scholarly journals Numerical Analysis of the Deformation Performance of Monopile under Wave and Current Load

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6431
Author(s):  
Libo Chen ◽  
Xiaoyan Yang ◽  
Lichen Li ◽  
Wenbing Wu ◽  
M. Hesham El Naggar ◽  
...  
Keyword(s):  
Finite Element ◽  
Deformation Mechanism ◽  
Large Diameter ◽  
Offshore Wind ◽  
Stokes Wave ◽  
Reverse Direction ◽  
Design Parameters ◽  
Embedment Depth ◽  
Current Load ◽  
Maximum Displacement

The research on the deformation mechanism of monopile foundation supporting offshore wind turbines is significant to optimize the design of a monopile foundation under wave and current load. In this paper, a three-dimensional wave-pile-soil coupling finite element model is proposed to investigate the deformation mechanism of monopile undercurrent and fifth-order Stokes wave. Different from the conventional assumption that there is no slip at the pile-soil interface, Frictional contact is set to simulate the relative movement between monopile and soil. Numerical results indicate that under extreme environmental conditions, the monopile foundation sways within a certain range and the maximum displacement in the loading direction is 1.3 times the displacement in the reverse direction. A further investigation has been made for a large-diameter pipe pile with various design parameters. The finite element analyses reveal that the most efficient way to reduce the deflection of the pile head is by increasing the embedment depth of the monopile. When the embedment depth is limited, increasing the pile diameter is a more effective way to strengthen the foundation than increasing the wall thickness.

scholarly journals MODELING THE WORK OF THE HEAD OF A HYDROMECHANICAL EXPANDER FOR WELDED PIPES OF A LARGE DIAMETER

2020 ◽  
pp. 35-42
Author(s):  
L. M. Gurevich ◽  
V. F. Danenko ◽  
A. A. Istrati ◽  
V. A. Sonnova
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Internal Pressure ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Welded Joint ◽  
Large Diameter ◽  
Design Parameters ◽  
Maximum Stresses ◽  
Distribution Of Stresses

Finite element simulates of changing stresses and strains under loading by gradually increasing internal pressure of cylindrical welded vessels was carried out. The vessels had an annular mechanically inhomogeneous welded joint with different mechanical properties of the joint, heat-affected zone, and base metal. Maximum stresses developed in the caps of the vessels, and the annular joint are lightly loaded. The distribution of stresses and strains in joint at various design parameters of the vessels is investigated.

The Design and Optimization of Large-Scales Heavy Gantry NC Machining Center Based on Finite Element Method

2011 ◽  
Vol 697-698 ◽  
pp. 656-660
Author(s):  
Shu Bo Xu ◽  
K.K. Sun ◽  
Cai Nian Jing ◽  
Guo Cheng Ren
Keyword(s):  
Finite Element ◽  
Contact Point ◽  
Large Diameter ◽  
Cnc Machining ◽  
Beam Structure ◽  
Maximum Displacement ◽  
Design And Optimization ◽  
Contact Points ◽  
Machining Center ◽  
Maximal Displacement

Large gantry machining center can be applied to large diameter and thickness of the flanges, tube sheets and other large sheet metal processing, the industrialization of this type of device for improving the development of modern processing and manufacturing of great strategic significance. The design and optimization of large-scales heavy gantry CNC Machining Center was mainly investigated in this paper. The finite element model of the beam structure was structured by using finite element analysis software-ANSYS. On the basis of analysis results, the optimal static and dynamic performance of square cross-section of the beam structure has been obtained. The maximal displacement is 0.531 mm. The maximum displacement of X=0.0329mm, and Y=0.531 mm occurred in the contact point of middle beam and spindle box. Z is 0.0948mm. The maximal displacement of Y-component is occurred in the contact points of guide and spindle box. This may have a certain impact on the machine processing accuracy. In the middle of the beam can consider to strengthen its internal structure, such as adding reinforcement measures to further improve its rigidity, and improve the machining precision of the whole machine.

