Analysis of anchor foundation with root caissons loaded in nonhomogeneous soils

2011 ◽  
Vol 48 (2) ◽  
pp. 234-246 ◽  
Author(s):  
Maosong Huang ◽  
Chenrong Zhang ◽  
Linlong Mu ◽  
Weiming Gong
Keyword(s):  
Nonlinear Behavior ◽  
Reaction Model ◽  
Small Scale ◽  
Preliminary Design ◽  
Deep Foundation ◽  
Element Analysis ◽  
Design Guideline ◽  
Soil Stress ◽  
Load Tests ◽  
Scale Anchor

This paper presents a novel type of deep foundation — an anchor foundation with root caissons, which improve the soil–caisson interaction using penetrating roots. A simplified analytical procedure is proposed for calculating responses of the new anchor foundation subjected to combined vertical, horizontal, and moment loadings. Caisson–soil interaction is simulated by a Winkler subgrade reaction model, with an improved Winkler spring constant to consider the reinforcement effect of roots. The method incorporates limiting soil stress to investigate soil nonlinear behavior and a transfer matrix to represent nonhomogeneous soils, with a passive caisson model accounting for group effects. The effectiveness of the present approach is evaluated by comparison with full-scale field load tests and a finite element analysis on a small-scale anchor foundation to give a preliminary design guideline for the Ma’anshan Yangtze River Bridge in China.

scholarly journals Dynamic Loads and Response of a Spar Buoy Wind Turbine with Pitch-Controlled Rotating Blades: An Experimental Study

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3598
Author(s):  
Sara Russo ◽  
Pasquale Contestabile ◽  
Andrea Bardazzi ◽  
Elisa Leone ◽  
Gregorio Iglesias ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Degrees Of Freedom ◽  
Large Scale ◽  
Laboratory Data ◽  
Nonlinear Behavior ◽  
Offshore Wind ◽  
Small Scale ◽  
Wave Steepness ◽  
Design Factor

New large-scale laboratory data are presented on a physical model of a spar buoy wind turbine with angular motion of control surfaces implemented (pitch control). The peculiarity of this type of rotating blade represents an essential aspect when studying floating offshore wind structures. Experiments were designed specifically to compare different operational environmental conditions in terms of wave steepness and wind speed. Results discussed here were derived from an analysis of only a part of the whole dataset. Consistent with recent small-scale experiments, data clearly show that the waves contributed to most of the model motions and mooring loads. A significant nonlinear behavior for sway, roll and yaw has been detected, whereas an increase in the wave period makes the wind speed less influential for surge, heave and pitch. In general, as the steepness increases, the oscillations decrease. However, higher wind speed does not mean greater platform motions. Data also indicate a significant role of the blade rotation in the turbine thrust, nacelle dynamic forces and power in six degrees of freedom. Certain pairs of wind speed-wave steepness are particularly unfavorable, since the first harmonic of the rotor (coupled to the first wave harmonic) causes the thrust force to be larger than that in more energetic sea states. The experiments suggest that the inclusion of pitch-controlled, variable-speed blades in physical (and numerical) tests on such types of structures is crucial, highlighting the importance of pitch motion as an important design factor.

scholarly journals Isothermal Kinetic Analysis of the Thermal Decomposition of Wood Chips from an Apple Tree

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 195
Author(s):  
Ivan Vitázek ◽  
Martin Šotnar ◽  
Stella Hrehová ◽  
Kristína Darnadyová ◽  
Jan Mareček
Keyword(s):  
Thermal Decomposition ◽  
Apple Tree ◽  
Combustion Process ◽  
Reaction Model ◽  
Wood Chips ◽  
Small Scale ◽  
Exponential Factor ◽  
Air Atmosphere ◽  
First Order Chemical Reaction ◽  
Isothermal Kinetic

The thermal decomposition of wood chips from an apple tree is studied in a static air atmosphere under isothermal conditions. Based on the thermogravimetric analysis, the values of the apparent activation energy and pre-exponential factor are 34 ± 3 kJ mol−1 and 391 ± 2 min−1, respectively. These results have also shown that this process can be described by the rate of the first-order chemical reaction. This reaction model is valid only for a temperature range of 250–290 °C, mainly due to the lignin decomposition. The obtained results are used for kinetic prediction, which is compared with the measurement. The results show that the reaction is slower at higher values of degree of conversion, which is caused by the influence of the experimental condition. Nevertheless, the obtained kinetic parameters could be used for the optimization of the combustion process of wood chips in small-scale biomass boilers.

