in several committees, challenges, changes and innovations in approval procedures and standardization are also discussed. Finally, these topics are summarized and related to the importance of offshore wind energy for the energy transition.

Improvements in the fatigue design of support structures for offshore wind turbines

AbstractExtended keynote paper of Eurosteel 2021This article provides an overview of the various support structures for offshore wind turbines and addresses the challenges that arise for the different design variants. First of all, the existing types of support structures are explained and their benefits and shortcomings discussed. Following that, the focus is on material fatigue and its analysis, which is of great importance due to the cyclic loading on the structures. A central topic of this article is the experimental evaluation of fatigue strength using large‐scale test setups and state‐of‐the‐art measurement methods. Critical and complex design details such as welds for extremely thick plates, tubular joints, grouted connections, large HV bolts and ring flanges are investigated to improve methods of analysis. Further, the new series of German standards (DIN 18088) for support structures for wind energy turbines and platforms is addressed. Finally, these topics are summarized and the importance of offshore wind energy for the transition to cleaner energy is emphasized.

The influence of greenhouse support structures on ion flow field under overhead high voltage direct current lines

When an overhead high voltage direct current (HVDC) line is near a greenhouse, surface charges on the dielectric film distort the electric field nearby. Extensive experimental researches have been conducted regarding charge characteristics, and various algorithms have been proposed to calculate the ion flow field considering the charged film. However, existing studies do not consider the greenhouse support structures. In this paper, based on the ion flow field simulation with charged film, a more complete greenhouse model considering support structures is built. The support structures are treated as grounded conductors. Experimental results agree well with the calculations. Then, the influences of the frames and the wall (two typical types of support structures) are analyzed separately. The analysis considers the frame radius, position, and number, as well as the wall position and width. The total electric field is divided into three parts by charge sources, the effects of which are analyzed separately. The co-effect of the two kinds of support structures is also analyzed. The calculations show that the support structures, which are conductive and grounded, can effectively reduce the ground-level electric field. This research can predict the absolute value and help us understand the characteristics of the actual electric field near a greenhouse built under overhead HVDC lines.

Technology for Strengthening Earth Mound’s Foundations, Reinforced with Geosynthetic Materials

Technology of strengthening subgrade foundations, using geosynthetic material at a specific object is described in the article. The use of the proposed geosynthetic material as a reinforcing element is effective, creating load-bearing layers of the earth mound’s foundations, slopes or other types of support structures. Soil base reinforcement of the earth mound with geosynthetic woven material “Stabilenka®” allows increasing the bearing capacity of weak silty clay soils of soft plastic and fluid consistencies to fluid from 1.5 to 5 times, depending on the strength of the material, reduce deformability by 20% and can be considered as the most optimal. We can consider, that the use of a new progressive material allows increasing bearing capacity of the subgrade and reducing the cost and labor intensity of its construction in comparison with traditional methods and the duration of the mound preparation on weak areas is reduced by up to 5 times, using such technology.

Study on the Influence of Wall Spacing on Double Diaphragm Wall Supporting Structure for Ship Lock Expansion

Given China’s economic growth, current river ship locks in the Beijiang channel are reaching saturation. Ship lock expansion at key navigation terminals is imminent. This paper took Qingyuan’s new second-line ship lock in Guangdong, China as the engineering case, were a double diaphragm wall was utilized as the support scheme. Currently, there are very few engineering examples of this type of support structure both in China and abroad. Through the geotechnical finite element analysis software MIDAS GTS NX, a 3D finite element model was constructed to study the deformation and internal stresses of the support structure and adjacent ship lock, during the new ship lock’s foundation pit excavation, under different wall spacing. Based on the engineering case simulation results under different double diaphragm wall spacing, conclusions are reached on the influence and behaviour of the wall spacing double diaphragm wall structural parameter.

