Research on Structure Stress Analysis on Composite by Lock-In Thermography

2010 ◽  
Vol 150-151 ◽  
pp. 1649-1654
Author(s):  
Xun Liu ◽  
Jun Yan Liu ◽  
Jing Min Dai
Keyword(s):  
Composite Materials ◽  
Stress Concentration ◽  
Stress Distribution ◽  
Stress Analysis ◽  
Principal Stress ◽  
Mechanical Performance ◽  
Material Structure ◽  
Thermoelastic Effect ◽  
Component Structure ◽  
Lock In

The application of thermoelastic stress analysis in composite materials is particularly complicated because of the anisotropy of the material, which determines the thermoelastic effect to be depended on the material property and mechanical performance. This paper describes a theoretical and experimental analysis on full-filed stress distribution from thermoelastic measurements and its application to determination of stress concentration. The sum of the principal stress can be measured by Thermal Stress Analysis (TSA). Lock-in Thermography has been applied to measure the sum of principal stress distribution of component structure by its high thermal resolving. In this study, Experiments were carried out with GFRP composite ply and foam materials under cyclic load. The thermoelastic constant is obtained for GFRP and foam composite materials. The stress concentration is analyzed for a specimen with a hole. The experimental results show the stress distribution can be measured and analyzed using Lock-in thermography. It is found that the composite material structure stress can be evaluated with good accuracies by lock in thermography.

Research on High Strength Aluminum Alloys Components Stress Analysis by Lock-In Thermography

2010 ◽  
Vol 29-32 ◽  
pp. 2775-2780
Author(s):  
Xun Liu ◽  
Jun Yan Liu ◽  
Jing Min Dai
Keyword(s):  
Stress Concentration ◽  
Aluminum Alloys ◽  
Stress Distribution ◽  
Stress Analysis ◽  
Principal Stress ◽  
High Strength ◽  
Temperature Deviation ◽  
Component Structure ◽  
Lock In ◽  
High Strength Aluminum Alloys

This paper describes a theoretical and experimental analysis on full-filed stress distribution from thermoelastic measurements and its application to determination of stress concentration. The sum of the principal stress can be measured by Thermal Stress Analysis (TSA). Lock-in Thermography has been applied to measure the sum of principal stress distribution of component structure by its high thermal resolving. In this study, Finite element method is used to calculate the sum of principal stress distribution, and the thermoelastic effect model is developed to study the relationship between the temperature deviation and the applied stress in an elastic material. Experiments were carried out with ANSI 7071 high strength aluminum alloys ply and ones with a crack under cyclic load. The thermoelastic constant is obtained for ANSI 7071 high strength aluminum alloys materials. The stress concentration factor is calculated for a ply with modeling crack under the condition of different loads. The experiment was carried out with high strength aluminum alloys component structure with rivet joints. The experimental results show the stress distribution can be measured and analyzed the contact stress distribution between ply and rivet by using Lock-in thermography. It was found that the structure stress can be evaluated with good accuracies by the lock in thermography.

Analysis of Stress in Aircraft Components Using Lock-In Thermography

2010 ◽  
Vol 663-665 ◽  
pp. 1073-1076 ◽  
Author(s):  
Xun Liu ◽  
Jun Yan Liu ◽  
Xu Dong Li ◽  
Guang Yu Zhang
Keyword(s):  
Stress Concentration ◽  
Stress Distribution ◽  
Stress Analysis ◽  
Aluminium Alloys ◽  
Thermoelastic Effect ◽  
Load Frequency ◽  
Effect Theory ◽  
Lock In ◽  
The Relationship

This paper describes a theoretical and experimental analysis on full-filed stress distribution from thermoelastic measurements and its application to determination of stress concentration. The sum of the principle stress can be measured by Thermal Stress Analysis (TSA). Lock-in Thermography is very effective tool to measure the structure stress distribution by its high thermal resolving. In this study, the thermoelastic effect theory is described and the relationship between the temperature and the applied stress is developed in an elastic material. Experiments were carried out with 2A12 aluminium alloys plate and ones with hole structure under cyclic load. The thermoelastic effect coefficient is obtained for 2A12 aluminium alloys materials, and the effect law is analyzed that the stress value measured was affected by load frequencies. The optional load frequency is obtained, and that is, the load frequency is selected greater than 3.5Hz for 2Al12 materilas, and it was found that the structure stress can be evaluated with good accuracies by the lock in thermography. The experiment was carried out for aircraft components stress distribution measurement and structure stress analysis. The experimental results show the stress concentration position is easy found from stress distribution by lock-in thermography.

