Experimental and Numerical Study on Holding Power of Rectangular-Shaped Anchors

2018 ◽  
Author(s):  
Kimihiro Toh ◽  
Yusuke Fukumoto ◽  
Takao Yoshikawa
Keyword(s):  
Numerical Study ◽  
Distinct Element ◽  
Estimation Method ◽  
Experimental Results ◽  
Element Analysis ◽  
Holding Power ◽  
Penetration Mechanism ◽  
History Of ◽  
Sea Area ◽  
Marine Floating Structures

This paper discusses the experimental and numerical investigations for the holding power of rectangular-shaped anchors. As the offshore developments are promoted, the mooring systems are often used as the station keeping systems of the marine floating structures. From a viewpoint of the energy consumption, the mechanical mooring systems with anchors are better than the dynamic mooring systems with thrusters. Up to now, however, the research and development regarding the mooring systems with the high holding anchors in the deep sea area, especially more than 500 m in depth, have hardly been carried out in Japan. In most cases, the conventional anchor shapes have experimentally and/or empirically been decided. In addition, only a few studies which relate the numerical analysis to the experimental test have been performed for the holding power. In order to obtain the optimal shape of anchors theoretically, therefore, the purpose of this study is to develop the estimation method for the holding power and to clarify the penetration mechanism of anchors in soil. In this paper, a series of experiments utilizing the small-sized anchor model is conducted. Here, the fluke shape of specimen is modeled by the rectangular flat plate for simplicity. From several experiments varying the geometric characteristics of the anchor model, the experimental results, e.g., the history of the holding power, the penetration depth, and the fluke surface angle at the maximum holding power, are obtained. Furthermore, the numerical simulation to evaluate the holding power is also carried out using the dynamic explicit non-linear finite element analysis (NLFEA) code, LS-DYNA, as well as the in-house distinct element method (DEM) code. From the comparison between the numerical results and the experimental results, the calculation accuracy is verified.

scholarly journals Preliminary Experimental and Numerical Study of Metal Element with Notches Reinforced by Composite Materials

2021 ◽  
Vol 5 (5) ◽  
pp. 134
Author(s):  
Paweł J. Romanowicz ◽  
Bogdan Szybiński ◽  
Mateusz Wygoda
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Numerical Study ◽  
Correlation Method ◽  
Industrial Applications ◽  
Experimental Results ◽  
Image Correlation ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Wide Range

The presented study is related to the application of the composite overlays used in order to decrease the effect of the stress concentrations around the cut-outs in structural metal elements. The proposed approach with the application of the digital image correlation extends the recently presented studies. Such structural elements with openings of various shapes have been accommodated for a wide range of industrial applications. These structures exhibit certain stress concentrations which decrease their durability and strength. To restore their strength, various reinforcing overlays can be used. In the present paper, the flat panel structure without and with the composite overlays made of HEXCEL TVR 380 M12/26%/R-glass/epoxy is under the experimental and the numerical study. Particular attention is paid to the investigation of the samples with the rectangular holes, which for smooth rounded corners offer a higher durability than the samples with the circular hole of the same size. The experimental results are obtained for the bare element and are reinforced with composite overlay samples. The experimental results are obtained with the use of the Digital Image Correlation method, while the numerical results are the product of the Finite Element Analysis. In the numerical analysis, the study of the shape, size and fiber orientation in applied overlays is done. The reduction of the stress concentration observed in opening notches has confirmed the effectiveness of the overlay application. In the investigated example, the application of the square composite overlay increased the structure strength even by 25%.

scholarly journals EXPERIMENTAL AND NUMERICAL STUDY ON COLUMN-FOUNDATION CONNECTION THROUGH EXTERNAL SOCKET

2021 ◽  
Vol 27 (3) ◽  
pp. 162-174
Author(s):  
Haiying Ma ◽  
Minghui Lai ◽  
Xuefei Shi ◽  
Zhen Cao ◽  
Junyong Zhou
Keyword(s):  
Numerical Study ◽  
Highway Bridges ◽  
Experimental Results ◽  
Bridge Foundations ◽  
Construction Time ◽  
Element Analysis ◽  
Bridge Column ◽  
Column Foundation ◽  
Socket Connection ◽  
Connection Design

