Ultimate Strength of Box Girders With Incline Cracks

2015 ◽  
Author(s):  
Lei Ao ◽  
Deyu Wang
Keyword(s):  
Finite Element ◽  
Fourier Series ◽  
Crack Length ◽  
Ultimate Strength ◽  
Finite Element Models ◽  
Torsional Loading ◽  
Box Girders ◽  
Box Beam ◽  
Crack Angle ◽  
The Relationship

The aim of the present study is to investigate the residual ultimate strength characteristics of box girders with variable inclination cracks under torsional loading. A series of finite element models are established by changing the crack length and crack angle using a commercial FEA program, ABAQUS. The cracks are located at the center and torques are applied on both ends of the box beam. The accuracy of the nonlinear FEA results is verified by a comparison with previous predicted formulas. Based on the FEA results, the relationship between the residual ultimate strength and crack parameters can be indicated in a function with period of π in the form of Fourier series.

REINFORCEMENT OF AGEING SHIP STRUCTURES

2021 ◽  
Vol 160 (A3) ◽  
Author(s):  
D Chichì ◽  
Y Garbatov
Keyword(s):  
Monte Carlo Simulation ◽  
Finite Element ◽  
Ultimate Strength ◽  
Steel Plate ◽  
Plate Thickness ◽  
Compressive Load ◽  
Finite Element Models ◽  
Uniform Corrosion ◽  
Finite Element Analyses ◽  
Longitudinal Stiffeners

The objective of the present study is to investigate the possibility to recover the ultimate strength of a rectangular steel plate with a manhole shape opening subjected to a uniaxial compressive load and non-uniform corrosion degradation reinforced by additional stiffeners. Finite element analyses have been carried out to verify the possible design solutions. A total of four finite element models are generated, including 63 sub-structured models. The non-uniform corrosion has been generated by the Monte Carlo simulation. The reinforcement process covers three scenarios that include mounting of two longitudinal stiffeners, two longitudinal and two transverse stiffeners and the flange on the opening. The positioning of the stiffeners has also been studied. A total of 10 cases has been selected and tested for the numerical experiment. Three different assessments have been performed to evaluate the ultimate strength, weight and cost. Two additional studies on the effect of the plate thickness and slenderness have been also carried out.

Modal Velocity-Based Multiaxial Fatigue Damage Evaluation Using Simplified Finite Element Models

2020 ◽  
Vol 87 (11) ◽  
Author(s):  
Kurthan Kersch ◽  
Elmar Woschke
Keyword(s):  
Finite Element ◽  
Fatigue Damage ◽  
Cross Section ◽  
Multiaxial Fatigue ◽  
Finite Element Models ◽  
Damage Evaluation ◽  
Geometric Factors ◽  
The Relationship ◽  
General Method

Abstract This work proposes a new method for the fatigue damage evaluation of vibrational loads, based on preceding investigations on the relationship between stresses and modal velocities. As a first step, the influence of the geometry on the particular relationship is studied. Therefore, an analytic expression for Euler Bernoulli beams with a non-constant cross section is derived. Afterward, a general method for obtaining geometric factors from finite element (FE) models is proposed. In order to ensure a fast fatigue damage evaluation, strongly simplified FE-models are used for the determination of both factors and measurement locations. The entire method is demonstrated on three mechanical structures and indicates a better compromise between effort and accuracy than existing methods. For all examples, the usage of velocities and geometric factors obtained from simplified FE models enables a sufficient fatigue damage calculation.

