Microstructure Effects of Ultrasonic Waves in a Fiber Reinforced Composite Plate

2000 ◽  
Vol 17 (10) ◽  
pp. 740-742
Author(s):  
Han Jun-Bo ◽  
Tang Li-Guo ◽  
Cheng Jian-Chun ◽  
Berthelot Yves
2012 ◽  
Vol 488-489 ◽  
pp. 676-680
Author(s):  
Pramod Kumar ◽  
S.K. Tiwari

Finite element analysis has been used to find out eigen values and mode shape for fiber reinforced composite plates. FRC plates are important structural elements in modern engineering structures. Vibrations of laminated composite plates have been the subject of significant research activities in recent years. Last two decades have witnessed continued development of advanced composite and other high performance aerospace materials with increased specific strength and modulus, longer fatigue life, higher combat survivability etc. Advanced composite laminates extend the possibility of optimal design through the variation of stacking sequence and fiber orientation, known as composite tailoring. The benefits that accrue from this are not attainable without solving the complexities that are introduced by various coupling effects, such as bending–stretching and bending-twisting. Even, as the matrix material is of relatively low shearing stiffness as compared to the fibers, a reliable prediction of frequency response of laminated plates must account for transverse shear deformation. A four noded quadrilateral finite element is considered for the study of frequency response of composite plate. An analytical solution to the boundary value problem of free vibration response of arbitrarily laminated plates subjected to an admissible boundary condition is presented. A rectangular fiber reinforced composite plate is modeled in FEM software (NISA 15) and natural frequencies, mode shapes are obtained and are compared with the available analytical solutions.


2019 ◽  
Vol 9 (11) ◽  
pp. 2334 ◽  
Author(s):  
Qi Zhu ◽  
Yuxuan Ding ◽  
Dawei Tu ◽  
Haiyan Zhang ◽  
Yue Peng

Diffuse wave inspection benefits from multiple scattering and is suitable for the nondestructive testing of complex structures with high sensitivity. This paper aims to localize the defect in a cross-ply carbon fiber reinforced polymer composite with the diffuse wave field experimentally based on the Locadiff technique. Firstly, the wave diffusivity and dissipation parameters are determined from the diffuse waveforms. Great dissipation is found for this composite plate due to its strong viscoelasticity, which makes the amplitude attenuate fast in a short propagation distance. The signal-to-noise ratios degrade significantly at off-axis directions so that only measurements along the X and Y axes are chosen. Secondly, the decorrelation coefficients are determined using the stretching technique. The decorrelation coefficients decrease initially due to the interaction between the wave fields and the defect and subsequently increase due to the low signal-to-noise ratio at the later time. Based on these data, a sensitivity time domain is chosen to center at t = 50 μs. Together with the defect sensitivity kernel calculated under constant diffusion property assumption, the defect is localized at [270 mm, 265 mm] compared to [300 mm, 280 mm] in the final reference state. This method is promising for early damage detection in fiber reinforced composite structures.


Sign in / Sign up

Export Citation Format

Share Document