scholarly journals Straight and Bent Bars Buckling Considered as the Axial Displacement of One Bar End

2020 ◽  
Vol 3 (1) ◽  
pp. 57-70
Author(s):  
Stefan Berczyński ◽  
Paweł Dunaj ◽  
Zenon Grządziel
Keyword(s):  
Finite Element ◽  
Compressive Force ◽  
Experimental Tests ◽  
Axial Displacement ◽  
New Approach ◽  
Finite Element Software ◽  
Bar Buckling ◽  
Energy Equations

AbstractA new approach has been taken to the problem of straight and bent bar buckling, where bar buckling is considered as a function of axial displacement of one end. It was assumed that the length of a bar being buckled at any instant of buckling is the same as that of a straight bar, regardless of the size of axial displacement of one end of the bar. Based on energy equations, a formula was derived for the value of axial displacement of one bar end or buckling amplitude in the middle of bar length as a function of compressive force. The established relationships were confirmed by simulation tests using the finite element software Midas NFX and by experimental tests.

Analysis of Jib Strength and Broken Jib Accident of High Pedestal Jib Crane from the Perspective of Mechanics

2012 ◽  
Vol 164 ◽  
pp. 322-325 ◽  
Author(s):  
Qing Dun Zeng ◽  
Fang Liu
Keyword(s):  
Finite Element ◽  
Working Conditions ◽  
Tensile Force ◽  
Compressive Force ◽  
Guangdong Province ◽  
Solid Model ◽  
Finite Element Software ◽  
Actual Working

According to an example of the broken jib accident of a high pedestal jib crane (HM2564) in a Shipyard Co., Ltd. in Guangdong province, this paper used a finite element software ANSYS to establish a solid model for the jib frame of the crane, calculated the stresses of jib system under various actual working conditions and checked the strengths. Simultaneously, the reasons of broken jib were quantitatively analyzed from the perspective of mechanics. The results show that the strengths of the jib system meet the requirements of safe use under all kinds of working conditions, but the related hoistman incorrectly operated the facility, cables can’t be winded normally in pulleys, thus resulting in that the tensile force of a cable was directly applied on the main jib by pulley spindle and the failure of the jib frame occurred under heavy compressive force of lifting cables.

Modeling NiTi Superelastic-Shape Memory Antagonistic Beams: A Finite Element Analysis

2009 ◽  
Author(s):  
Majid Tabesh ◽  
Mohammad Elahinia ◽  
Mehdi Pourazady
Keyword(s):  
Finite Element ◽  
Body Temperature ◽  
Shape Memory ◽  
Pedicle Screws ◽  
Experimental Tests ◽  
Element Analysis ◽  
Major Drawback ◽  
Screw Design ◽  
Finite Element Software ◽  
Engineering Sciences

Shape memory alloys (SMA) have received widespread attention from researchers in various fields of engineering sciences due to their exceptional properties of shape memory and superelasticity. NiTi equiatomic alloys among other SMA, show acceptable biocompatibility to be implemented in biomedical applications. Applications of NiTi in biomedical areas specifically orthopedics, demonstrate its unique performance which is not achievable with conventional materials. Pedicle screws, which are used as an anchoring point for implanting spinal instrumentations in spinal fracture and deformity treatments, entail a major drawback; i.e. loosening and back-out. The strength of screw contact with the surrounding bone diminishes as the bone degrades due to osteoporosis. A “Smart” pedicle screw design was developed to address this issue which uses NiTi superelastic-shape memory coils wrapped around it. The smart assembly consists of external superelastic tubing which is responsible for expanding the designed protrusions when they reach body temperature; also an internal shape memory wire inserted into the tubing is sought to retract the assembly when locally heated to above body temperature. The whole assembly was modeled as a beam structure in COMSOL Multiphysics Finite Element software. The behavior of shape memory alloy was defined in the software via its Partial Differential Equation (PDE) module. The SMA model has is a Tanaka-based model and is capable of capturing shape memory effect, superelasticity and hysteresis behavior, and partial transformation in both positive and negative directions. This 1D model was further modified to be included in a 3D framework such that it makes it possible for simulation of a beam under bending. The functionality of the smart screw design can be studied via this FEM model as a future work and the outcomes of the simulation can be compared with experimental tests on the prepared sample of the screw comprising NiTi tubing and wires.

Numerical study of the stand-off distance and liner thickness effect on the penetration depth efficiency of shaped charge process

2018 ◽  
Vol 233 (3) ◽  
pp. 977-986 ◽  
Author(s):  
P Dehestani ◽  
AR Fathi ◽  
HR Mohammadi Daniali
Keyword(s):  
Finite Element ◽  
Penetration Depth ◽  
Numerical Study ◽  
Experimental Tests ◽  
Shaped Charge ◽  
Thickness Effect ◽  
Geometrical Parameters ◽  
Element Analysis ◽  
Finite Element Software ◽  
Jet Penetration

The aim of this paper is to investigate the effect of geometrical parameters on the performance of jet penetration in the process of shaped charge. To this end, the finite element analysis was used to simulate the process. The simulated process was validated by experimental tests and the effect of some parameters including stand-off distance and the liner thickness on the jet penetration depth was studied. The results indicated that choosing the optimal distance between the liner and the target (stand-off distance) can significantly affect the performance of jet penetration in the target. In addition, examining the effect of liner thickness on the penetration depth efficiency revealed that by decreasing the liner thickness, the jet penetration depth on the target increases. It should be noted that ABAQUS finite element software was used in this simulation to analyze the process of shaped charge.

