Comparative Study of Dynamics of Gravity Cages With Different Meshes in Waves and Current

2016 ◽  
Author(s):  
Xinxin Wang ◽  
Rong Wan ◽  
Fenfang Zhao ◽  
Liuyi Huang ◽  
Peng Sun ◽  
...  
Keyword(s):  
Case Studies ◽  
Numerical Models ◽  
Water Tank ◽  
Mooring Lines ◽  
Finite Element Program ◽  
Comparison Results ◽  
Gravity Cage ◽  
Element Program ◽  
Response Amplitude Operators ◽  
Uniform Currents

To investigate the dynamics of gravity cage, the finite element program Aqua-FE™, was applied to gravity cages with two different meshes, square-mesh net and diamond-mesh net. Two case studies are chosen to compare the dynamics of cages based on the numerical modeling techniques. The numerical models were developed in Aqua-FE™ to simulate the effects of waves and current. They were validated by comparison with water tank results. The comparison showed good agreement. In both case studies, we consider several loading conditions consisting of different uniform currents and monochromatic waves. Assuming that the system can be modeled as a linear system, we investigated the motion response (heave, surge and pitch) characteristics of the fish cages with square-mesh net and diamond-mesh net, their deformation and the resultant tension in mooring lines. For different wave conditions, we study the storm response of the two cages based on the response amplitude operators (RAOs). In particular, the length of the grid line has significantly effect on the motion of the cage and the tension in mooring lines in wave. In additional, the effect of the mesh shape on the motion of the cage and tension in mooring lines is also analyzed. The comparison results show that the surge motion of the fish cage with square-mesh net is significantly larger than that with diamond-mesh net.

Nonlinear Analysis of Steel Reinforced High Strength and High Performance Concrete Eccentric Columns

2010 ◽  
Vol 450 ◽  
pp. 223-226 ◽  
Author(s):  
Shan Suo Zheng ◽  
Wei Wang ◽  
Bin Wang ◽  
Lei Li ◽  
Yi Hu
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Numerical Models ◽  
Constitutive Models ◽  
High Strength ◽  
Failure Criteria ◽  
Experimental Results ◽  
Finite Element Program ◽  
Calculation Results ◽  
Element Program

According to experiment of four steel reinforced high strength and high performance concrete(SRHSHPC) columns with different eccentricity, this paper establishes four equally parameter numerical models by finite element program ANSYS. The failure mechanism, failure mode and mechanical behaviors of the SRHSHPC columns with large and small eccentricity can be revealed by comparing the numerical simulation results with the corresponding experimental results. And the approximate plane-section assumption in SRHSHPC eccentric columns is verified by the study of the relationship between load and strain. It is shown that when constitutive models and failure criteria of SRHSHPC and steel are in precise case, the calculation results agree well with the corresponding experimental results.

An experimental and finite element study of the torsional behaviour of T-joints in automotive structures

2001 ◽  
Vol 215 (2) ◽  
pp. 231-240 ◽  
Author(s):  
M M K Lee ◽  
T Pine ◽  
T B Jones
Keyword(s):  
Finite Element ◽  
Laboratory Testing ◽  
Numerical Models ◽  
General Purpose ◽  
Test Results ◽  
T Joints ◽  
Finite Element Program ◽  
Automotive Components ◽  
Element Program ◽  
Torsional Properties

Single box sections and T-joints (two box sections joined together at right angles) are commonly used to represent automotive components, such as pillars and sills, in laboratory testing. In the work presented herein, the torsional properties of T-joints were determined both experimentally and numerically. A factorial-design test programme comparing adhesive-bonded and spot-welded T-joints was carried out. Numerical models, generated using a general-purpose finite element program and validated against the test results, were used to investigate further the behaviour of the connection between the two box sections in a T-joint. The joining technique and the joint eccentricity at the connection (the distance of the join from the vertical box section) were found to influence the torsional properties of T-joints. Finally, an automotive T-component was analysed to examine the applicability of the T-joint results to more complex components.

scholarly journals Improving Blast Performance of Reinforced Concrete Panels Using Sacrificial Cladding with Hybrid-Multi Cell Tubes

Modelling ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 149-165
Author(s):  
Mahmoud Abada ◽  
Ahmed Ibrahim ◽  
S.J. Jung
Keyword(s):  
Reinforced Concrete ◽  
Numerical Models ◽  
Plate Thickness ◽  
Core Layer ◽  
Engineering Structures ◽  
Finite Element Program ◽  
Explicit Finite Element ◽  
Element Program ◽  
Thin Walled ◽  
The Impact

