scholarly journals A non-associative macro-element model for vertical plate anchors in clay

2021 ◽  
Author(s):  
Anderson Peccin da Silva ◽  
Andrea Diambra ◽  
Dimitrios K. Karamitros ◽  
Shiao Huey Chow
Keyword(s):  
Peak Load ◽  
Element Model ◽  
Offshore Structures ◽  
Model Parameters ◽  
Hardening Rule ◽  
Pull Out ◽  
Proposed Model ◽  
Plastic Potential ◽  
Plastic Hardening ◽  
Macro Element

This work proposes a new plastic hardening, non-associative macro-element model to predict the behaviour of anchors in clay for floating offshore structures during keying and up to the peak load. Building on available models for anchors, a non-associated plastic potential is introduced to improve prediction of anchor trajectory and loss of embedment at peak conditions for a large range of padeye offsets and different pull-out directions. The proposed model also includes a displacement-hardening rule to simulate the force and displacement mobilisation at the early stages of the keying process. The model is challenged and validated against different sets of numerical and centrifuge data. This extensive validation process revealed that two of the four newly introduced model parameters assume a constant value for the range of simulated cases. This suggests that only two of the newly introduced parameters may need to be calibrated for the use of the proposed macro-element model in practice.

scholarly journals Macro-element modelling of suction-embedded plate anchors for floating offshore structures

2019 ◽  
Vol 92 ◽  
pp. 16009
Author(s):  
Anderson Peccin Da Silva ◽  
Andrea Diambra ◽  
Dimitris Karamitros
Keyword(s):  
Good Accuracy ◽  
Large Range ◽  
Element Model ◽  
Offshore Structures ◽  
Hardening Rule ◽  
Centrifuge Tests ◽  
Wide Range ◽  
Plastic Potential ◽  
Macro Element ◽  
Plate Anchors

This work presents a new macro-element model to predict the behaviour of Suction Embedded Plate Anchors (SEPLAs) for floating offshore structures during keying and loading stages. Differently from previously published models for anchors, this new model is characterised by (i) a non-associated plastic potential with the aim of improving the prediction of anchor trajectory for the whole displacement domain and for a large range of padeye offsets; and (ii) by a strain-hardening rule enabling to predict the force and displacement mobilisation from the early stages of the keying process. The model was calibrated against LDFE analyses and compared with a broad set of LDFE and centrifuge tests results. The model proves capable of reproducing anchor rotation and displacement with good accuracy for a wide range of padeye offsets and distinct studies from the literature.

Effect of different lapping orders on mechanical performance and nugget forming process for three-sheet dissimilar resistance spot welding joints between DC06 and unequal-thickness hot-stamped B1500HS steel sheets

2021 ◽  
Vol 118 (1) ◽  
pp. 112
Author(s):  
Xin Mao ◽  
Zhi Cheng ◽  
Qiang Zhu ◽  
Wurong Wang ◽  
Xicheng Wei ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Formation Mechanism ◽  
Mechanical Performance ◽  
Peak Load ◽  
Element Model ◽  
Type I ◽  
Type Ii ◽  
Forming Process ◽  
Pull Out ◽  
Nugget Formation

In this study, the mechanical properties of two welded joints under different lapping orders (B1500HS-1.4 mm/B1500HS-1.6 mm/DC06, denoted as type I; B1500HS-1.4 mm/DC06/B1500HS-1.6 mm, denoted type II) were compared. The nugget formation mechanism was analysed by a coupled electrical-thermal finite element model (FEM). It is found that different lapping orders significantly affect the mechanical properties of three-sheet RSW joints. All RSW joints tend to fail in the pull-out or tearing failure mode. The peak load of the two interfaces of type II RSW joint is more balanced, and the failure load of which is much higher than that of the type I RSW joint; The warpage was observed at type I welded joint. Considered the load-carrying capacity, type II was excellent. The simulation results indicate that the diameter of the weld nugget at the upper interface of the type I RSW joint was larger than that on the other interfaces, which agree well with the experimental results. The nugget formation mechanism of dissimilar high strength steel three-sheet RSW joint was obtained that forming the nugget firstly from two interfaces and final formed nuggets were asymmetric.

scholarly journals Development of a macro-element model for rockfall steel wires using

2021 ◽  
Author(s):  
Marco Previtali ◽  
◽  
Matteo Ciantia ◽  
Saverio Spadea ◽  
Riccardo Castellanza ◽  
...  
Keyword(s):  
Element Model ◽  
Tensile Tests ◽  
Analytical Models ◽  
Uniaxial Tensile ◽  
Steel Wires ◽  
Protection Systems ◽  
Physical Tests ◽  
Plastic Domain ◽  
Plastic Hardening ◽  
Macro Element

This paper aims to present a few aspects of the development of a plastic-hardening macro-element model for steel wires in flexible protection systems. First, the material behaviour is obtained using uniaxial tensile tests. Successively, the evolution of the elastic and plastic domain is obtained using a combination of physical tests, analytical models, and numerical simulations. Finally, the results obtained with the macro-element model are compared to those obtained using other approaches found in literature.