scholarly journals Simulation of Glass Fiber Reinforced Polypropylene Nanocomposites for Small Wind Turbine Blades

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 622
Author(s):  
Yasser Elhenawy ◽  
Yasser Fouad ◽  
Haykel Marouani ◽  
Mohamed Bassyouni
Keyword(s):  
Wind Turbine ◽  
Glass Fiber ◽  
Turbine Blades ◽  
Small Scale ◽  
Fiber Reinforced ◽  
Wind Turbine Blades ◽  
Element Analysis ◽  
Glass Fiber Reinforced ◽  
Horizontal Axis Wind Turbines ◽  
Multi Walled Carbon Nanotubes

This study aims to evaluate the effect of functionalized multi-walled carbon nanotubes (MWCNTs) on the performance of glass fiber (GF)-reinforced polypropylene (PP) for wind turbine blades. Support for theoretical blade movement of horizontal axis wind turbines (HAWTs), simulation, and analysis were performed with the Ansys computer package to gain insight into the durability of polypropylene-chopped E-glass for application in turbine blades under aerodynamic, gravitational, and centrifugal loads. Typically, polymer nanocomposites are used for small-scale wind turbine systems, such as for residential applications. Mechanical and physical properties of material composites including tensile and melt flow indices were determined. Surface morphology of polypropylene-chopped E-glass fiber and functionalized MWCNTs nanocomposites showed good distribution of dispersed phase. The effect of fiber loading on the mechanical properties of the PP nanocomposites was investigated in order to obtain the optimum composite composition and processing conditions for manufacturing wind turbine blades. The results show that adding MWCNTs to glass fiber-reinforced PP composites has a substantial influence on deflection reduction and adding them to chopped-polypropylene E-glass has a significant effect on reducing the bias estimated by finite element analysis.

Finite Element Analysis and Investigation of Double-Row Piles Supporting Structure

2013 ◽  
Vol 838-841 ◽  
pp. 779-785
Author(s):  
Liang Gu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Maximum Shear Stress ◽  
Horizontal Displacement ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Double Row ◽  
Element Analysis ◽  
Supporting Structure

The double-row piles supporting structure is a new type of supporting and protecting for deep foundation excavation. It is widely used to in design of deep foundation pit. Now how to simply and effectively design the structure of double-row piles is in a research and discuss stage. Using the Midas GTS finite element method, the displacement and stress distribution of double-row piles in the different stages of excavation are obtained, and the horizontal displacement and stress distribution of double-row piles in the different stages of excavation are calculated. The results of Midas GTS finite element analysis as follows: (1) after the excavation of foundation pit, the horizontal displacement of pile-top is maximum. The horizontal displacement decreases gradually with depth increases. And the displacement of front row piles is larger than that of back row piles; (2) the maximum shear stress is at the distance 5m to the foundation basement. The higher bending moment at the pile-top and the distance 10m to the foundation basement are consistent with the actual monitoring date. (3) the results of finite element analysis is close to the Richard software and actual monitoring data. It is show that using the finite element analysis to analyze the double-row piles supporting structure with is veritable and credible.

A Reduced-Order Model for the Preliminary Design of Small-Scale Radial Inflow Turbines

2021 ◽  
Author(s):  
Marco Manfredi ◽  
Marco Alberio ◽  
Marco Astolfi ◽  
Andrea Spinelli
Keyword(s):  
Heat Recovery ◽  
Internal Combustion Engines ◽  
Reduced Order Model ◽  
Pollutant Emissions ◽  
Small Scale ◽  
Preliminary Design ◽  
Order Model ◽  
Reduced Order ◽  
Wide Range ◽  
Loss Models

Abstract Power production from waste heat recovery represents an attractive and viable solution to contribute to the reduction of pollutant emissions generated by industrial plants and automotive sector. For transport applications, a promising technology can be identified in bottoming mini-organic Rankine cycles (ORCs), devoted to heat recovery from internal combustion engines (ICE). While commercial ORCs exploiting turbo-expanders in the power range of hundreds kW to several MW are a mature technology, well-established design guidelines are not yet available for turbines targeting small power outputs (below 50 kW). The present work develops a reduced-order model for the preliminary design of mini-ORC radial inflow turbines (RITs) for high-pressure ratio applications, suitable to be integrated in a comprehensive cycle optimization. An exhaustive review of existing loss models, whose development pattern is retraced up to the original approaches, is proposed. This investigation is finalized in a loss models effectiveness analysis performed by testing several correlations over six existing geometries. These test case turbines, operating with different fluids and covering a wide range of target expansion ratio, size, and gross power output, are then employed to carry out the validation procedure, whose results prove the robustness and prediction capability of the proposed reduced-order model.