Euler Buckling of Idealised Horizontal Pipeline Imperfections

2010 ◽  
Author(s):  
Gary Cumming ◽  
Andrew Rathbone
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Friction Factor ◽  
Finite Element Models ◽  
Bend Radius ◽  
Element Analysis ◽  
Euler Buckling ◽  
Critical Buckling Force ◽  
The Relationship

Imperfections introduced by pipelay can not be known until installation is complete; therefore a common approach is to perform finite element analysis of idealised horizontal imperfections to determine critical buckling forces. Rundsag et al 2008 [1], showed that the critical buckling force for a snake lay geometry is directly proportional to the pipeline bend radius. Rathbone et al 2008 [2] showed that, with decreasing arch lengths, the pipeline critical buckling force is proportional to the change in the offset angle. This paper looks at the relationship between the minimum critical buckling force and the horizontal offset angle of the pipeline, considering an Euler buckling approach. The resulting relationship that estimates the critical buckle load based on pipeline stiffness and weight, offset angle and friction factor is then compared against idealised finite element models.

Residual Ultimate Strength of Steel Plates with Longitudinal Crack and Pitting Corrosion under Axial compression: Nonlinear Finite Element Method Investigations

2020 ◽  
pp. 1-12
Author(s):  
Farzaneh Ahmadi ◽  
Ahmad Rahbar Ranji
Keyword(s):  
Finite Element ◽  
Crack Length ◽  
Ultimate Strength ◽  
Failure Modes ◽  
Great Influence ◽  
Longitudinal Crack ◽  
Nonlinear Finite Element ◽  
Geometrical Parameters ◽  
Rectangular Plates ◽  
Element Analysis

The main aim of present study was to determine the ultimate strength of cracked and corroded plates under uniform in-plane compression. Corrosion is considered as pitting-type corrosion at one side of the plate with a central longitudinal crack. Nonlinear finite element analysis using commercial computer code, ANSYS, is used to determine the ultimate strength of deteriorated plates. Different geometrical parameters, including the aspect ratio (AR) and thickness of the plate, number of pits, pit depth-to-thickness ratio, and crack length, are considered. It is found that the AR of plates have great influence on the ultimate strength of cracked-pitted plates. Because of the position and orientation of the crack, the length of central longitudinal crack has no influence on ultimate strength reduction of cracked and cracked-pitted plates. The results show that regardless of the number of pits and crack length, in thin plates where buckling controls failure modes at ultimate strength, the number of pits has less influence on reduction of the ultimate strength than thick plates where yielding controls failure mode. Also it is concluded that in rectangular plates, arrangements of pits has more effect on reduction of the ultimate strength of cracked-pitted plates than the number of pits.

The Detection Research of Tension about Vertical Prestressed Fine Rolled Twisted Bar in Box-Girders Construction of Civil Engineering

2012 ◽  
Vol 568 ◽  
pp. 134-137
Author(s):  
Xing Yuan Lin ◽  
Yan Feng Wu ◽  
Wei Wei Wang ◽  
Feng Zhang
Keyword(s):  
Prestressed Concrete ◽  
Civil Engineering ◽  
Tensile Force ◽  
Construction Process ◽  
Box Girders ◽  
Box Girder ◽  
Box Beam ◽  
Rigid Frame ◽  
Relationship Of ◽  
The Relationship

At present, vertical prestress detection is almost blank during box-girders construction of civil engineering . In order to effectively detect the effective tension at box-girder construction process in civil engineering based on the theory of structural dynamics, scene detection means, the relationship of box-girder vertical prestressing tensile force and dynamic characteristics of the exsertion segment reinforced was established. Vertical prestress of part of the box beam segments of a three-span prestressed concrete continuous rigid frame was detected , the shortcomings of the current vertical prestressing tensile force was analyzed . The results show that: the proposed method is direct, effective and able to effectively monitor the vertical prestressing tensile force. The research has important theoretical and engineering applications for crack prevention of box-girders.

scholarly journals A Finite Element Investigation into the Effect of Slope of Grain on Wood Baseball Bat Durability

2019 ◽  
Vol 9 (18) ◽  
pp. 3733 ◽  
Author(s):  
Joshua Fortin-Smith ◽  
James Sherwood ◽  
Patrick Drane ◽  
Eric Ruggiero ◽  
Blake Campshure ◽  
...  
Keyword(s):  
Finite Element ◽  
Wood Density ◽  
Wood Species ◽  
Parametric Study ◽  
Material Behavior ◽  
Finite Element Models ◽  
Ball Speed ◽  
Ball Impact ◽  
Fundamental Understanding ◽  
The Relationship