In-Plane Flexible Ring Tire Model—Part 1: Modeling and Parameter Identification

2018 ◽  
Vol 46 (3) ◽  
pp. 174-219 ◽  
Author(s):  
Bin Li ◽  
Xiaobo Yang ◽  
James Yang ◽  
Yunqing Zhang ◽  
Zeyu Ma
Keyword(s):  
Static Load ◽  
Model Parameters ◽  
Tire Model ◽  
Test Results ◽  
Lumped Mass ◽  
Virtual Test ◽  
Proposed Model ◽  
Particle Swarm Method ◽  
Vehicle Dynamic Simulation ◽  
Flexible Ring

ABSTRACT The tire model is essential for accurate and efficient vehicle dynamic simulation. In this article, an in-plane flexible ring tire model is proposed, in which the tire is composed of a rigid rim, a number of discretized lumped mass belt points, and numerous massless tread blocks attached on the belt. One set of tire model parameters is identified by approaching the predicted results with ADAMS® FTire virtual test results for one particular cleat test through the particle swarm method using MATLAB®. Based on the identified parameters, the tire model is further validated by comparing the predicted results with FTire for the static load-deflection tests and other cleat tests. Finally, several important aspects regarding the proposed model are discussed.

EXPONENTIATED HALF-LOGISTIC LOMAX DISTRIBUTION WITH PROPERTIES AND APPLICATION

2019 ◽  
Vol XVI (2) ◽  
pp. 1-11
Author(s):  
Farrukh Jamal ◽  
Hesham Mohammed Reyad ◽  
Soha Othman Ahmed ◽  
Muhammad Akbar Ali Shah ◽  
Emrah Altun
Keyword(s):  
Real Data ◽  
Continuous Model ◽  
Model Parameters ◽  
Data Set ◽  
Lomax Distribution ◽  
Mathematical Properties ◽  
Proposed Model ◽  
Probability Weighted Moment ◽  
Record Statistics ◽  
Maximum Likelihood Criterion

A new three-parameter continuous model called the exponentiated half-logistic Lomax distribution is introduced in this paper. Basic mathematical properties for the proposed model were investigated which include raw and incomplete moments, skewness, kurtosis, generating functions, Rényi entropy, Lorenz, Bonferroni and Zenga curves, probability weighted moment, stress strength model, order statistics, and record statistics. The model parameters were estimated by using the maximum likelihood criterion and the behaviours of these estimates were examined by conducting a simulation study. The applicability of the new model is illustrated by applying it on a real data set.

scholarly journals A General Temperature-Dependent Stress–Strain Constitutive Model for Polymer-Bonded Composite Materials

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1393
Author(s):  
Xiaochang Duan ◽  
Hongwei Yuan ◽  
Wei Tang ◽  
Jingjing He ◽  
Xuefei Guan
Keyword(s):  
Composite Materials ◽  
Constitutive Model ◽  
Model Parameters ◽  
Temperature Dependent ◽  
Stress Strain ◽  
Proposed Model ◽  
Single Temperature ◽  
Testing Data ◽  
Bonded Composite ◽  
Tension And Compression

This study develops a general temperature-dependent stress–strain constitutive model for polymer-bonded composite materials, allowing for the prediction of deformation behaviors under tension and compression in the testing temperature range. Laboratory testing of the material specimens in uniaxial tension and compression at multiple temperatures ranging from −40 ∘C to 75 ∘C is performed. The testing data reveal that the stress–strain response can be divided into two general regimes, namely, a short elastic part followed by the plastic part; therefore, the Ramberg–Osgood relationship is proposed to build the stress–strain constitutive model at a single temperature. By correlating the model parameters with the corresponding temperature using a response surface, a general temperature-dependent stress–strain constitutive model is established. The effectiveness and accuracy of the proposed model are validated using several independent sets of testing data and third-party data. The performance of the proposed model is compared with an existing reference model. The validation and comparison results show that the proposed model has a lower number of parameters and yields smaller relative errors. The proposed constitutive model is further implemented as a user material routine in a finite element package. A simple structural example using the developed user material is presented and its accuracy is verified.

scholarly journals Comprehensive Wind and Wave Statistics and Extreme Values for Design and Analysis of Marine Structures in the Adriatic Sea

2021 ◽  
Vol 9 (5) ◽  
pp. 522
Author(s):  
Marko Katalinić ◽  
Joško Parunov
Keyword(s):  
Adriatic Sea ◽  
Extreme Values ◽  
Wave Climate ◽  
Offshore Structures ◽  
Model Parameters ◽  
Peak Period ◽  
Significant Wave ◽  
Wave Statistics ◽  
Wave Heights ◽  
Almost All