Study on Full-Field Stress Analysis for Composite Material Structure Using Lock-in Thermography

2011 ◽  
Vol 314-316 ◽  
pp. 1372-1376 ◽  
Author(s):  
Jun Yan Liu ◽  
Xun Liu ◽  
Yang Wang
Keyword(s):  
Stress Distribution ◽  
Stress Analysis ◽  
Composite Structure ◽  
Composite Structures ◽  
Experimental Results ◽  
Material Structure ◽  
Element Analysis ◽  
Thermoelastic Effect ◽  
Gfrp Composite ◽  
Lock In

This paper describes a set of theoretical and experimental results based on thermoelastic effect measurement from Glass-Fiber-Reinforced-Polymer (GFRP) composite structure for full-filed stress analysis. The sum of the principle stress (The first stress invariant) can be measured by means of thermoelastic stress analysis (TSA), and this method is used to determine the stress concentration of the composite structure. A finite element analysis is proposed to predict the stress distribution for GFRP gluing structure. The lock-in thermography has been applied to measure the structure stress distribution by its high thermal resolution. The experiment was carried out with different GFRP composite structures by lock in thermography. The experimental results show the stress distribution can be measured and evaluated with good accuracies by using of lock-in thermography

The Study on Stress Analysis of Compound Steel-Foam-Glass Fiber Reinforced Polymer (GFRP) Structure by Lock-in Thermography

2011 ◽  
Vol 80-81 ◽  
pp. 64-69 ◽  
Author(s):  
Jun Yan Liu ◽  
Xun Liu ◽  
Yang Wang
Keyword(s):  
Stress Distribution ◽  
Stress Analysis ◽  
Principal Stress ◽  
Mechanical Performance ◽  
Foam Glass ◽  
Experimental Result ◽  
Compound Structure ◽  
Periodic Load ◽  
Steel Foam ◽  
Lock In

The application of thermoelastic stress analysis in compound structure is particularly complicated because of the different material components, which determines the different thermoelastic effect to be depended on the different material property and mechanical performance. This paper describes a theoretical and experimental analysis on full-filed stress distribution from thermoelastic measurements and its application to determination of stress concentration for compound Steel-Foam-GFRP structure. A finite element modeling is proposed to calculate the sum of the principal stress under the condition of dynamic cyclic load. The sum of the principal stress can be measured by means of thermal stress analysis (TSA). Lock-in thermography has been applied to measure the sum of principal stress distribution of component by its high thermal resolution. In this study, Experiments were carried out with Steel-Foam-GFRP compound structure under dynamic periodic load. The thermoelastic constant is calibrated for different component of compound structure, respectively. An artificial neural network (ANN) is proposed to identify the different component stress distribution on whole compound structure. The experimental result shows that the stress distribution of compound structure can be measured and analyzed using lock-in thermography. It is found that the stress distribution of compound structure can be evaluated with good accuracies by lock-in thermography.

Research on the Problem of Stress Concentration Caused by the Strengthening Phase in the Nanocomposite Coating

2013 ◽  
Vol 816-817 ◽  
pp. 185-190
Author(s):  
Ling Chao Kong ◽  
Er Geng Zhang
Keyword(s):  
Body Size ◽  
Composite Materials ◽  
Stress Concentration ◽  
Stress Distribution ◽  
Nanocomposite Coating ◽  
The Finite Element Method ◽  
Strengthening Phase ◽  
Preliminary Calculation ◽  
The Matrix ◽  
Method Analysis

Using the finite element method analysis the influence of the enhanced body size to stress concentration factor and stress distribution between the enhanced body in nanocomposite coating and the matrix interface. By preliminary calculation, the paper predicts a trend that the stress distribution on the interface reduces with the decreases of the enhanced body size and the stress concentration. Theoretically proved the iomportant rule that in the field of organic composite materials if you want to improve the performance of composite materials ,the enhanced body size need to be reduced.