The utilization of sacrificial layers to strengthen civilian structures against terrorist attacks is of great interest to engineering experts in structural retrofitting. The sacrificial cladding structures are designed to be attached to the façade of structures to absorb the impact of the explosion through the facing plate and the core layer progressive plastic deformation. Therefore, blast load striking the non-sacrificial structure could be attenuated. The idea of this study is to construct a sacrificial cladding structure from multicellular hybrid tubes to protect the prominent bearing members of civil engineering structures from blast hazard. The hybrid multi-cell tubes utilized in this study were out of staking composite layers (CFRP) around thin-walled tubes; single, double, and quadruple (AL) thin-walled tubes formed a hybrid single cell tube (H-SCT), a hybrid double cell tube (H-DCT), and a hybrid quadruple cell tube (H-QCT). An unprotected reinforced concrete (RC) panel under the impact of close-range free air blast detonation was selected to highlight the effectiveness of fortifying structural elements with sacrificial cladding layers. To investigate the proposed problem, Eulerian–Lagrangian coupled analyses were conducted using the explicit finite element program (Autodyn/ANSYS). The numerical models’ accuracy was validated with available blast testing data reported in the literature. Numerical simulations showed a decent agreement with the field blast test. The proposed cladding structures with different core topologies were applied to the unprotected RC slabs as an effective technique for blast loading mitigation. Mid-span deflection and damage patterns of the RC panels were used to evaluate the blast behavior of the structures. Cladding structure achieved a desired protection for the RC panel as the mid-span deflection decreased by 62%, 78%, and 87% for H-SCT, H-DCT, and H-QCT cores, respectively, compared to the unprotected panels. Additionally, the influence of the skin plate thickness on the behavior of the cladding structure was investigated.

scholarly journals Numerical Analysis of Segmental Post Tensioned Concrete Beams Exposed to High Fire Temperature

2019 ◽  
Vol 9 (5) ◽  
pp. 4759-4768
Author(s):  
H. M. Hekmet ◽  
A. F. Izzet
Keyword(s):  
Experimental Work ◽  
Prestressed Concrete ◽  
Elevated Temperatures ◽  
Concrete Beams ◽  
Numerical Models ◽  
Reference Beam ◽  
Finite Element Program ◽  
Simply Supported ◽  
Element Program ◽  
Main Factors

The main objective of this study is to characterize the main factors which may affect the behavior of segmental prestressed concrete beams comprised of multi segments. The 3-D finite element program ABAQUS was utilized. The experimental work was conducted on twelve simply supported segmental prestressed concrete beams divided into three groups depending on the precast segments number. They all had an identical total length of 3150mm, but each had different segment numbers (9, 7, and 5 segments), in other words, different segment lengths. To simulate the genuine fire disasters, nine beams were exposed to high-temperature flame for one hour, the selected temperatures were 300°C (572°F), 500°C (932°F) and 700°C (1292°F) as recommended by ASTM–E119. Four numerical models have been utilized to represent the unburned and the burned specimens at the three elevated temperatures. Calibration and simulation of the experimental work were conducted, while comparisons were made with the experimental results. These included the prestress effect, load-deflection relation under applied load, and load at failure of the reference beam and the beams after the exposure to fire.

scholarly journals Common irregularities and its effects on reinforced concrete building response

2021 ◽  
Vol 17 (1) ◽  
pp. 63-73
Author(s):  
Krishna Ghimire ◽  
Hemchandra Chaulagain
Keyword(s):  
Reinforced Concrete ◽  
Seismic Vulnerability ◽  
Numerical Models ◽  
Time History ◽  
Functional Requirements ◽  
Finite Element Program ◽  
Reinforced Concrete Building ◽  
Concrete Building ◽  
Element Program ◽  
Dynamic Time

In most of the countries, the irregular building construction is popular for fulfilling both aesthetic and functional requirements. However, the evidence of past earthquakes in Nepal and the globe demonstrated the higher level of seismic vulnerability of the buildings due to irregularities. Considering this fact, the present study highlighted the common irregularities and its effect on reinforced concrete building response. The effect of structural irregularities was studied through numerical analysis. The geometrical, mass and stiffness irregularities were created by removing bays in different floor levels and removing the columns at different sections respectively. In this study, the numerical models were created in finite element program SAP2000. The structural performance was studied using both non-linear static pushover and dynamic time history analysis. The results indicate that the level of irregularities significantly influenced the behavior of structures.