Design Optimization of Conical Concrete Support Structure for Offshore Wind Turbine

Various types of support structures for offshore wind turbine have been developed, and concrete structures have attracted attention due to many advantages. Although many studies have been conducted on the design of the existing steel structures, information and research on the design of concrete support structures are insufficient. Therefore, in this paper, a structural analysis model of conical concrete support structure (CCSS) is established and design optimization is presented. A detailed performance evaluation and the design of prestressed concrete were performed under the marine conditions of Phase 1 test site of southwest offshore wind project in Korea. The fluid–soil–structure interaction (FSI) was applied using the added mass method and soil spring model to represent the effects of water and soil. With the result of quasi-static analysis, a post-tensioning design was implemented by applying prestressing steel, and CCSS showed sufficient rigidity. From the natural frequency analysis, CCSS has a dynamic structural stability, and, in response spectrum and time-history analyses, the CCSS was safe enough under the earthquake loads. The methods and conclusions of this study can provide a theoretical reference for the structural analysis and design of concrete support structures for offshore wind turbines.

A novel method to improve the removability of cone support structures in selective laser melting of 316L stainless steel

In selective laser melting (SLM), support structures play a critical role in successful printing. Despite its necessity, the removal of support structures after printing becomes a challenging task which is usually time-consuming and labour-intensive. Mechanical post-processing can be employed to facilitate the automatic removal of support structures with higher efficiency. However, the mechanical forces of a machining process such as milling can cause the cone supports to tilt, collapse and be pulled up. This paper presents a novel method to improve the machinability of cone support structures. In this method, the epoxy resin is filled into the gaps between the entire cone support structures to form a solid composite structure after the epoxy resin is fully cured. The relationship between the force components in various directions during support removal is theoretically analyzed. The method is studied in terms of cutting performance, cutting force and energy, tool wear, workpiece surface damage and corrosion behaviour. On top of rectifying the problems of resultant support tilting and collapsing, the cutting force, specific cutting energy, tool wear and damage to the workpiece surface are significantly reduced, and the corrosion behaviour of the samples is slightly improved due to better surface quality after support removal. A finite element model is constructed for analysis of the underlying mechanisms. This paper addresses the research gap on the corrosion behaviour of the workpiece after support removal, and the newly developed method can be further applied to the machining of other types of support structures in SLM.

Stability Analysis of the Floating Offshore Wind Turbine Support Structure of Cell Spar Type during its Installation

Abstract The article presents the results of selected works related to the wider subject of the research conducted at the Faculty of Ocean Engineering and Ship Technology of the Gdansk University of Technology, which concerns design and technology of construction, towing, and settlement on the seabed, or anchoring, of supporting structures for offshore wind farms. As a result of this research, several designs of this type of objects were developed, including two stationary types: gravitational and Jack-up, which are placed on the seabed, and two floating types: TLP and SPAR, anchored with tendons and anchors in the form of nailed or suction piles. Below presented is the stability analysis of the new floating CELL SPAR type support structure for offshore wind turbines during its installation in waters with a depth of over 65 m.

The effect of support structure on RANS actuator disc for shallow water application

The effect of support structure on the wake formation of the tidal turbine needs to be considered when investing in a tidal energy farm. The wake resulted from the support structure may vary with the array of turbine. There is various type of support structure that are under development and each type of the support structure exhibit a different behaviour of the wakes.. Four types of geometry of the support structure such as cylinder, ellipse, square and diamond were analyzed using Computational Fluid Dynamic (CFD). The k-epsilon turbulence model was used to analyze the effects of the support structure. From this study, the flow of turbulence on each support structure exhibits different behaviour. For a single turbine, it was found that ellipse geometry of the support structure indicates the shortest turbulence form. However, in terms of velocity deficit the diamond geometry illustrates the highest value followed by the square, cylinder and ellipse geometry. For the array configuration, it proves that the 1.5D for distances between two turbines is acceptable since turbulence occurrence is separated from each of the turbine. In addition, for three turbines arrangement, the separation between the first and second rows is agreeable on 3D because the wakes are well merged and almost return to ambient condition at 1D downstream. Based on the results of this research it can be concluded that ellipse support structure shows promising results due to the wake formation recovers back to the inlet velocity the fastest among the other support structure when passing through the tidal turbine.

Seismic Response Comparison of Offshore Wind Turbines as Types of Support Structures

Seismic Response Comparison of Offshore Wind Turbines as Types of Support Structures