scholarly journals Plastic Deformation of Metal Tubes Subjected to Lateral Blast Loads

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Kejian Song ◽  
Yuan Long ◽  
Chong Ji ◽  
Fuyin Gao
Keyword(s):  
Mathematical Model ◽  
Plastic Deformation ◽  
Plastic Flow ◽  
Cross Section ◽  
Circular Tube ◽  
Circular Tubes ◽  
Simply Supported ◽  
Different Dimensions ◽  
Thin Walled ◽  
Wave Induced

When subjected to the dynamic load, the behavior of the structures is complex and makes it difficult to describe the process of the deformation. In the paper, an analytical model is presented to analyze the plastic deformation of the steel circular tubes. The aim of the research is to calculate the deflection and the deformation angle of the tubes. A series of assumptions are made to achieve the objective. During the research, we build a mathematical model for simply supported thin-walled metal tubes with finite length. At a specified distance above the tube, a TNT charge explodes and generates a plastic shock wave. The wave can be seen as uniformly distributed over the upper semicircle of the cross-section. The simplified Tresca yield domain can be used to describe the plastic flow of the circular tube. The yield domain together with the plastic flow law and other assumptions can finally lead to the solving of the deflection. In the end, tubes with different dimensions subjected to blast wave induced by the TNT charge are observed in experiments. Comparison shows that the numerical results agree well with experiment observations.

Free Vibration of Thin-Walled Open Section Beams With Unconstrained Damping Treatment

1981 ◽  
Vol 48 (1) ◽  
pp. 169-173 ◽  
Author(s):  
S. Narayanan ◽  
J. P. Verma ◽  
A. K. Mallik
Keyword(s):  
Free Vibration ◽  
Cross Section ◽  
Transverse Vibration ◽  
Natural Frequencies ◽  
Vibration Characteristics ◽  
Numerical Results ◽  
Simply Supported ◽  
Clamped Beams ◽  
Thin Walled ◽  
Open Cross Section

Free-vibration characteristics of a thin-walled, open cross-section beam, with unconstrained damping layers at the flanges, are investigated. Both uncoupled transverse vibration and the coupled bending-torsion oscillations, of a beam of a top-hat section, are considered. Numerical results are presented for natural frequencies and modal loss factors of simply supported and clamped-clamped beams.

Two Secondary Effects in Bending of Slit Thin-Walled Tubes

1966 ◽  
Vol 33 (1) ◽  
pp. 75-78 ◽  
Author(s):  
F. P. J. Rimrott
Keyword(s):  
Cross Section ◽  
Circular Tube ◽  
Bending Moment ◽  
Approximate Equation ◽  
Neutral Axis ◽  
Secondary Effects ◽  
Theoretical Predictions ◽  
Thin Walled ◽  
Brazier Effect ◽  
Free Edges

During bending of a slit, thin-walled circular tube two secondary effects are observed to occur simultaneously. One, the so-called Brazier effect, occurs in thin-walled tubes generally when they are subjected to bending, and consists of an ovaling of the cross section. The second effect is a peculiarity of slit tubes only and manifests itself as an overlap of the free edges. The severity of both effects depends upon the location of the slit. The bending moment and the radial and tangential displacements have been determined as function of the curvature for four different slit locations with respect to the neutral axis. The value of the curvature at instability has also been derived. Subsequently an approximate equation has been obtained for the cantilever. The results of experiments on a cantilever are compared with the theoretical predictions.

Shear Buckling of Clamped and Simply-Supported Infinitely Long Plates Reinforced by Closed-Section Transverse Stiffeners

1962 ◽  
Vol 13 (3) ◽  
pp. 212-222 ◽  
Author(s):  
I. T. Cook ◽  
K. C. Rockey
Keyword(s):  
Circular Tube ◽  
Flexural Rigidity ◽  
Torsional Rigidity ◽  
Numerical Results ◽  
Rectangular Plates ◽  
Simply Supported ◽  
Shear Buckling ◽  
Thin Walled ◽  
The Individual

SummaryThe paper presents a solution to the buckling of infinitely long plates when they are reinforced by transverse stiffeners possessing both torsional and flexural rigidity. The cases of both edges being clamped and simply-supported are dealt with. Numerical results are presented for the ratio of torsional rigidity to flexural rigidity as obtained with a thin-walled circular tube. When the stiffeners are completely rigid, in which case the individual panels are clamped along the transverse edges, the results obtained are in agreement with existing solutions for isolated rectangular plates.