Hull-Mooring Coupled Dynamic Analysis of Two Side-by-Side Operating Vessels

2010 ◽  
Author(s):  
Mahdi Mirzaei ◽  
Mehdi Shafieefar ◽  
Mohammad Reza Moharrami
Keyword(s):  
The Other ◽  
Coupled Analysis ◽  
Mooring Line ◽  
Mooring Lines ◽  
Gas Field ◽  
Finite Element Program ◽  
Coupled Dynamic Analysis ◽  
Element Program ◽  
The Mean ◽  
The Persian Gulf

This paper contains the results of mooring analyses of two side-by-side operating crane barges in the installation procedure of a jacket type platform in an oil-gas field in the Persian Gulf. Since the vessels are proposed to operate next to a fixed structure, making sure about their displacements and a convenient clearance between them and the jacket is a highly important aspect of the design process. In essence, the analyses consist of setting an appropriate configuration and positioning of the vessels relative to each other, considering a reasonable gap between vessels and the jacket, connecting the vessels together, and studding the behavior of the moored system when it is subjected to a set of environments. In particular, an equilibrium configuration is found when the system is subjected to the mean force of the environment which consists of waves, wind gusts and currents. Then the dynamics of the system about the mean position is investigated. In order to study the influence of a dynamic mooring analysis, two cases are compared; one considering weight and buoyancy as the only forces acting on the lines and carrying out a quasi-static mooring analysis, and the other taking into account the hydrodynamic forces from the mooring lines. An accurate and efficient finite element program for the coupled analysis of the hull-mooring system is used and two types of modeling the connected vessels are compared; one using joints with restraints for all relative motions but in relative roll, and the other using slings and fenders. In all cases, the results of time domain analyses consisting of mooring line loads and motion responses of the vessels are presented in time histories and the statistics are studied.

scholarly journals Application of Fracture Mechanics to Cracking Problems in Soils

2014 ◽  
Vol 8 (1) ◽  
pp. 1-8 ◽  
Author(s):  
G. Juárez-Luna ◽  
G. Ayala
Keyword(s):  
Fracture Mechanics ◽  
Numerical Models ◽  
Practical Interest ◽  
Critical Stress Intensity Factor ◽  
Critical Conditions ◽  
Finite Element Program ◽  
Linear Elastic ◽  
Element Program ◽  
Elastic Fracture ◽  
Geotechnical Studies

This paper analyzes the problem of fracture in soils using the linear elastic fracture mechanics theory. Six cases of practical interest are investigated where the soil is subjected to different critical conditions that may produce cracks. To model the phenomenon of crack propagation, a two-dimensional fracture mechanics finite element program is used. In all cases, the properties of clays in the Valley of Mexico was used. The self-weight of the soil is considered as the main cause of geostatic stresses in the medium. Based on results from previous studies, the value of the critical stress intensity factor is calculated and validated. It is assumed that, only mode I fracture occurs. The crack depths obtained with the numerical models are congruent with the field data of existing geotechnical studies in the Valley of Mexico.

Friction Force and Stresses Analysis for Contact of Assembled Details

2006 ◽  
Vol 113 ◽  
pp. 334-338
Author(s):  
Z. Dreija ◽  
O. Liniņš ◽  
Fr. Sudnieks ◽  
N. Mozga
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Plastic Deformation ◽  
Friction Force ◽  
Sliding Friction ◽  
Friction Model ◽  
Contact Interface ◽  
Finite Element Program ◽  
Elastic Plastic ◽  
Element Program

The present work deals with the computation of surface stresses and deformation in the presence of friction. The evaluation of the elastic-plastic contact is analyzed revealing three distinct stages that range from fully elastic through elastic-plastic to fully plastic contact interface. Several factors of sliding friction model are discussed: surface roughness, mechanical properties and contact load and areas that have strong effect on the friction force. The critical interference that marks the transition from elastic to elastic- plastic and plastic deformation is found out and its connection with plasticity index. A finite element program for determination contact analysis of the assembled details and due to details of deformation that arose a normal and tangencial stress is used.

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