Papers by Author: Pou Man Lam

Abstract: A new biocomposite based on chicken feather fiber (CFF) and Poly (lactic acid) (PLA) was fabricated for the first time by melting compound methods. Its mechanical properties and fracture surfaces were investigated by using tensile tests and scanning electron microscopy (SEM), respectively. The results showed that the tensile modulus and elongation at break of PLA samples were improved by adding a small amount of CFF. The elongation at break of a CFF/PLA sample with 2 wt% of CFF was 56% higher than that of pure PLA. This may ascribe to the good adhesion and interactions between the CFF and PLA matrix.

Abstract: In this paper, fiber Bragg grating (FBG) sensor and piezoelectric (PZT) actuator are used to develop a hybrid system for the evaluation of delamination in glass fiber-reinforced epoxy (GF/EP) composite laminates. The surface-bonded PZT actuator generates ultrasonic Lamb wave in the composite laminates, while the FBG sensor, which is embedded in the composite laminates, captures the Lamb wave signal. Wavelet analysis is introduced to extract signal spectrographic characteristics in the time-scale domain appropriately. Since the propagation characteristics of Lamb wave is altered by the existence of damage in the composite laminates, delamination information can be obtained from the received signal. With the assistance of a signal generation and an acquisition system, this methodology enables active sensing and non-destructive evaluation of delamination in the composite laminates. Experiments have been carried out with GF/EP composite beams to examine the feasibility of the proposed detection technique. The acquired and processed Lamb wave signals corresponding to different delamination sizes are compared.