Finite Element Analysis of Large Diameter Grouted Connections

2007 ◽  
Author(s):  
Lars P. Nielsen
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Wind Turbine ◽  
Large Diameter ◽  
Wind Farms ◽  
Element Model ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Joint Research ◽  
Element Analysis

When considering offshore monopile foundations designed for wind turbine support structures, a grouted connection between the monopile and an overlapping transition piece has become the de facto standard. These connections rely on axial loads being carried primarily by the bond between the steel and grout as shear. Given the critical nature of the grouted connection in a system with zero redundancy, the current design verification requirement is that a finite element analysis is performed to ascertain the viability of the connection with respect to combined axial and bending capacity whilst pure axial capacity is handled as a decoupled phenomenon using simple analytical formulas. The present paper addresses the practical modeling aspects of such a finite element model, covering subjects such as constitutive formulations for the grout, mesh density, and steel/grout interaction. The aim of the paper is to discuss different modeling approaches and, to the extent possible, provide basic guidelines for the minimum requirements valid for this type of analysis. This discussion is based on the accumulated experience gained though the independent verification of more than 10 currently operational offshore wind farms that have been certified by DNV, as well as the significant joint research and development with industry captured in the DNV Offshore Standard for Design of Offshore Wind Turbine Structures DNV-OS-J101. Moreover, general observations relating to the basic subjects such as overall geometric extent of the model, inclusion of secondary structures, detail simplification, boundary conditions, load application etc. are presented based on the authors more than 3 year involvement on the subject at DNV.

scholarly journals Reliability Based Analysis and Design of a Tripod Offshore Wind Turbine Structure Assuring Serviceability Performance

2018 ◽  
Vol 25 (4) ◽  
pp. 139-148
Author(s):  
Jianhua Zhang ◽  
Won-Hee Kang ◽  
Chunwei Zhang ◽  
Ke Sun
Keyword(s):  
Structural Design ◽  
Computational Models ◽  
Rank Order ◽  
Offshore Wind ◽  
Design Parameters ◽  
Offshore Wind Turbine ◽  
Preliminary Design ◽  
Maximum Displacement ◽  
Maximum Deformation ◽  
Analysis And Design

Abstract Typical tripod foundations are designed using deterministic computational models according to relevant standards and codes. However, for more cost-safety balanced design, uncertainties in significant parameters should be considered in preliminary design to ensure meeting a specific probabilistic safety target in the context of the complex configuration of a tripod structure. In this article, uncertainties associated with design parameters and modelling errors are considered using Monte Carlo simulations, in order to determine the key structural design parameters, and to determine the optimal balance between design parameters and design requirements. A Spearman rank-order correlation based analysis is carried out to understand the effects of design variables on maximum deformation, total weight, and natural frequency, and to have insight about important design parameters for improvement of a preliminary design. It is found that the tower diameter has the most significant effect on the maximum displacement on the hub as validated through engineering case studies. In addition, a statistical framework, which identifies influential design parameters and provides reliability evaluation, is proposed for the structural design of a tripod OWT system. The design cases considered in this study indicate that a simple deterministic design check cannot guarantee the required reliability level of the structure, and the cost-safety balance can be achieved by a reliability analysis with the consideration of the uncertainties in the structure.

Finite Element Modeling of Large Diameter Monopiles in Dense Sand for Offshore Wind Turbine Foundations

2015 ◽  
Author(s):  
Sheikh Sharif Ahmed ◽  
Bipul Hawlader ◽  
Kshama Roy
Keyword(s):  
Finite Element ◽  
Wind Turbine ◽  
Large Diameter ◽  
Three Dimensional ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Physical Model Test ◽  
Arbitrary Lagrangian Eulerian ◽  
Dense Sand ◽  
Strain Behavior

With increasing demand of energy, attention to the alternative sources of sustainable energy is getting priority over the last decades. Offshore wind turbine is one of them. The most widely used foundation system for the wind turbine is the monopile, which is a large diameter single pile. In the present study, three-dimensional finite element (FE) analyses are performed to evaluate the capacity of large diameter monopiles in dense sand using the Arbitrary Lagrangian-Eulerian (ALE) approach available in Abaqus/Explicit FE software. The behavior of sand is modeled using the Mohr-Coulomb (MC) and a modified Mohr-Coulomb (MMC) model where the pre-peak hardening, post-peak softening and the effects of mean effective stress and relative density on stress-strain behavior of dense sand are considered. Comparison with physical model test results shows that the MMC model can simulate better the load-displacement response than that with the MC model. The mechanisms involved in soil deformation are also explained using FE results.