Bat durability is defined as the relative bat/ball speed that results in bat breakage, i.e., the higher the speed required to initiate bat cracking, the better the durability. In 2008, Major League Baseball added a regulation to the Wooden Baseball Bat Standards concerning Slope-of-Grain (SoG), defined to be the angle of the grain of the wood in the bat with respect to a line parallel to the longitudinal axis of the bat, as part of an overall strategy to reverse what was perceived to be an increasing rate of wood bats breaking into multiple pieces during games. The combination of a set of regulations concerning wood density, prescribed hitting surface, and SoG led to a 30% reduction in the rate of multi-piece failures. In an effort to develop a fundamental understanding of how changes in the SoG impact the resulting bat durability, a popular professional bat profile was examined using the finite element method in a parametric study to quantify the relationship between SoG and bat durability. The parametric study was completed for a span of combinations of wood SoGs, wood species (ash, maple, and yellow birch), inside-pitch and outside-pitch impact locations, and bat/ball impact speeds ranging from 90 to 180 mph (145 to 290 kph). The *MAT_WOOD (MAT_143) material model in LS-DYNA was used for implementing the wood material behavior in the finite element models. A strain-to-failure criterion was also used in the *MAT_ADD_EROSION option to capture the initiation point and subsequent crack propagation as the wood breaks. Differences among the durability responses of the three wood species are presented and discussed. Maple is concluded to be the most likely of the three wood species to result in a Multi-Piece Failure. The finite element models show that while a 0°-SoG bat is not necessarily the most durable configuration, it is the most versatile with respect to bat durability. This study is the first comprehensive numerical investigation as to the relationship between SoG and bat durability. Before this numerical study, only limited empirical data from bats broken during games were available to imply a qualitative relationship between SoG and bat durability. This novel study can serve as the basis for developing future parametric studies using finite element modeling to explore a large set of bat profiles and thereby to develop a deeper fundamental understanding of the relationship among bat profile, wood species, wood SoG, wood density, and on-field durability.

Study on Numerical Methodologies for Assessing Ultimate Bending Moment of Ship Hull Girder

2016 ◽  
Author(s):  
Ming Cai Xu ◽  
Zhao Jun Song
Keyword(s):  
Finite Element ◽  
Dynamic Analysis ◽  
Ultimate Strength ◽  
Bending Moment ◽  
Finite Element Models ◽  
Element Analysis ◽  
Hull Girder ◽  
Computer Resource ◽  
Explicit Dynamic ◽  
Convergence Of Solution

Nonlinear finite element analysis is usually used to assess the ultimate strength of hull girder, which includes implicit analysis and explicit dynamic analysis. So far, most of researchers use the implicit analysis to assess the ultimate strength of various vessels or stiffened plates. Comparing with the implicit analysis, the explicit dynamic analysis may be more stable since this method doesn’t need to consider the convergence of solution, and can consider the transient influence of time. However, the accuracy of solution results and time in the explicit dynamic method is very important. This depends on modelling configurations, such as the loading time, geometric ranges of finite element models, element types and applying methods of loading. The purpose of the present paper is to investigate the influences of these factors, and then to figure out a reliable numerical method which meets permitted accuracy and consumes acceptable computer resource in explicit dynamic analysis.