In practice, bridge foundations and pier columns are usually constructed with cast-in-place concrete. Precast columns are currently widely used in highway bridges in China, which can save construction time and improve concrete quality. The connection between precast bridge columns and the foundation can affect how forces transfer from one to the other. This paper investigates using external sockets to form a connection between the bridge column and foundation. This method can accelerate the bridge construction time with the additional advantages of improving the orientation and creating a large erection tolerance. Two types of connections are presented and tested to investigate the behavior of the column-foundation connections and find a more suitable way to use external socket connections. The experimental results show that the column-foundation connection design satisfies the design requirements. The results also show that roughening the column surface within the external socket is more effective at connecting the column to the foundation when using an external socket compared to attaching a steel plate on the column. The experimental results are validated with a finite element analysis, resulting in a proposal regarding the column-foundation connection behavior as well as design recommendations for the external socket connection.

scholarly journals Exploratory Finite Element Analysis of Monolithic Toughened Glass Panes Subjected to Hard-Body Impact

2021 ◽  
Vol 1203 (2) ◽  
pp. 022145
Author(s):  
Marcin Kozłowski ◽  
Kinga Zemła ◽  
Magda Kosmal
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Numerical Study ◽  
Maximum Principal Stress ◽  
Drop Height ◽  
Toughened Glass ◽  
Element Analysis ◽  
Experimental Campaign ◽  
History Of ◽  
The Impact

Abstract The paper reports the results of an extensive experimental campaign, in which simply supported toughened glass samples with dimensions of 500 × 360 mm2 and three thicknesses (6, 8 and 10 mm) were subjected to hard-body impact. A steel ball (4.11 kg) was released from different drop heights, starting from 10 cm above the sample and increasing by 10 cm in each step until glass breakage occurred. In this way, for all samples a critical drop height (causing fracture of glass) was determined. Experiments were carried out for 35 samples for each thickness; thus 105 samples were tested in total. A 3D numerical model of the experimental setup was developed using the commercial finite element analysis (FEA) software ABAQUS and Implicit Dynamic solver. The numerical study was aimed at numerical reproduction of the experiments and determination of the maximum principal stress in the glass that occurs during the impact. To reduce the number of FEs and increase the computational efficiency of the simulations, only a quarter of the nominal geometry with appropriate boundary conditions were modelled. The simulations were performed for a given weight of the steel impactor, glass thickness and the corresponding critical/breaking drop height found in the experimental campaign. In this way, an impact strength of the toughened glass was retrospectively evaluated. The simulations were used to investigate the impact history in terms of stress in glass, acceleration and velocity. Moreover, the resulting history of impact force was determined.

Tire Cornering Simulation Using an Explicit Finite Element Analysis Code

1998 ◽  
Vol 26 (2) ◽  
pp. 109-119 ◽  
Author(s):  
M. Koishi ◽  
K. Kabe ◽  
M. Shiratori
Keyword(s):  
Finite Element Method ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Test System ◽  
Experimental Results ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Explicit Finite Element ◽  
Explicit Finite Element Analysis ◽  
Element Method

Abstract The finite element method has been used widely in tire engineering. Most tire simulations using the finite element method are static analyses, because tires are very complex nonlinear structures. Recently, transient phenomena have been studied with explicit finite element analysis codes. In this paper, the authors demonstrate the feasibility of tire cornering simulation using an explicit finite element code, PAM-SHOCK. First, we propose the cornering simulation using the explicit finite element analysis code. To demonstrate the efficiency of the proposed simulation, computed cornering forces for a 175SR14 tire are compared with experimental results from an MTS Flat-Trac Tire Test System. The computed cornering forces agree well with experimental results. After that, parametric studies are conducted by using the proposed simulation.

scholarly journals Design and analysis of concrete-filled tubular flange girders under combined loading

2021 ◽  
pp. 136943322110015
Author(s):  
Rana Al-Dujele ◽  
Katherine Ann Cashell
Keyword(s):  
Finite Element ◽  
Axial Force ◽  
Failure Modes ◽  
Numerical Study ◽  
Combined Loading ◽  
Torsional Stiffness ◽  
Fe Model ◽  
Combined Effects ◽  
Element Analysis ◽  
Hollow Section