Some Problems Associated with Stress Concentration

1955 ◽  
Vol 59 (536) ◽  
pp. 551-561 ◽  
Author(s):  
H. L. Cox
Keyword(s):  
Stress Concentration ◽  
Stress Distribution ◽  
Stress Analysis ◽  
Elastic Stress ◽  
Fatigue Tests ◽  
Detailed Knowledge ◽  
Two Dimensional ◽  
Special Boundaries ◽  
The Third ◽  
Actual Strength

The theory of stress concentration is such a fascinating study that the whole of this lecture could be most happily devoted to discussion of the stress distribution round all sorts of special boundaries. At the same time the most detailed knowledge of elastic stress distribution is of little value unless we can be sure how the stresses computed will be reflected in the actual strength of the part. For that reason this paper is divided into three sections: the first deals with certain moderately simple cases of stress and load concentration and shows how the stress analysis is confirmed by static and fatigue tests: the second describes some investigations of special two–dimensional boundaries and indicates, some fairly general theoretical conclusions which can be drawn: in the third I shall try to review the possible reasons why, in practice, the best found conclusions are not always borne out.

scholarly journals Investigation of Photoelastic Property and Stress Analysis for Optical Polyimide Membrane through Stress Birefringence Method

Coatings ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 56
Author(s):  
Guohan Gao ◽  
Danbo Mao ◽  
Renkui Jiang ◽  
Zhiwei Li ◽  
Xin Liu ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Stress Distribution ◽  
Stress Analysis ◽  
Principal Stress ◽  
Stress Ratio ◽  
Stress Measurement ◽  
Optical Element ◽  
Membrane Materials ◽  
Polyimide Membrane

Optical polyimide (PI) membranes have been increasingly attractive in optoelectronic substrate and optical element material applications. Controlled stress distribution is very important to optical PI membrane-based optics. However, nondestructive absolute stress measurement inside optical PI membranes remains challenging. In this letter, we adopted the stress birefringence method to experimentally investigate the correlation between stress and retardation in uniaxially, biaxially, and circularly stretched PI membranes. The calculated value of the photoelastic coefficient was found to be around 400 nm/Mpa·cm. A theoretical model was established where the retardation angle is the negative arctan of the principal stress ratio in the biaxially stretched membrane. We also found that the average retardation angle is an important parameter for evaluating the uniformity of stretching force in the circularly stretched membrane. This work provides a better understanding of the stress birefringence measurement of membrane materials.

The Stress Analysis and Experimental Research of Tubular Joints of Offshore Drilling Platform

1984 ◽  
Vol 106 (1) ◽  
pp. 43-45
Author(s):  
T. Y. Chen ◽  
B. Z. Chen ◽  
Y. Q. Wang
Keyword(s):  
Stress Concentration ◽  
Stress Distribution ◽  
Stress Analysis ◽  
Experimental Research ◽  
Stress Concentration Factor ◽  
Analytical Method ◽  
Concentration Factor ◽  
Offshore Drilling ◽  
Tubular Joints ◽  
Good Agreement

An analytical method for the stress analysis of tubular joints of T, Y, K type is presented in this paper. The stress distribution and stress concentration factor of the joints are calculated. Numerical results are in good agreement with the experimental results.

scholarly journals Stress analysis of infinite laminated composite plate with elliptical cutout under different in plane loadings in hygrothermal environment

2021 ◽  
Vol 8 (1) ◽  
pp. 1-12
Author(s):  
Ashok Magar ◽  
Achchhe Lal
Keyword(s):  
Stress Concentration ◽  
Stress Distribution ◽  
Composite Plate ◽  
Volume Fraction ◽  
Elliptical Hole ◽  
Laminated Composite ◽  
Laminated Composite Plate ◽  
Concentration Changes ◽  
Hygrothermal Environment ◽  
Plate Analysis

Abstract This paper presents the solution of stress distribution around elliptical cutout in an infinite laminated composite plate. Analysis is done for in plane loading under hygrothermal environment. The formulation to obtain stresses around elliptical hole is based on Muskhelishvili’s complex variable method. The effect of fibre angle, type of in plane loading, volume fraction of fibre, change in temperature, fibre materials, stacking sequence and environmental conditions on stress distribution around elliptical hole is presented. The study revealed, these factors have significant effect on stress concentration in hygrothermal environment and stress concentration changes are significant with change in temperature.

Sign in / Sign up

Export Citation Format

Share Document