• Title/Summary/Keyword: Ultrasonic nondestructive testing

Search Result 552, Processing Time 0.027 seconds

Evaluation of Internal Defect of Composite Laminates Using A Novel Hybrid Laser Generation/Air-Coupled Detection Ultrasonic System (레이저 발생 초음파와 공기 정합 수신 탐촉자를 이용한 복합재료 적층판의 내부 박리 결함 평가)

  • Lee, Joon-Hyun;Lee, Seung-Joon;Byun, Joon-Hyung
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.28 no.1
    • /
    • pp.46-53
    • /
    • 2008
  • Ultrasonic C-scan technique is one of very popular techniques being used for detection of flaws in polymer matrix composite(PMC). However, the application of this technique is very limited for evaluation of defects in PMC fabricated by the automated fiber placement process. The purpose of this study is to develop a novel ultrasonic hybrid system based on nondestructive and non-contact ultrasonic techniques for evaluation of delamination in carbon/epoxy and carbon/PPS composite laminates. It was shown that the newly developed ultrasonic hybrid system based on dual air-coupled pitch-catch technique with ultrasonic scattering reflection concept could provide excellent image with higher resolution of delamination in PMC compared with the conventional pitch-catch method. It is expected that this ultrasonic hybrid technique can be applied for on-line inspection of flaws in PMC during the fabrication process.

Nondestructive Evaluation by Joint Time-Frequency Analysis of Degraded SUS 316 Steel (열화된 SUS 316강의 시간-주파수 해석에 의한 비파괴평가)

  • Lee, Kun-Chan;Oh, Jeong-Hwan;Nam, Ki-Woo;Lee, Joo-Suk
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.19 no.4
    • /
    • pp.270-276
    • /
    • 1999
  • Fourier transform has been one of the most commonly used tools in study of frequency characteristics of signal. However, based on the Fourier transform. it is hard to tell whether a signal's frequency contents evolve in time or not. Recently, to overcome Fourier transform fault. not to represent non-stationary signal, time-frequency analysis methods are developed and those can represent informations of signal's time and frequency at the same time. In this study we analysed ultrasonic signal for degraded SUS 316 with time-frequency analysis method. In particular the methods such as short time Fourier(STFT) and Wigner-Ville distribution(WVD) were used to extract frequency contents and characteristics from ultrasonic signals.

  • PDF

Evaluation of Elastic Properties and Analysis of Contact Resonance Frequency of Cantilever for Ultrasonic AFM (초음파원자현미경 캔틸레버의 동특성 해석과 탄성특성 평가)

  • Park, Tae-Sung;Kwak, Dong-Ryul;Park, Ik-Keun;Kim, Chung-Seok;Jhang, Kyung-Young
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.31 no.2
    • /
    • pp.174-180
    • /
    • 2011
  • Nondestructive surface imaging of elastic characteristic and mechanical property has been studied on nanoscale surface with ultrasonic AFM. Resonance frequency variation of cantilever is theoretically analyzed with respect to contact mechanics as well as experimentally measured. The contact resonance frequency is calculated theoretically using the spring-mass and Herzian model in accordance with the resonance frequency of UAFM cantilever measured experimentally. Consequently, the topography and amplitude images could be obtained successfully and the elastic characteristic at the nanoscale surface was evaluated qualitatively by amplitude signals.

Using Field Programmable Gate Array Hardware for the Performance Improvement of Ultrasonic Wave Propagation Imaging System

  • Shan, Jaffry Syed;Abbas, Syed Haider;Kang, Donghoon;Lee, Jungryul
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.35 no.6
    • /
    • pp.389-397
    • /
    • 2015
  • Recently, wave propagation imaging based on laser scanning-generated elastic waves has been intensively used for nondestructive inspection. However, the proficiency of the conventional software based system reduces when the scan area is large since the processing time increases significantly due to unavoidable processor multitasking, where computing resources are shared with multiple processes. Hence, the field programmable gate array (FPGA) was introduced for a wave propagation imaging method in order to obtain extreme processing time reduction. An FPGA board was used for the design, implementing post-processing ultrasonic wave propagation imaging (UWPI). The results were compared with the conventional system and considerable improvement was observed, with at least 78% (scanning of $100{\times}100mm^2$ with 0.5 mm interval) to 87.5% (scanning of $200{\times}200mm^2$ with 0.5 mm interval) less processing time, strengthening the claim for the research. This new concept to implement FPGA technology into the UPI system will act as a break-through technology for full-scale automatic inspection.