Study on Numerical Simulation of Projectile Penetrating UHMWPE Fiber Layers and Effects of Projectile Parameters

2012 ◽  
Vol 630 ◽  
pp. 121-126
Author(s):  
Gong Wu Huang ◽  
Ai Jun Chen ◽  
Shao Min Luo ◽  
Cheng Xu
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
High Speed ◽  
Research Approach ◽  
Finite Element Models ◽  
Uhmwpe Fiber ◽  
Penetration Ability ◽  
The Relationship ◽  
Better Than ◽  
Good Agreement

Finite element models of bullet penetrating UHMWPE fiber layers are established to study the relationship between parameters of projectile and penetration ability using LS-DYNA software. The numerical simulation results of penetration calculated in Lagrange algorithm are in good agreement with the real experimental results, which verify the validity of the finite element models and algorithm. The numerical results show that high speed and small angle of attack can improve the penetration ability, the penetration ability of oval projectile is better than flat head projectile. A valid and reliable research approach for evaluating the design of protective equipment and efficiency of projectiles are proposed.

EVALUATING THE EFFECT OF VARIOUS MENISCAL ATTACHMENTS AND MATERIAL PROPERTIES ON FEMORAL BONE STRESS

2018 ◽  
Vol 21 (01) ◽  
pp. 1850003
Author(s):  
Lance L. Frazer ◽  
Kenneth J. Fischer
Keyword(s):  
Finite Element ◽  
Material Property ◽  
Material Properties ◽  
Finite Element Models ◽  
Femoral Bone ◽  
Bone Stress ◽  
Stifle Joint ◽  
Meniscal Attachments ◽  
Property Changes ◽  
The Relationship

In this paper, several finite element models of an equine stifle joint with varying meniscal properties and attachments are compared to understand the effects of meniscal attachment complexity and material property changes on bone stresses. We found that the complexity in the meniscal attachment is critical when evaluating tensile stresses in the bone. We also demonstrate that simplified material properties may be justified when the relationship between each material property and the desired output variables is well understood. The choice of the most efficient, and yet appropriate, meniscal modeling method depends on the goals of the model.

Patient-specific spine models. Part 1: Finite element analysis of the lumbar intervertebral disc—a material sensitivity study

2002 ◽  
Vol 216 (5) ◽  
pp. 299-314 ◽  
Author(s):  
M J Fagan ◽  
S Julian ◽  
D J Siddall ◽  
A M Mohsen
Keyword(s):  
Finite Element ◽  
Intervertebral Disc ◽  
Material Properties ◽  
Intervertebral Discs ◽  
Basic Material ◽  
Patient Specific ◽  
Finite Element Models ◽  
Torsional Loading ◽  
Non Linear ◽  
Linear Material

If patient-specific finite element models of the spine could be developed, they would offer enormous opportunities in the diagnosis and management of back problems. Several generic models have been developed in the past, but there has been very little detailed examination of the sensitivity of these models' characteristics to the input parameters. This relationship must be thoroughly understood if representative patient-specific models are to be realized and used with confidence. In particular, the performance of the intervertebral discs are central to any spine model and need detailed investigation first. A generic non-linear model of an intervertebral disc was developed and subjected to compressive, flexion and torsional loading regimes. The effects of both material and geometric non-linearities were investigated for the three loading schemes and the results compared with experimental data. The basic material properties of the fibres, annulus and nucleus were then varied and the effects on the stiffness, annulus bulge and annulus stresses analysed. The results showed that the non-linear geometry assumption had a significant effect on the compression characteristics, whereas the non-linear material option did not. In contrast, the material non-linearity was more important for the flexural and torsional loading schemes. Thus, the inclusion of non-linear material and geometry analysis options in finite element models of intervertebral discs is necessary to predict in vivo load-deflection characteristics accurately. When the influence of the material properties was examined in detail, it was found that the fibre properties did not have a significant effect on the compressive stiffness of the disc but did affect the flexural and torsional stiffnesses by up to ±20 per cent. All loading modes were sensitive to the annulus properties with stiffnesses varying by up to ±16 per cent. The model also revealed that for a particular compressive deformation or flexural or torsional rotation, the disc bulge was not sensitive to any of the material properties over the range of properties considered. The annulus stresses did differ significantly as the material properties were varied (up to 70 per cent under a compressive load and 60 per cent during disc flexion).

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