Study of strain-stress state of flat knives for cutting thin-walled pipes

2021 ◽  
Vol 77 (9) ◽  
pp. 1039-1046
Author(s):  
S. P. Eron’ko ◽  
E. V. Oshovskaya ◽  
O. A. Kovaleva
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Stress State ◽  
Mathematical Simulation ◽  
Cross Section ◽  
Cutting Tool ◽  
Small Diameter ◽  
Pipe Welding ◽  
Strain Stress ◽  
Thin Walled

Cutting of pipes into measured lengths on-line of pipe welding mill by disc saws and by facilities of abrasive cutting requires special measures of safety of personal. Besides, the necessity of frequent change of cutting instrument results in losses of production time. To eliminate the drawbacks, a study was initiated related to creation of shears which could enable to accomplish a quality transverse cutting of thin-walled pipes of small diameter by flat knives with various form of the working edges. A methodology and the results of study of strain-stress state of flat knives with application of physical and mathematical simulation of the process of transverse cutting of thin-walled pipes of small diameter presented. At the physical simulation using a polarization-optical installation, the pictures of deformation centers arising in the lower part of the knife in the zone of contact of its cutting edges with the body of the hollow circular profile being cut by it were obtained. In the experiment, models of three types of knives made of organic glass on a scale of 1:1 were used. Cutting edges of the knives for cutting pipes of 25 mm outer diameter, wall thickness of 2 mm were wedge-shaped, convex semicircular and concave. The data from studies of the loaded state of transparent knife models served as the basis for mathematical simulation of the strain-stress state of the shears cutting tool in the SolidWork application package using a strength analysis module that implements the finite element method in the form of tetrahedrons. The current values of the pipe cutting force used in the mathematical model were preliminarily calculated according to the previously proposed dependence, taking into account the strength of the hollow profile material and the area of the cut layer of its cross section for a given relative displacement of the cutting edges of the knife. The results of mathematical modeling were the pictures of deformations and equivalent stresses of the cutting part of the knife, determined according to the third theory of strength. A qualitative similarity has been established for the distribution patterns of stress fields recorded using the polarization-optical method on knife models and obtained in mathematical modeling for working samples of the shears cutting tool operated under the conditions of pipe welding mills. The proposed mathematical model makes it possible to estimate the values of the maximum equivalent stresses in the working part of a flat knife, taking into account the shape of its cutting edges, as well as the force required for cutting a thin-walled pipe into measured lengths with the corresponding dimensions of its cross-section and the strength of the material.

An Approach for Analysis of Bulged Profile and Thickness Distribution of Tube in Free Hydro-Bulging Process

2012 ◽  
Vol 499 ◽  
pp. 127-131
Author(s):  
Xiao Feng Liu ◽  
Lian Fa Yang ◽  
Yu Xian Zhang
Keyword(s):  
Mathematical Model ◽  
Plastic Deformation ◽  
Finite Element ◽  
Wall Thickness ◽  
Deformation Behavior ◽  
Thickness Distribution ◽  
Plastic Deformation Behavior ◽  
Thin Walled Tube ◽  
Thin Walled ◽  
Tubular Components

Tubular components are widely used in the areas of automotive and aerospace industries due to their excellent properties. A mathematical model considering the bulged region as a parabola curve is proposed to examine the plastic deformation behavior of a thin-walled tube during the free hydro-bulged process. The finite element simulations of the free hydro-bulging process are carried out to verify the approach indirectly. The results indicate that the model is accurate and acceptable to figure out the circumferential radius, wall thickness and axial radius of the bulged profile.

Optimization Design of Cross-Section of Prestressed Steel-Concrete Composite Box Girder

2011 ◽  
Vol 366 ◽  
pp. 207-210
Author(s):  
Jun Wang ◽  
Zi Qing Li ◽  
Xian Wu Hao
Keyword(s):  
Mathematical Model ◽  
Computer Program ◽  
Cross Section ◽  
Optimization Design ◽  
Box Girder ◽  
Nonlinear Constrained Optimization ◽  
Efficiency Optimization ◽  
Simply Supported ◽  
Design Specifications ◽  
Numerical Result

According to the design specifications and structure theories of prestressed steel-concrete composite box girder, a mathematical model of optimization of cross-section of prestressed steel-concrete composite box girder was established. The nonlinear constrained optimization was adopted and the computer program was compiled with Matlab language. The efficiency optimization was achieved in the optimization design of the two different span bridge cross-section of a simply supported steel-concrete composite box girder. Numerical result illustrated that the optimization mathematical model of optimization was exact and the algorithm effective.