Accuracy of Failure Criteria Commonly Used for Ship Collision Simulations

2018 ◽  
Author(s):  
R. Villavicencio ◽  
Bin Liu ◽  
Kun Liu
Keyword(s):  
Finite Element ◽  
Failure Criteria ◽  
Small Scale ◽  
Finite Element Models ◽  
Impact Loads ◽  
Large Scatter ◽  
Element Analysis ◽  
Advantages And Disadvantages ◽  
Ship Collision ◽  
Double Hull

The paper summarises observations of the fracture response of small-scale double hull specimens subjected to quasi-static impact loads by means of simulations of the respective experiments. The collision scenarios are used to evaluate the discretisation of the finite element models, and the energy-responses given by various failure criteria commonly selected for collision assessments. Nine double hull specimens are considered in the analysis so that to discuss the advantages and disadvantages of the different failure criterion selected for the comparison. Since a large scatter is observed from the numerical results, a discussion on the reliability of finite element analysis is also provided based on the present study and other research works found in the literature.

Verification of a Finite Element Analysis Procedure for Modeling the Nonlinear, Monotonic In-Plane Behavior of 4 Inch, Schedule 10, Stainless Steel, 90° Elbows

2003 ◽  
Author(s):  
James K. Wilkins
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stainless Steel ◽  
Nonlinear Behavior ◽  
Shell Element ◽  
Analysis Procedure ◽  
Hoop Strain ◽  
Element Analysis ◽  
Butt Welding ◽  
Strain Data

A project has been conducted to verify a finite element analysis procedure for studying the nonlinear behavior of 90°, stainless steel, 4 inch schedule 10, butt welding elbows. Two displacement controlled monotonic in-plane tests were conducted, one closing and one opening, and the loads, displacements, and strains at several locations were recorded. Stacked 90° tee rosette gages were used in both tests because of their ability to measure strain over a small area. ANSYS shell element 181 was used in the FEA reconciliations. The FEA models incorporated detailed geometric measurements of the specimens, including the welds, and material stress-strain data obtained from the attached straight piping. Initially, a mesh consisting of sixteen elements arrayed in 8 rings was used to analyze the elbow. The load-displacement correlation was quite good using this mesh, but the strain reconciliation was not. Analysis of the FEA results indicated that the axial and hoop strain gradients across the mid-section of the elbow were very high. In order to generate better strain correlations, the elbow mesh was refined in the mid-section of the elbow to include 48 elements per ring and an additional six rings, effectively increasing the element density by nine times. Using the refined mesh produced much better correlations with the strain data.

Nonlinear Finite Element Analysis of Diagonally Reinforced Coupling Beams with Head Bar Reinforcements

2013 ◽  
Vol 831 ◽  
pp. 137-140
Author(s):  
Kang Min Lee ◽  
Liu Yi Chen ◽  
Rui Li ◽  
Keun Yeong Oh ◽  
Young Soo Chun
Keyword(s):  
Finite Element ◽  
Construction Projects ◽  
Nonlinear Behavior ◽  
Lateral Loads ◽  
Coupling Beams ◽  
Element Analysis ◽  
Coupled Wall ◽  
Finite Element Software ◽  
Small Depth ◽  
Coupled Wall Systems

Coupling beams resist lateral loads efficiently is well known in coupled wall systems. In many cases, geometric limits result in coupling beams that are deep in relation to their clear span. Coupling beams with small depth-to-span ratio shall be reinforced with two intersecting groups of diagonally placed bars symmetrical along the mid-span. It's always hard to optimize construction projects. This paper used the finite element software (Abaqus) to analysis and simulate the nonlinear behavior of a new reinforcement called head bar and compared the results to the current standards.

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