Analysis on the Critical Buckling Stress in the TC4 Thin Plate Weldment

2011 ◽  
Vol 704-705 ◽  
pp. 1387-1392
Author(s):  
Xiu Ling Qi ◽  
Yong Zhang
Keyword(s):  
Compressive Stress ◽  
Thin Plate ◽  
Empirical Equation ◽  
Analytic Solution ◽  
Critical Value ◽  
Theoretical Formula ◽  
Buckling Stress ◽  
Longitudinal Residual Stress ◽  
Uneven Heating ◽  
Buckling Distortion

There exists a large amount of longitudinal tensile stress in the weld bead of the TC4 thin plate for the uneven heating of the welding thermal resource. Owing to the equilibrium of the internal stress, longitudinal compressive stress is also large on the edge of the thin plate. When the compressive stress is larger than the critical buckling stress, the buckling distortion can take place. Therefore, the value of the critical buckling stress is important to judge the distortion. Some theoretical formula and empirical equation can not give the suitable solution to the judge of the critical value of the certain TC4 thin plate weldment because of the difficulty in the analytic solution and difference in the feature of the material and boundary condition. Finite element method was utilized to estimate the value of the buckling stress in the thin plate. Based on the solution, the adjustment of welding longitudinal compressive stress model is done. Henceforth, the critical buckling stress can be determined by the method. Keywords: critical buckling stress, TC4 thin plate, welding longitudinal residual stress

Experimental Verification of Distortion Analysis of Welded Stiffeners

2002 ◽  
Vol 18 (04) ◽  
pp. 216-225
Author(s):  
M. V. Deo ◽  
P. Michaleris
Keyword(s):  
Experimental Verification ◽  
Experimental Validation ◽  
Welding Process ◽  
Computational Results ◽  
Buckling Mode ◽  
Fea Model ◽  
Buckling Stress ◽  
Distortion Analysis ◽  
Process Simulations ◽  
Buckling Distortion

This paper presents an experimental verification for the predictive distortion analysis approach proposed in Michaleris & DeBicarri (1996,1997) and Vanli & Michaleris (2001) for welded T-type stiffeners. The predictive technique employing the decoupled 2-D and 3-D approach is used for the prediction of buckling distortion and the magnitude of bowing distortion. Two-dimensional thermo-mechanical welding process simulations are performed to determine the residual stress. The critical buckling stress along with the buckling mode are computed in 3-D eigenvalue analyses. Large deformation analyses are carried out to predict the magnitude of bowing distortion. Experimental validation of the prediction is carried out in the lab. Welding experiments are carried out using welding conditions identical to those used in the FEA model. The computational results are then verified with experimental observations

Nonlinear Stability Analysis of Elastic Cylinders under Global Bending

2014 ◽  
Vol 638-640 ◽  
pp. 1754-1757
Author(s):  
Lei Chen
Keyword(s):  
Compressive Stress ◽  
Geometric Nonlinearity ◽  
Failure Behavior ◽  
Nonlinear Stability Analysis ◽  
Pure Bending ◽  
Buckling Strength ◽  
Buckling Stress ◽  
Bifurcation Buckling ◽  
Elastic Cylinders ◽  
Axial Compressive Stress

The cylindrical shells under global bending with different geometric parameters display different failure behavior. The size of typical buckles under axial compressive stress regimes is rather small and extends over a very small zone, with the axial compressive stress reaching the critical value. The first estimate of the elastic buckling strength in bending is the condition in which the most compressed fiber reaches the buckling stress for uniform axial compression. For short cylinders, local bifurcation buckling occurs at the middle of the most compressed side of the shell, and geometric nonlinearity has a little effect on the buckling strength, while for medium-length and long cylinders, the geometric nonlinearity and the ovalization of the cross-section should be considered. This paper explores the failure behavior in elastic cylinders in pure bending.

Wrinkling of Thin Membrane Under Thermal Loading

2006 ◽  
Author(s):  
Jia Gao ◽  
Seungbae Park ◽  
James Pitarresi ◽  
Dorel Homentcovschi
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Compressive Stress ◽  
Critical Value ◽  
Thin Membrane ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Post Buckling ◽  
Formation And Evolution ◽  
Wrinkle Generation

There has been an increasing interest in the applications of thin membrane in space application, flexible electronic display, manufacturing of glass displays and growth of film on materials at elevated temperatures. Because of the negligible bending stiffness of thin membranes, membranes are lack of resistance to compressive stress. For the applications at high temperatures, the thermal expansion coefficient mismatch between membrane and substrate materials may generate compressive stress that causes the membrane buckling. The study of thermal buckling of isotropic elastic plate in the context of the large - deflection theory was the subject of a series of papers[1-5]. However, it has been noted that none of these papers has considered the second buckling of the membrane resulting in membrane wrinkling. The presence of wrinkles may significantly change deflection and stress profile of membranes. So, it is important to develop an effective analysis method to investigate the wrinkle formation and evolution in membrane subjected the elevated temperature. This paper presents the experiment work to investigate wrinkle formation and evolution in membranes heated from room temperature up to 170 °C. The specimens consist of polymer and metal membranes with steel and silicon substrate respectively. A wide range of membrane shapes and aspect ratios are considered in this work. An experiment set up is developed to study the deflection profiles of membranes at discrete temperatures. The information gained from this experiment work is used to validate numerical modeling results. The Finite Element Analysis results using nonlinear post-buckling analysis are also included in this paper. The nonlinear post-buckling analysis provides a good understanding of the mechanism of wrinkle generation and evolution as temperature increased. It is shown that the first buckling of membrane significantly reduces bending stiffness thus to create localized buckling modes accounting for the wrinkle generation. The wrinkle pattern is stable until the temperature reaches the next critical value. After this critical temperature, the wrinkle pattern is changed until temperature reaches the next critical value. The new wrinkle pattern is keeping evolved until the final temperature is reached. The finite element analysis results are in good agreement with experimental observations.