Combined Tension-Torsion Tests for Aluminum Alloy 2S-O

1952 ◽  
Vol 19 (4) ◽  
pp. 496-500
Author(s):  
Aris Phillips
Keyword(s):  
Aluminum Alloy ◽  
Plastic Flow ◽  
Experimental Results ◽  
Plastic Deformations ◽  
Circular Tubes ◽  
Thin Walled ◽  
Stress Ratios ◽  
Theory Of Plastic Flow

Abstract In this paper ten combined tension-torsion tests with thin-walled circular tubes of aluminum alloy 2S-O are described. All specimens were loaded with variable stress ratios. It has been found that the theory of plastic flow represents the experimental results with much greater accuracy than does the theory of plastic deformations.

Response of Sandwich Panels with Tubular Cores to Blast Load

2014 ◽  
Vol 566 ◽  
pp. 581-585
Author(s):  
Steeve Chung Kim Yuen ◽  
Gerald Nurick ◽  
Misha C. du Plessis
Keyword(s):  
Plastic Deformation ◽  
Mild Steel ◽  
Sandwich Panels ◽  
Blast Load ◽  
Charge Mass ◽  
Circular Tubes ◽  
Back Face ◽  
Different Types ◽  
Cladding Panels ◽  
Thin Walled

This paper reports on the response of cladding sandwich panels with tubular cores to uniform blast load. The panels consist of thin-walled circular tubes (38 mm in diameter) made from aluminium 6063-T6 riveted laterally between the skin plates at varying spacing arrangements to provide four different types of panels. The skin exposed to the blast load is made from DOMEX 700 Steel while the back face skin is made from mild steel. Varying charge masses of explosive (ranging from 5 g to 40 g) with a prescribed load diameter of 40mm is detonated at a stand-off distance of 200 mm to provide a “uniform” blast load to the sandwich panels. Energy is dissipated mostly through the plastic deformation of the tubular cores. The results show an increase in average deflection with an increase in charge mass/impulse for the different types of panels. The cladding panels with the least interaction between the tubular cores are observed to have the highest energy absorption capabilities for a given charge mass.

scholarly journals Energy Absorption Characteristics of a CFRP-Al Hybrid Thin-Walled Circular Tube under Axial Crushing

Aerospace ◽  
2021 ◽  
Vol 8 (10) ◽  
pp. 279
Author(s):  
Rongchao Jiang ◽  
Zongyang Gu ◽  
Tao Zhang ◽  
Dawei Liu ◽  
Haixia Sun ◽  
...  
Keyword(s):  
Finite Element ◽  
Energy Absorption ◽  
Circular Tube ◽  
Finite Element Models ◽  
Axial Crushing ◽  
Circular Tubes ◽  
Absorption Performance ◽  
Thin Walled ◽  
Entropy Weighted ◽  
Absorption Characteristics

Thin-walled tubes have gained wide applications in aerospace, automobile and other engineering fields due to their excellent energy absorption and lightweight properties. In this study, a novel method of entropy-weighted TOPSIS was adopted to study the energy absorption characteristics of a thin-walled circular tube under axial crushing. Three types of thin-walled circular tubes, namely, aluminum (Al) tubes, carbon-fiber-reinforced plastics (CFRP) tubes and CFRP-Al hybrid thin-walled tubes, were fabricated. Quasi-static axial crushing tests were then carried out for these specimens, and their failure modes and energy absorption performance were analyzed. The CFRP material parameters were obtained through tensile, compression and in-plane shear tests of CFRP laminates. The finite element models for the quasi-static axial crushing of these three types of circular tubes were established. The accuracy of the finite element models was verified by comparing the simulation results with the test results. On this basis, the effects of the geometric dimension and ply parameters of a CFRP-Al hybrid thin-walled circular tube on the axial crushing energy absorption characteristics were studied based on an orthogonal design and entropy-weighted TOPSIS method. The results showed that Al tube thickness, CFRP ply thickness and orientation have great effect on the energy absorption performance of a CFRP-Al hybrid thin-walled circular tube, whereas the tube diameter and length have little effect. The energy absorption capability of a CFRP-Al hybrid tube can be improved by increasing the thickness of the Al tube and the CFRP tube as well as the number of ±45° plies.

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