A Three-Dimensional Finite Element Stress Analysis of Plain-Woven CFRP Adhesive Laminated Plates and Hollow Cylinder Under Out-of-Plane Loading

Author(s):  
Toshiyuki Sawa ◽  
Yukiya Noshita ◽  
Takeshi Iwamoto

Carbon-Fiber-Reinforced-Plastic (CFRP) laminates have been used extensively in many industrial applications because of their good mechanical properties, such as high specific strength and elastic modulus. However, when CFRP laminated plate is bent, cracks and delaminations occur at the interfaces where fiber orientations are changed. Therefore, it is important to know the stress distributions at the interfaces. In this study, the stress distributions of plain-woven CFRP adhesive laminated plates and hollow cylinder bonded reinforcements under out-of-plane loads are examined. Stress distributions in the CFRP laminated plates are analyzed using three-dimensional Finite Element Method. The effects of the thickness, stiffness and length of coating reinforcements are examined in the numerical calculations. The three point bending tests were carried out for the verifications of the FEM calculations. The strains at the interfaces, the deflection and the delaminations stress were measured under static out-of-plane loading. A fairly good agreement was seen between the FEM calculations and the experimental results concerning the strains and the deflections. Moreover, the mechanism of delaminations is examined using the interface stress distributions in the CFRP laminated plates.

Author(s):  
Yukiya Noshita ◽  
Toshiyuki Sawa ◽  
Yuya Omiya

Stress distributions in CFRP adhesive laminated plates subjected to static and impact out-of-plane loadings are analyzed using a three-dimensional finite-element method (FEM). For establishing an optimum design method of the laminated plates, the effects of some factors are examined. As the results, it is found that the maximum value of the von Mises equivalent stress σ eqv occurs at the edge of the CFRP’s interfaces. The maximum value of interface shear stress r i at CFRP interface decreases as the reinforced Young’s modulus and the thickness increases. However, the maximum value of σ eqv at the adhesive layer decreases as the reinforced Young’s modulus and the thickness decreases. In addition, the maximum value of r i at the CFRP’s interface of lower reinforced laminates under impact loadings shows opposite characteristics to those under static loadings. For verification of the FEM calculations, experiments were carried out to measure the strains at the interfaces and the laminates plates strengths. Concerning strain and strength prediction based on von Mises equivalent stress, fairly good agreements were found between the numerical and the experimental results. The FEM results of impacted strain are in fairly good consistent with the measured results. Discussion is made on the effects of some factors on interface stress distributions.


Author(s):  
Kazuo Ogawa ◽  
Nobuyoshi Yanagida ◽  
Koichi Saito

Residual stress distribution in an oblique nozzle jointed to a vessel with J-groove welds was analyzed using a three-dimensional finite element method. All welding passes were considered in a 180-degree finite element (FE) model with symmetry. Temperature and stress were modeled for simultaneous bead laying. To determine residual stress distributions at the welds experimentally, a mock-up specimen was manufactured. The analytical results show good agreement with the experimental measurement data, indicating that FE modeling is valid.


1986 ◽  
Vol 108 (2) ◽  
pp. 99-106 ◽  
Author(s):  
E. F. Rybicki ◽  
J. R. Shadley

The accuracy of a destructive, experimental method for the evaluation of through-thickness residual stress distributions is investigated. The application of the method is to a welded pipe that has been subjected to a residual stress improvement process. The residual stress improvement process introduces gradients in the stress distribution. The question of interest is how well the back-computation method used to interpret the experimental data represents the residual stress distribution for this type of stress profile. To address this question, a finite element model was used to provide a reference stress solution for comparison with the back-computation results of the experimental method. Three-dimensional finite element stress analyses were also conducted to simulate the cutting steps of the destructive laboratory procedure. The residual stress distributions obtained by the back-computation procedure were then compared with the reference stress solutions provided by the finite element model. The comparisons show agreement and indicate that good results can be expected from the experimental method when it is applied to a pipe that has been subjected to a residual stress improvement process, provided that the axial gradient of stress is not too large.


1975 ◽  
Vol 97 (3) ◽  
pp. 199-205 ◽  
Author(s):  
D. P. Jones

Two- and three-dimensional finite element models were used to determine elastic stress distributions in plate ligaments for various in-plane, bending, and thermal loadings. Plates containing triangular penetration patterns of 5 and 10 percent ligament efficiency were analyzed as well as the example of a circular plate containing a single centrally placed hole subjected to step change in temperature on one surface. Detailed descriptions of boundary conditions are given with the results presented in terms of stresses important in tubesheet and vessel closure design considerations. Results show that the minimum ligament section of the perforated region need not be the critically stressed cross section as is currently assumed in the ASME Boiler and Pressure Vessel Code. Further, a thermal shock ΔT applied to the surface of a perforated region will result in a maximum peak stress of EαΔT/(1−ν) and may be significantly lower than the thermal skin stress calculated by the ASME Code procedures.


Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2666
Author(s):  
Jae-Hyun Lee ◽  
Ho Yeol Jang ◽  
Su Young Lee

The present study was designed to compare the stress distributions in two restoration types of implants and the surrounding bone. The first restoration type was a conventional cement-retained zirconia crown, and the second was a novel cementless screw-retained zirconia crown with a base abutment. A three-dimensional finite element method was used to model the implants, restorations, and supporting bone. A comparative study of the two implants was performed under two masticatory loads: a vertical load of 100 N and a 30-degree oblique load of 100 N. Under both loading conditions, the maximum von Mises stress and strain values in the implant and supporting bone were higher in the conventional cement-retained restoration model than in the cementless screw-retained model. In terms of stress distribution, the cementless screw-retained zirconia crown with base abutment may be considered a superior restoration option compared to the conventional cement-retained zirconia crown.


2012 ◽  
Vol 529 ◽  
pp. 224-227
Author(s):  
Bin Li ◽  
Hong Wang

This paper investigates a three-dimensional finite element model for the cross-wedge rolling process has been used to characterize the workpiece material stress and deformation behavior. Considering the characteristic of cross wedge rolling, the static implicit FEM program is selected. To simulate all forming stages in the cross wedge rolling process, dynamic adaptive remeshing technology was applied. Examples of numerical simulation for strain, stress distributions and rolling load components have been included. The stress distributions in the cross-section of the forming workpiece are analyzed to interpret fracture or rarefaction at the center of workpiece. The computer codes in finite element method can be used for a large variety of problems by simply changing the input data.


1984 ◽  
Vol 106 (4) ◽  
pp. 480-488 ◽  
Author(s):  
H. Fessler ◽  
C. D. Edwards

Combined strip and rosette gage measurements and results from three-dimensional, finite element calculations are in excellent agreement with frozen stress photoelastic results for an efficient shape of cast-steel node under axial, brace loading. Three different meshes showed that two layers of elements through the thickness are needed.


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