Reinforcing Function of Polymer Cords Embedded in Rubber under Compression

1992 ◽  
Vol 20 (4) ◽  
pp. 254-264 ◽  
Author(s):  
X. W. Du ◽  
W. Qu ◽  
Z. M. Wan ◽  
H. Ma ◽  
M. Yao ◽  
...  
Keyword(s):  
Compressive Stress ◽  
Volume Fraction ◽  
Failure Stress ◽  
Experimental Results ◽  
The Other ◽  
Composite Specimen ◽  
Small Range ◽  
Buckling Stress ◽  
Other Hand ◽  
Rubber Composite

Abstract Whether polymer cords embedded in rubber under compression have a reinforcing function is still an important question in the analysis of tire structures. In this paper, on the basis of experimental results, it is confirmed that polymer cords embedded in rubber present some stiffness, thus playing a reinforcing role to a certain extent. When the cord volume fraction in the cord-rubber composite is sufficiently large, the reinforcing function of the polymer cords is so significant that the properties of the cord-rubber composite are mainly influenced by those of the cord. When the compressive stress reaches a certain value, the cord-rubber composite specimen yields by buckling if the cord volume fraction is large enough and the cord angle is within a certain small range. The buckling stress, which may be considered to be a failure stress, decreases with an increase in temperature. On the other hand, the effect of the cord angle on the buckling stress is found to be insignificant.

Buckling of Rectangular Plates under Bi–Axial Compression

1955 ◽  
Vol 59 (536) ◽  
pp. 566-568 ◽  
Author(s):  
J. S. Przemieniecki
Keyword(s):  
Compressive Stress ◽  
Axial Compression ◽  
Rapid Decrease ◽  
Rectangular Plates ◽  
Side Ratio ◽  
Buckling Stress ◽  
Compressive Stresses ◽  
Isotropic Plates ◽  
Stress Coefficient ◽  
Edge Conditions

The problem of the buckling under bi-axial compression is considered for flat rectangular isotropic plates with simple edge conditions and no lateral restraint. The buckling stress coefficient is plotted against the side ratio for various conditions of edge restraint and a known compression or tension on the sides of the plate. It is found that there is some reduction in the buckling stress if the sides of the plate are subjected to compressive stresses and, conversely, there is an increase for tensile stresses. Furthermore, for plates with large side ratios, there is a rapid decrease of the spanwise buckling stress as the chordwise compressive stress approaches its appropriate Euler instability value.

Dynamic Response of Polymer Based Shear Stiffening Composite

2014 ◽  
Vol 626 ◽  
pp. 323-328
Author(s):  
Shan Qing Xu ◽  
Dong Ruan ◽  
Jason Miller ◽  
Igor Sbarski ◽  
Ajay Kapoor
Keyword(s):  
Dynamic Response ◽  
Strain Rate ◽  
Compressive Stress ◽  
Storage Modulus ◽  
Critical Value ◽  
Angular Frequency ◽  
Strain Rates ◽  
Sweep Frequency ◽  
Rheological Study ◽  
Compressive Response

In this paper, the uniaxial dynamic compressive response and rheological properties of a newly developed commercially available polymer based shear stiffening (PSS) composite is experimentally studied at different crushing velocities. The results showed that the compressive stress of PSS composites increases with the rising strain rates. Comparing the stress-strain curves of PSS composites and neoprene at the same strain rate, it was found that the compressive stress of PSS composite increased gradually with strain, while the compressive stress of neoprene increased sharply with strain. The uniaxial dynamic mechanical analyses of PSS composites showed that storage modulus of PSS composite increased with the increase of sweep frequency. The rheological study of PSS composites showed that the storage modulus of PSS composite significantly increased when the angular frequency was higher than a critical value, e.g., 100 rad/s, demonstrating evident shear stiffening properties.

Effects of Web Height-Thickness Ratio on Longitudinal Residual Stresses of the Welded Monosymmetric I-Section

2013 ◽  
Vol 671-674 ◽  
pp. 446-449
Author(s):  
Zhuang Nan Zhang ◽  
Ya Nan Zhao ◽  
Lu Jin
Keyword(s):  
Tensile Stress ◽  
Compressive Stress ◽  
Thickness Ratio ◽  
Residual Compressive Stress ◽  
Residual Tensile Stress ◽  
Stress Distributions ◽  
Distribution Width ◽  
Longitudinal Residual Stress ◽  
Increasing Trends ◽  
Peak Value

This paper descries work carried out using ANSYS finite element techniques to evaluate the longitudinal residual stress distributions of the welded monosymmetric I-section in various web height-thickness ratios. From the analysis results, it is shown that, with the web height to thickness ratio increased, the peak values of residual tensile and compressive stress in flange decrease, and the peak residual tensile stress in web decrease too, but the peak residual compressive stress increase. Meanwhile, the distribution width of residual tensile stress in flange and the distribution width of residual compressive stress in web all present increasing trends. The magnitude of the maximum longitudinal residual tensile stresses in both the flange and web reach the yield stress fy, while the maximum residual compressive stress in wide and narrow flange is close to 0.4 fy and 0.3 fy respectively, and the peak value of compressive stress in web which closes to the wide flange and to the narrow flange is about 0.4fy and 0.3fy separately. With the change of height to thickness ratio of web, the distributive width of residual tensile stress in flange or web is about 0.3 times of flange width or web height.

Sign in / Sign up

Export Citation Format

Share Document