scholarly journals Investigation of the Damping Capacity of CFRP Raft Frames

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 653
Author(s):  
Jinguang Zhang ◽  
Jun Rao ◽  
Lei Ma ◽  
Xianglong Wen

In this paper, based on the composite laminated plate theory and a strain energy model, the damping capacity of a Carbon Fiber Reinforced Plastics (CFRP) raft frame was studied. According to the finite element analysis (FEA) and damping ratio prediction model, the influences of different layups on the damping capacity of the raft frame and its components (top/bottom plate and I-support) were discussed. Comparing the FEA results with the test results, it can be figured out that the CFRP laminate layup has a great influence on the damping ratio of the raft frame, and the maximum error of the first-order natural frequency and damping ratio of the top/bottom plate were 5.6% and 15.1%, respectively. The maximum error of the first-order natural frequency of the I-support between the FEA result and the test result was 7.5%, suggesting that because of the stress concentration, the error of the damping ratio was relatively large. As for the raft frame, the damping performance was affected by the I-support arrangement and the simulation analysis was in good agreement with the experimental results. This study can provide a useful reference for improving the damping performance of CFRP raft frames.

2018 ◽  
Vol 37 (4) ◽  
pp. 669-681 ◽  
Author(s):  
Mo Yang ◽  
Yefa Hu ◽  
Jinguang Zhang ◽  
Guoping Ding ◽  
Chunsheng Song

In this paper, an analytical model for the flexural vibration damping of Carbon Fiber Reinforced Plastics (CFRP) cantilever beams was proposed, which is based on the Lamination Theory and Euler–Bernoulli Beam Theory. By using a finite element analysis and an analytical model, four sets of specific damping capacity with different pavement schemes were predicted, and flexural vibration test and damping analysis were carried out. Comparing the analytical model, finite element analysis, and test results, it could be found that the analytical model had relatively good accuracy in predicting the first-order natural frequency and specific damping capacity of the bending vibration of CFRP beams. The maximum error of the first-order natural frequency between the analysis result and the experimental result was 7.05%; the maximum specific damping capacity error was only 5.65%. Comparing the finite element analysis method and the experiment results, the maximum error of the first-order natural frequency was 7.8%, the error of the specific damping capacity was bigger, and the [±30°]5S specimen was as high as 18.7%. However, there was a significant error when the analytical model was used to predict the second-order natural frequency and the specific damping capacity of CFRP beam’s flexural vibration.


Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2437 ◽  
Author(s):  
Waheed AbuShanab ◽  
Essam Moustafa

The demand for nondestructive testing has increased, especially in welding testing. In the current study, AA1060 aluminum plates were jointed using the friction stir welding (FSW) process. The fabricated joints were subjected to free vibration impact testing in order to investigate the dynamic properties of the welded joint. Damping capacity and dynamic modulus were used in the new prediction method to detect FSW defects. The data acquired were processed and analyzed using a dynamic pulse analyzer lab shop and ME’Scope’s post-processing software, respectively. A finite element analysis using ANSYS software was conducted on different types of designed defects to predict the natural frequency. The results revealed that defective welded joints significantly affect the specific damping capacity. As the damping ratio increased, so did the indication of opportunities to increase the presence of defects. The finite element simulation model was consistent with experimental work. It was therefore revealed that natural frequency was insufficient to predict smaller defects.


2014 ◽  
Vol 969 ◽  
pp. 97-100 ◽  
Author(s):  
Eva Kormaníková

The paper deals with numerical modeling of delamination of laminate plate consists of unidirectional fiber reinforced layers. The methodology adopts the first-order shear laminate plate theory and fracture and contact mechanics. There are described sublaminate modeling and delamination modeling by the help of finite element analysis. With the interface modeling there is calculated the energy release rate along the lamination front. Numerical results are given for mixed mode delamination problems by implementing the method in a 2D finite analysis, which utilizes shear deformable plate elements and interface elements. Numerical example is done by the commercial ANSYS code.


2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Zhiqiang Huang ◽  
Xun Peng ◽  
Gang Li ◽  
Lei Hao

This paper is focused on the influence of the rough contact interfaces on the dynamics of a coupled mechanical system. For this purpose, a two-degree-of-freedom model of a coupled seismic-vibrator-rough-ground system is proposed with which the nonlinear vibration properties are analyzed. In this model, the force-deflection characteristic of the contact interfaces is determined by finite element analysis. By analyzing the undamped free vibration, it was found that the variation of the second-order natural frequency with amplitude increases with rougher contact interfaces; however, the amplitude has little influence on the first-order natural frequency of the system. For the harmonic excited analysis, the jump frequencies and hysteretic region both decrease with rougher contact interfaces. Moreover, it is inferred from the bifurcation diagrams that, increasing the excitation force, the system can bring about chaotic motions on rough contact interfaces.


