Strength Analysis of Damaged Composite Laminates Repaired by Scarf Bonding Method Based on Three Dimensional Model

2010 ◽  
Vol 44-47 ◽  
pp. 2219-2223
Author(s):  
Feng Liu

The three dimensional finite element model of composite laminates made of carbon fiber reinforced bismaleimide resin is built, and the stress state of the composite laminates under unidirectional tensile force is presented based on finite element analysis. The strength criterion and initial damage mode are given based on the stresses of material principal direction. The three dimensional finite element model of the same laminates with non-penetrating damage repaired by scarf bonding method is built, and the stress state is also analyzed. Annular solids are used to simulate the resin between the mother laminates and the patches. The strength criterion and the damage mode of the scarf bonding composite laminates are also given. The strength and the damage mode of original laminates are compared with that of the repaired laminates. The influence of the annular shape resin is considered in the repaired model. It is showed that the three dimensional models can simulate the geometric and physical features of the real composite laminates. It is concluded that the original composite laminates and the repaired one both damage first in the laminar whose second material principal direction coincides with the axial tensile force. And the damage mode is resin crack under tensile stress. The strength of the bonding patches is higher than the repaired laminates. After scarf bonding repairing, the strength of the damaged laminates can recover up to about 88%.

2010 ◽  
Vol 160-162 ◽  
pp. 81-86
Author(s):  
Feng Liu

The three dimensional finite element model of composite laminates made of carbon fiber reinforced bismaleimide resin is built, and the stress state of the composite laminates under unidirectional tensile force is analyzed. The strength criterion and damage mode are given based on the stresses of material principal direction. The three dimensional finite element models of the same laminates with non-penetrating damage repaired by two kinds of bonding methods are built. The strength criterion and the damage mode of the two kinds of repaired models are also given. The influence of the interlaminar stress is considered in these analysis models. It is showed that the three dimensional models can simulate the geometric and physical features of the real composite laminates. It is concluded that the original composite laminates and the repaired ones both damage first in the laminar whose second material principal direction coincides with the axial tensile force. The damage mode is resin crack under tensile stress. The strength of the bonding patches is higher than the mother laminates. After scarf bonding repair, the strength of the damaged laminates recovers up to about eighty-four percent. With additional surface patch, the strength of the damaged laminates recovers up to about eighty-nine percent. Surface patch can improve the strength of damaged laminates.


2010 ◽  
Vol 26-28 ◽  
pp. 370-375
Author(s):  
Feng Liu ◽  
Wen Feng Qin ◽  
Guo Chun Liu

The three dimensional finite element model of composite laminates made of carbon fiber reinforced bismaleimide resin is built, and the stress state of the composite laminates under unidirectional tensile force is analyzed. The strength criterion and damage mode are given based on the stresses of material principal direction. The three dimensional finite element model of the same laminates with non-penetrating damage repaired by scarf bonding method is built, and the stress state is also analyzed. The strength criterion and the damage mode of the scarf bonding composite laminates are also given. The strength and the damage mode of original laminates are compared with that of the laminates with non-penetrating damage. The influence of the interlaminar stress is considered in these analysis models. It is showed that the three dimensional models can simulate the geometric and physical features of the real composite laminates. It is concluded that the original composite laminates made of carbon fiber reinforced bismaleimide resin and the repaired one both damage first in the laminar whose second material principal direction coincides with the axial tensile force. And the damage mode is resin crack under tensile stress. The strength of the bonding patches is higher than the laminates repaired by scarf bonding. After scarf bonding repair, the strength of the damaged laminates can recover up to about eighty-four percent.


2010 ◽  
Vol 160-162 ◽  
pp. 87-90
Author(s):  
Feng Liu ◽  
Zhong Bo Zhang ◽  
Jun Yan

The three dimensional finite element model of composite laminates made of carbon fiber reinforced bismaleimide resin is built, and the natural vibration of the square composite laminates with clamped edges is analyzed. The natural vibration frequencies and modes of laminates without damage are given based on finite element method. The three dimensional finite element models of the same square laminates with non-penetrating damage repaired by two kinds of bonding methods are built. The natural vibration frequencies and modes are also given. It is showed that the three dimensional models can simulate the geometric and physical features of the real composite laminates. It is concluded that the natural vibration frequencies of the composite laminates all increase after it is repaired either by scarf bonding method or scarf and surface bonding method. After scarf bonding repairing, the lowest natural frequency increases about 3.6% and the second natural frequency increases 3.7%. After scarf and surface bonding repairing, the lowest natural frequency increases about 4.5% and the second frequency increases about 6.4%. The natural vibration modes of different repairing models are similar. The increase of natural frequencies may cause temporary vibration of aircraft skin made of composite laminates. The risk of resonance caused by bonding repairing is small.


2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.


2013 ◽  
Vol 336-338 ◽  
pp. 760-763
Author(s):  
Hui Yue

A short explanation of the finite element method as a powerful tool for mathematical modeling is provided, and an application using constitutive modeling of the behavior of ligaments is introduced. Few possible explanations of the role of water in ligament function are extracted from two dimensional finite element models of a classical ligament. The modeling is extended to a three dimensional finite element model for the human anterior cruciate ligament. Simulation of ligament force in pitching motion of basketball player is studied in this paper.


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