New Approach to Treat Broken Pile in Cast-In Site Bored Pile

2013 ◽  
Vol 639-640 ◽  
pp. 615-618
Author(s):  
Guang Hui Wang ◽  
Cheng Long Wei
Keyword(s):  
Finite Element ◽  
Cement Paste ◽  
New Combination ◽  
Analysis Model ◽  
New Approach ◽  
Finite Element Software ◽  
Bored Pile ◽  
Bore Pile ◽  
Combination Approach ◽  
Set Up

Many cast-in-site bore pile have broken pile because of collapsing in wall of holl. Based on the principle of mechanics, a new combination approach was proposed for dealing with the broken pile. The approach is displacing the soil in the pile by cement paste and increasing the height and the steal ratio of the top beam which is on the defect pile. Using the finite element software, we have set up the analysis model of the approach, which helps to demonstrate the rationality of this method. This method can be referenced by the reinforcement and maintenance of the bridges.

Research on Temperature Field of Variable Frequency Motor

2013 ◽  
Vol 273 ◽  
pp. 355-359
Author(s):  
Yao Hui Wu ◽  
Xiao Mei Liu ◽  
Xiu Feng Meng ◽  
Hong Tu Zhao
Keyword(s):  
Finite Element ◽  
Temperature Field ◽  
Induction Motor ◽  
Temperature Rise ◽  
Experimental Tests ◽  
Transient Temperature ◽  
Variable Frequency ◽  
Element Analysis ◽  
Finite Element Software ◽  
Frequency Power

To the problem of small induction motor that supplied by Variable frequency power temperature rise, according to the basic theory of heat transfer and using finite element analysis software, in the paper, it established a motor of two-dimensional transient temperature field model ,though the equivalent simplify of the structure and thermal conductivity, and the compare between the simulation of finite element software studies and the temperature experimental tests , It confirms the affect that variable frequency power on the motor temperature rise, and finds a simplified simulation of motor temperature field and parameters equivalent approach which do provide effective help to the design and use of the induction motor.

A New Approach for Predicting Residence Time Distribution of Subsurface Wastewater Infiltration System

2012 ◽  
Vol 518-523 ◽  
pp. 1720-1723
Author(s):  
Jin Feng Dong ◽  
Yue Zhang ◽  
Wei Yu Zhang
Keyword(s):  
Finite Element ◽  
Residence Time ◽  
Time Distribution ◽  
Residence Time Distribution ◽  
Design Stage ◽  
Design Parameters ◽  
Two Dimensional ◽  
Hydraulic Residence Time ◽  
New Approach ◽  
Finite Element Software

Hydraulic residence time (HRT) is one of the key design parameters controlling the removal efficiency of contaminants and nutrients in subsurface wastewater infiltration system (SWIS). A two-dimensional axisymetric finite element software called SEEP/W was used to simulate unsaturated and saturated flow within SWIS. The paper presents a methodology by example for estimating residence time distribution (RTD) at the design stage of SWIS.

Error Localization Methods With Static Modes and Thermographic Data

1995 ◽  
Author(s):  
F. Thouverez ◽  
L. Humbert ◽  
L. Jezequel
Keyword(s):  
Finite Element ◽  
Experimental Tests ◽  
Physical Parameters ◽  
Actual Structure ◽  
New Approach ◽  
Knowledge Models ◽  
Error Localization ◽  
Expansion Technique ◽  
Principal Strains ◽  
Do So

Abstract The goal of updating methods in dynamic is to improve the finite element models by means of experimental tests. In fact, we try to estimate a better value of the mass (M) and stiffness (K) matrices. Several ways are possible to complete the updating of M and K : - Global techniques which consist to correct the entire matrices without keeping a physical meaning of the M and K modifications. This approach transforms the finite element “knowledge” models into “representation” models which are more accurate in the measured frequency range but don’t represent the actual structure. This kind of method has been developed first by Baruch (1978) and Berman (1979) and improved by lots of researchers (Kabe, 1985 and Wei, 1990). - Local techniques try to compute the best values of the physical parameters defined on each element of the modelling. This method is a very stiff one since the optimization of the numerical modes is required over a very large number of parameters. To be able to use this approach we must select only the elements which must be modified to reduce the size of the optimization problem. To do so, we will apply the localization methods. In this paper we will present two ways to locate the modelling errors as well as a new approach based on thermographic, data. Each localization methods will be tested and we will show the influence of the expansion technique and the improvement due to the use of the static modes. The thermographic measurements give us a large number of data but partial because the information gathered by the camera concernes only the sum of the principal strains (Olivier et al, 1988 and Ryall et al, 1992). But the advantages of this method are the number of points which is important and the nature of the data which is a strain information (very sensitive to the local defaults of modelling).

The Intersection Method: A New Approach on the Concrete Aggregate Model

2010 ◽  
Vol 163-167 ◽  
pp. 1053-1057
Author(s):  
Jian Liang ◽  
Zong Ke Lou
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Numerical Study ◽  
Concrete Aggregate ◽  
Aggregate Model ◽  
New Approach ◽  
Finite Element Software ◽  
User Friendly ◽  
Intersection Method

In order to study the meso-structure of concrete deeply, this paper proposes a new approach—intersection method, which is much simpler and more applicable to check the interference for wide varieties of shape aggregate by using the VBA language built-in AUTOCAD. Results show that the procedure to establish the model of concrete aggregate is user-friendly, simple, intuitive and precise. It can be analyzed through introducing into finite element software for the further numerical study of macro and micro mechanical properties of concrete by using the mutual files SAT which is used to exchange the CAD data between AUTOCAD and other software.

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