Wind and waves present the main causes of environmental loading on seagoing ships and offshore structures. Thus, its detailed understanding can improve the design and maintenance of these structures. Wind and wave statistical models are developed based on the WorldWaves database for the Adriatic Sea: for the entire Adriatic Sea as a whole, divided into three regions and for 39 uniformly spaced locations across the offshore Adriatic. Model parameters are fitted and presented for each case, following the conditional modelling approach, i.e., the marginal distribution of significant wave height and conditional distribution of peak period and wind speed. Extreme significant wave heights were evaluated for 20-, 50- and 100-year return periods. The presented data provide a consistent and comprehensive description of metocean (wind and wave) climate in the Adriatic Sea that can serve as input for almost all kind of analyses of ships and offshore structures.

scholarly journals Corrosion of Steel Rebars in Anoxic Environments. Part II: Pit Growth Rate and Mechanical Strength

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2547
Author(s):  
Elena Garcia ◽  
Julio Torres ◽  
Nuria Rebolledo ◽  
Raul Arrabal ◽  
Javier Sanchez
Keyword(s):  
Mechanical Strength ◽  
Chloride Content ◽  
Element Model ◽  
Offshore Structures ◽  
Anoxic Environments ◽  
Electrochemical Parameters ◽  
Cathode Area ◽  
Optical Profilometer ◽  
Set Up ◽  
Corrosion Of Steel

Reinforced concrete may corrode in anoxic environments such as offshore structures. Under such conditions the reinforcement fails to passivate completely, irrespective of chloride content, and the corrosion taking place locally induces the growth of discrete pits. This study characterised such pits and simulated their growth from experimentally determined electrochemical parameters. Pit morphology was assessed with an optical profilometer. A finite element model was developed to simulate pit growth based on electrochemical parameters for different cathode areas. The model was able to predict long-term pit growth by deformed geometry set up. Simulations showed that pit growth-related corrosion tends to maximise as cathode area declines, which lower the pitting factor. The mechanical strength developed by the passive and prestressed rebar throughout its service life was also estimated. Passive rebar strength may drop by nearly 20% over 100 years, whilst in the presence of cracking from the base of the pit steel strength may decline by over 40%.

scholarly journals Experimental and Numerical Investigation on the Steel Reinforced Grout (SRG) Composite-to-Concrete Bond

2020 ◽  
Vol 4 (4) ◽  
pp. 182
Author(s):  
Luciano Ombres ◽  
Salvatore Verre
Keyword(s):  
Bond Length ◽  
Failure Modes ◽  
Peak Load ◽  
Element Model ◽  
Test Results ◽  
Shear Tests ◽  
Bond Slip ◽  
Bond Behavior ◽  
Direct Shear Tests ◽  
Inorganic Matrix

In the paper, the bond between a composite strengthening system consisting of steel textiles embedded into an inorganic matrix (steel reinforced grout, SRG) and the concrete substrate, is investigated. An experimental investigation was carried out on medium density SRG specimens; direct shear tests were conducted on 20 specimens to analyze the effect of the bond length, and the age of the composite strip on the SRG-to-concrete bond behavior. In particular, the tests were conducted considering five bond length (100, 200, 250, 330, and 450 mm), and the composite strip’s age 14th, 21st, and 28th day after the bonding. Test results in the form of peak load, failure modes and, bond-slip diagrams were presented and discussed. A finite element model developed through commercial software to replicate the behavior of SRG strips, is also proposed. The effectiveness of the proposed numerical model was validated by the comparison between its predictions and experimental results.

scholarly journals Flexural behavior of composite structural insulated panels with magnesium oxide board facings

2020 ◽  
Vol 20 (4) ◽  
Author(s):  
Łukasz Smakosz ◽  
Ireneusz Kreja ◽  
Zbigniew Pozorski
Keyword(s):  
Magnesium Oxide ◽  
Material Model ◽  
Expanded Polystyrene ◽  
Flexural Behavior ◽  
Joint Analysis ◽  
Model Parameters ◽  
Fe Model ◽  
Computational Results ◽  
Four Point Bending ◽  
Proposed Model

Abstract The current report is devoted to the flexural analysis of a composite structural insulated panel (CSIP) with magnesium oxide board facings and expanded polystyrene (EPS) core, that was recently introduced to the building industry. An advanced nonlinear FE model was created in the ABAQUS environment, able to simulate the CSIP’s flexural behavior in great detail. An original custom code procedure was developed, which allowed to include material bimodularity to significantly improve the accuracy of computational results and failure mode predictions. Material model parameters describing the nonlinear range were identified in a joint analysis of laboratory tests and their numerical simulations performed on CSIP beams of three different lengths subjected to three- and four-point bending. The model was validated by confronting computational results with experimental results for natural scale panels; a good correlation between the two results proved that the proposed model could effectively support the CSIP design process.

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