2018 ◽  
Vol 173 ◽  
pp. 01032
Author(s):  
WL Zeng ◽  
Q Cong ◽  
Y Liu

In this paper, the two methods for solving finite element problem, theoretical calculation method and ANSYS simulation analysis method, were used to study deformation and stress situation of each node of triangular truss under different distribution loads. The results of theoretical calculation were compared with those of ANSYS simulation, which showed that the counter-acting forces of each node were exactly the same. For the calculation results of the equivalent stiffness constants of each unit could not be accurate, values of each node deformation calculated by theoretical calculation could be error, but the maximum error rate was no more than 3.6%. By the comparison results, conclusion could be made that the results of ANSYS simulation are more intuitive and image, the values are more accurate and reliable, comparing with those of theoretical calculation, the influence of accuracy of equivalent stiffness constant is much more smaller.


2012 ◽  
Vol 503 ◽  
pp. 118-121
Author(s):  
Zhen Lu Wang ◽  
Xue Jin Shen ◽  
Ling Zhou ◽  
Xiao Yang Chen

This paper is focused on the finite element analysis (FEA) and theoretical calculation of vibration characterization of V-shaped electrothermal microactuator. A vibration mechanical model about V-shaped electrothermal microactuator is presented. By having a comparison between FEA and theoretical calculation about natural frequencies of V-shaped electrothermal microactuator, the maximum error is within 0.19 %. This paper also analyzes the influences of microactuator geometric parameters on natural frequency. The length and thickness have larger effect on the natural frequency of the actuator, while the angle and width have less effect on the natural frequency.


2011 ◽  
Vol 320 ◽  
pp. 269-274
Author(s):  
Yin Zhu She ◽  
Ming Lv ◽  
Shi Ying Wang

Ultrasonic gear honing is a kind of precision processing technology with great application prospect. The gear is a special kind of load in ultrasonic machining, and its vibration characteristic and natural frequency has great influence on processing frequency of the system. According to the structure characteristic of the gear with stepped variable thickness, its equations of axisymmetric bending vibration frequency were derived on the basis of the thick plate theory in this paper, and then the gear’s natural frequency is obtained which is in accordance with the results of FEM computation. Besides, the main factors affecting the calculation accuracy are analyzed with some examples in this paper The analysis shows that within the application range of Mindlin’s plate theory, the gears’ frequency obtained by the suggested method is accurate.


2019 ◽  
Vol 33 (14n15) ◽  
pp. 1940029
Author(s):  
Tae-Yeob Kim ◽  
Sung-Won Yoon ◽  
Je-Hyoung Cho ◽  
Yun-Hae Kim ◽  
Myung-Hyun Kim

In this study, the CFRP shafts made up of T700-SC multilayered composites have been designed to replace the steel shaft of a ship. An important design variable to be considered when designing composite material intermediate shafts is the natural frequency for resonance avoidance at critical rotational speed and torsional strength for axial load. In order to satisfy these, strength and modal analysis were performed. In order to minimize the deformation of the shape due to the residual stress after mandrel removal, it was laminated by axial symmetry. The fibers orientation angle has a great influence on the natural frequency of the drive shaft. The carbon fiber should be closely oriented at [Formula: see text] to improve the modulus of elasticity in the direction of length of the intermediate shaft and to increase the natural frequency. Also, the optimum fiber orientation for maximum torsional strength should be close to [Formula: see text]. The stacking pattern and the stacking order were finally decided considering the results of the finite element analysis (FEA).


2013 ◽  
Vol 788 ◽  
pp. 508-510
Author(s):  
Xing Hua Cheng ◽  
Fu Ma

This article research frame supported shear wall structure Beam-type Transfer layer at the supporting wall (across full) shape and the supporting column two structure forms, in the same form of vertical uniformly distributed load, the stress distribution variation trend and characteristics of the analyzed and discussed. Using large-scale finite element analysis software ANSYS to two different Beam-type Transfer structure of the nonlinear simulation analysis, combined with the stress nephogram of X to the analysis of two kinds of structure forms of the transfer beam and upper wall and the frame work characteristics [. The results of the study show that: In terms of the vertical stress, wall shape across the full shear wall in the stress of the beam structure performance is better, Column will produce large stress in the beam. Shear wall and stress of the transfer beam work together to transform beam has a great influence.


2013 ◽  
Vol 310 ◽  
pp. 244-248
Author(s):  
Rui Li ◽  
Li Xin Guo

Increasing consumption of the automobile make vehicle seat comfort characteristic paid more attention to. Damping performance as the third important factors is not allowed to ignore. A three freedom "human - seat" system model has been created for simulation. The result show that as the natural frequency f0 improved, the two resonance peak frequency of the system also improved, the growth of the first order resonance frequency is quite obvious, the second is less growth. And the higher the f0 the less change is. With the improvement of f0, the first order resonance peak to peak value obviously reduced, and the second order resonance peak to peak value increased. So, it is said that the higher the f0 the poor damping effect in high frequency area. The influence of ξ for the damping ratio of work frequency is not big, but the influence for the amplitude value is significant. Increase the natural frequency can make phase angle decreased when resonance, but the change of damping ratio, do not have obviously changes.


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