This paper is concerned with the behaviour of concrete-filled tubular flange girders (CFTFGs) under the combination of bending and tensile axial force. CFTFG is a relatively new structural solution comprising a steel beam in which the compression flange plate is replaced with a concrete-filled hollow section to create an efficient and effective load-carrying solution. These members have very high torsional stiffness and lateral torsional buckling strength in comparison with conventional steel I-girders of similar depth, width and steel weight and are there-fore capable of carrying very heavy loads over long spans. Current design codes do not explicitly include guidance for the design of these members, which are asymmetric in nature under the combined effects of tension and bending. The current paper presents a numerical study into the behaviour of CFTFGs under the combined effects of positive bending and axial tension. The study includes different loading combinations and the associated failure modes are identified and discussed. To facilitate this study, a finite element (FE) model is developed using the ABAQUS software which is capable of capturing both the geometric and material nonlinearities of the behaviour. Based on the results of finite element analysis, the moment–axial force interaction relationship is presented and a simplified equation is proposed for the design of CFTFGs under combined bending and tensile axial force.

scholarly journals On Hydromechanical Interaction during Propagation of Localized Damage in Rocks

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 162
Author(s):  
A.A. Jameei ◽  
S. Pietruszczak
Keyword(s):  
Numerical Study ◽  
Fluid Pressure ◽  
Implicit Time ◽  
Integration Scheme ◽  
Internal Length ◽  
Element Analysis ◽  
Equivalent Permeability ◽  
Mechanical Coupling ◽  
Splitting Test ◽  
Localized Damage

This paper provides a mathematical description of hydromechanical coupling associated with propagation of localized damage. The framework incorporates an embedded discontinuity approach and addresses the assessment of both hydraulic and mechanical properties in the region intercepted by a fracture. Within this approach, an internal length scale parameter is explicitly employed in the definition of equivalent permeability as well as the tangential stiffness operators. The effect of the progressive evolution of damage on the hydro-mechanical coupling is examined and an evolution law is derived governing the variation of equivalent permeability with the continuing deformation. The framework is verified by a numerical study involving 3D simulation of an axial splitting test carried out on a saturated sample under displacement and fluid pressure-controlled conditions. The finite element analysis incorporates the Polynomial-Pressure-Projection (PPP) stabilization technique and a fully implicit time integration scheme.

scholarly journals Estimating Deterioration in the Concrete Tie-Ballast Interface Based on Vertical Tie Deflection Profile: A Numerical Study

2016 ◽  
Author(s):  
Hailing Yu
Keyword(s):  
Direct Detection ◽  
Numerical Study ◽  
Interface Condition ◽  
Vertical Deflection ◽  
Cohesive Elements ◽  
Material Loss ◽  
Element Analysis ◽  
Cross Sectional ◽  
Technical Requirements ◽  
Support Conditions

In ballasted concrete tie track, the tie-ballast interface can deteriorate resulting in concrete tie bottom abrasion, ballast pulverization and/or voids in tie-ballast interfaces. Tie-ballast voids toward tie ends can lead to unfavorable center binding support conditions that can result in premature concrete tie failure and possible train derailment. Direct detection of these conditions is difficult. There is a strong interest in assessing the concrete tie-ballast interface conditions indirectly using measured vertical deflections. This paper seeks to establish a link between the vertical deflection profile of a concrete tie top surface and the tie-ballast interface condition using the finite element analysis (FEA) method. The concrete tie is modeled as a concrete matrix embedded with prestressing steel strands or wires. The configurations of two commonly used concrete ties, one with 8 prestressing strands and the other with 20 prestressing wires, are employed in this study. All models are three-dimensional and symmetric about the tie center. A damaged plasticity model that can predict onset and propagation of tensile cracks is applied to the concrete material. The steel-concrete interface is homogenized and represented with a thin layer of cohesive elements sandwiched between steel and concrete elements. Strand- or wire-specific elasto-plastic bond models developed at the Volpe Center are applied to the cohesive elements to account for the interface bonding mechanisms. FE models are developed for both original and worn concrete ties, with the latter assuming hypothetical patterns of reduced cross sections resulting from abrasive interactions with the ballast. Static analyses of pretension release in these concrete ties are conducted, and vertical deflection gradients along tie lengths are calculated and shown to correspond well with the worn cross sectional patterns for a given reinforcement type. The ballast is further modeled with Extended Drucker-Prager plasticity, and hypothetical voids are applied toward the tie ends along the concrete tie-ballast interface to simulate center binding support conditions. The distance range over which the concrete tie is supported in the center is variable and yields different center binding severity. Static simulations are completed with vertical rail seat loads applied on the concrete tie-ballast assembly. The influences of various factors on the vertical deflection profile, including tie type, vertical load magnitude, center binding severity, cross sectional material loss and prestress loss, are examined based on the FEA results. The work presented in this paper demonstrates the potential of using the vertical deflection profile of concrete tie top surfaces to assess deteriorations in the tie-ballast interface. The simulation results further help to clarify minimum technical requirements on inspection technologies that measure concrete tie vertical deflection profiles.

