This paper presents the investigation of discrete, out-of-plane waviness in thick composite plates with applications to wind turbine blades. The investigation was carried out with the help of air coupled ultrasonics and a two-step procedure was framed to assist production line implementation. The first step involved detection of marcels, and the second step involved the characterization of these marcels with the help of an index called aspect ratio. A set of standardized samples with known aspect ratios were fabricated and used for this study. Finite element models were created to understand the wave propagation in wavy composite plates. All the experimental data was correlated with numerical B-Scans and conclusions concerning the method were made. (2013) The influence of geometry on the flow rate sensitivity to applied voltage within cone-jet mode electrospray J. Appl. Phys. 112, 114510 (2012) Additional information on AIP Conf. Proc. ABSTRACT. This paper presents the investigation of discrete, out-of-plane waviness in thick composite plates with applications to wind turbine blades. The investigation was carried out with the help of air coupled ultrasonics and a two-step procedure was framed to assist production line implementation. The first step involved detection of marcels, and the second step involved the characterization of these marcels with the help of an index called aspect ratio. A set of standardized samples with known aspect ratios were fabricated and used for this study. Finite element models were created to understand the wave propagation in wavy composite plates. All the experimental data was correlated with numerical B-Scans and conclusions concerning the method were made.

This paper discusses the use of pulse echo based ultrasonic testing for the inspection of adhesive bonds between very thick composite plates (thickness greater than 30 mm). Large wind turbine blades use very thick composite plates for its main structural members, and the inspection of adhesive bond-line is very vital. A wide gamut of samples was created by changing the thickness of plate and the adhesive. The influence of experimental parameters such as frequency on measurement is studied in this paper. Two different frequencies are chosen, and the measurement error bars are determined experimentally. T-Ray measurements were used to verify and correct results, and conclusions are made based on the combined results. ABSTRACT. This paper discusses the use of pulse echo based ultrasonic testing for the inspection of adhesive bonds between very thick composite plates (thickness greater than 30 mm). Large wind turbine blades use very thick composite plates for its main structural members, and the inspection of adhesive bond-line is very vital. A wide gamut of samples was created by changing the thickness of plate and the adhesive. The influence of experimental parameters such as frequency on measurement is studied in this paper. Two different frequencies are chosen, and the measurement error bars are determined experimentally. T-Ray measurements were used to verify and correct results, and conclusions are made based on the combined results.