Establishing and Satisfying Thermal Requirements for Drilled Shaft Concrete Based on Durability Considerations

2021 ◽  
pp. 036119812199635
Author(s):  
Andrew Z. Boeckmann ◽  
Zakaria El-tayash ◽  
J. Erik Loehr
Keyword(s):  
Mechanical Response ◽  
Large Diameter ◽  
Thermal Cracking ◽  
Drilled Shafts ◽  
Maximum Temperature ◽  
Design Parameters ◽  
Mass Concrete ◽  
Temperature Differential ◽  
Thermal Requirements ◽  
Ettringite Formation

Some U.S. transportation agencies have recently applied mass concrete provisions to drilled shafts, imposing limits on maximum temperatures and maximum temperature differentials. On one hand, temperatures commonly observed in large-diameter drilled shafts have been observed to cause delayed ettringite formation (DEF) and thermal cracking in above-ground concrete elements. On the other, the reinforcement and confinement unique to drilled shafts should provide resistance to thermal cracking, and the provisions that have been applied are based on dated practices for above-ground concrete. This paper establishes a rational procedure for design of drilled shafts for durability requirements in response to hydration temperatures, which addresses both DEF and thermal cracking. DEF is addressed through maximum temperature differential limitations that are based on concrete mix design parameters. Thermal cracking is addressed through calculations that explicitly consider the thermo-mechanical response of concrete for predicted temperatures. Results from application of the procedure indicate consideration of DEF and thermal cracking potential for drilled shafts is prudent, but provisions that have been applied to date are overly restrictive in many circumstances, particularly the commonly adopted 35°F maximum temperature differential provision.

scholarly journals Reliability Evaluation of Fan-Out Type 3D Packaging-On-Packaging

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 295
Author(s):  
Pao-Hsiung Wang ◽  
Yu-Wei Huang ◽  
Kuo-Ning Chiang
Keyword(s):  
Finite Element ◽  
Thermal Cycling ◽  
Glass Substrate ◽  
High Speed ◽  
Coefficient Of Thermal Expansion ◽  
Three Dimensional ◽  
Design Parameters ◽  
Time To Failure ◽  
Wafer Level ◽  
Fine Pitch

The development of fan-out packaging technology for fine-pitch and high-pin-count applications is a hot topic in semiconductor research. To reduce the package footprint and improve system performance, many applications have adopted packaging-on-packaging (PoP) architecture. Given its inherent characteristics, glass is a good material for high-speed transmission applications. Therefore, this study proposes a fan-out wafer-level packaging (FO-WLP) with glass substrate-type PoP. The reliability life of the proposed FO-WLP was evaluated under thermal cycling conditions through finite element simulations and empirical calculations. Considering the simulation processing time and consistency with the experimentally obtained mean time to failure (MTTF) of the packaging, both two- and three-dimensional finite element models were developed with appropriate mechanical theories, and were verified to have similar MTTFs. Next, the FO-WLP structure was optimized by simulating various design parameters. The coefficient of thermal expansion of the glass substrate exerted the strongest effect on the reliability life under thermal cycling loading. In addition, the upper and lower pad thicknesses and the buffer layer thickness significantly affected the reliability life of both the FO-WLP and the FO-WLP-type PoP.

Finite Element Analysis on the Deformation of Energy-Saving Wire-Mesh Frame Wallboard

2014 ◽  
Vol 501-504 ◽  
pp. 731-735
Author(s):  
Li Zhang ◽  
Kang Li
Keyword(s):  
Finite Element ◽  
Energy Saving ◽  
Theoretical Basis ◽  
Steel Wire ◽  
Wire Mesh ◽  
Design Parameters ◽  
Element Analysis ◽  
Finite Element Program ◽  
Element Program ◽  
Influence Degree

This paper analyzes the influence degree of related design parameters of wire-mesh frame wallboard on deformation through finite element program, providing theoretical basis for the design and test of steel wire rack energy-saving wallboard.

Sign in / Sign up

Export Citation Format

Share Document