Effects of Wind on the Heat Flow of FPSO Topsides Subject to Fire: An Experimental and Numerical Study

2010 ◽  
Author(s):  
Joon Young Yoon ◽  
Seong Hwan Kim ◽  
Gwon Cheol Yu ◽  
Jung Kwan Seo ◽  
Bong Ju Kim ◽  
...  
Keyword(s):  
Thermal Diffusion ◽  
Numerical Study ◽  
Wind Tunnel Test ◽  
Experimental Results ◽  
Test Facility ◽  
Test Model ◽  
Cfd Simulations ◽  
Fire Engineering ◽  
Diffusion Characteristics ◽  
Fire Loads

The aim of this paper is to examine the effect of wind on the thermal diffusion characteristics of floating production storage and offloading (FSPO) topside models subject to fire. It is motivated by the need to identify the fire loads on FPSO topsides, taking into account the effects of wind speed and direction. The results of an experimental and numerical study undertaken for these purposes are reported here. This paper is part of Phase II of the joint industry project on explosion and fire engineering of FPSOs (EFEF JIP) [1]. An experiment was performed on a 1/14-scale FPSO topside model using a wind tunnel test facility. The locations of the heat source of the fire were varied, as were the speed and direction of the wind, and the temperature distribution was measured. Computational fluid dynamics (CFD) simulations using the ANSYS CFX program were performed on the test model, with the results obtained compared with the experimental results. It is concluded that wind has a significant effect on the thermal diffusion characteristics of the test model and that the CFD simulations are in good agreement with the experimental results. The insights developed in this study will be very useful for the fire engineering of FPSO topsides.

Estimation of Fatigue Life for Hydraulic Excavator Boom under All Operating States

2011 ◽  
Vol 199-200 ◽  
pp. 463-469
Author(s):  
Qing Xin Ding ◽  
Ying Cheng Tian ◽  
Juan Chen ◽  
Jian Wen Chen ◽  
Kun Liang Hui ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Estimation Method ◽  
Maximum Principal Stress ◽  
Multiaxial Fatigue ◽  
Hydraulic Excavator ◽  
Dangerous Zone ◽  
Support Force ◽  
Contrast Analysis ◽  
History Of ◽  
Hinged Support

Fatigue is one of the most common failure mode in hydraulic excavator boom. To find the most fatigue dangerous operating state of boom and effectively improve the life of the structure, a new method is proposed for the estimation of fatigue life under all operation states. In the case of unknown the history of loading, firstly find out the hinged support force under all boom poses, then calculate the stress of every point of the boom under the actions of each group hinged support force via finite element method, and finally simulate all operating states through the poses combination, conducts analysis of multiaxial fatigue life in the maximum principal stress as the nominal stress, calculates the life and the most dangerous operating state in all points, and compares to obtain the most dangerous position and the life of the boom. The results of contrast analysis showed that: the most dangerous zone of the excavator boom calculated by the life estimation method of all operating states coincide with the actual destruction situation. The life of the structure can be greatly improved after a simple reasonable improvement of the parts.

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