Degradation Assessment of Thermoplastic Synthetic Resin Using Propagation Characteristics of Ultrasound (초음파 전파특성을 이용한 열가소성 합성수지의 열화 평가)

  • Jeon, Woo-Sang;Kim, Gi-Jin;Kwon, Sung-Duk
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.34 no.2
    • /
    • pp.141-147
    • /
    • 2014
  • A nondestructive ultrasonic technique was applied to evaluate the thermal characteristics and degradation of synthetic polymer resin (plastics) with better cost-effectiveness and functionality than glass and metal. Thermoplastic and transparent acrylic resin (PMMA) specimens were annealed at below the glass transition temperature ($T_g$), and the propagation characteristics (attenuation and velocity) were measured. The attenuation increased and the velocity decreased with thermal degradation. The results showed that the thermal aging of the specimens could be evaluated quantitatively and that the Tg could be evaluated qualitatively.

Determination of Incident Angle and Position of Optimal Mode Ultrasonic Beam for Flaw Detection in Anisotropic and Inhomogeneous Weldments by Ray Tracing

  • Zhao, Xinyu;Song, Sung-Jin;Kim, Hak-Joon;Gang, Tie;Kang, Suk-Chull;Choi, Yong-Hwan;Kim, Kyung-Cho;Kang, Sung-Sik
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.27 no.3
    • /
    • pp.231-238
    • /
    • 2007
  • Ultrasonic inspection of austenitic steel weldments is a truly difficult task due to complicated wave propagation phenomena such as beam skewing, splitting and distortion. In order to understand these phenomena and design proper inspection procedures, simulation is increasingly paid more attention to. This article addresses a ray tracing based approach to determine incident angle and position of optimal wave mode ultrasonic beam for flaw detection in anisotropic and inhomogeneous austenitic steel weldments. Specially, the optimal mode of ultrasonic wave wave is selected by ray tracing simulation, and an optimization approach based on ray tracing and bi-section search is proposed in order to find the ray path connecting two given points in weldments. With help of this approach, the optimal incident angle and position of ultrasonic beam can be determined for a given flaw position.

Nondestructive evaluation of spot weld quality using by ultrasonic measurement (초음파계측에 의한 SPOT용접품질의 비파괴평가)

  • 박익근
    • Journal of Welding and Joining
    • /
    • v.12 no.3
    • /
    • pp.109-117
    • /
    • 1994
  • Spot welding has wide used with a high work efficiency in the automotive and aerospace industries. Up to the present, the technique mainly used to test spot welds on production lines has been entirely depended upon destructive chisel or peel testing. Therefore, it's being very important assignment to secure the NDE technique which can be evaluate spot weld quality with more efficiency and high reliability. This paper discusses the feasibility of UNDE techniques to evaluate spot weld quality. For the sake of the approach to the quantitative measurement of nugget diameter and the discrimination of a the corona bond from nugget, ultrasonic c-scan image and distribution of reflective echo amplitude was measured by immersion method with the mechanical and the electronic scanning of point-focussed ultrasonic beam(25 MHz). As the results of this study, corona bond which is the most dangerous types of interface defects can be successfully detected, as well as expulsion and voids. Ultrasonic testing results were confirmed and compared by optical microscope and SAM(Scanning Acoustic Microscope) observation of the spot-weld cross section. The results show that the nugget diameter can be successfully measured with the accuracy of 0.8 mm.

  • PDF

Modeling of Radiation Beams from Ultrasonic Transducers in a Single Medium (단일 매체에서의 평면 초음파 탐촉자의 방사 음장 모델링 기법)

  • Song, Sung-Jin;Kim, Hak-Joon
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.20 no.2
    • /
    • pp.91-101
    • /
    • 2000
  • Modeling of radiation beam from ultrasonic transducers has been investigated extensively, since it is one of the most important, fundamental issues that have great influence on the accuracy of an ultrasonic measurement model. Here, three popular radiation models, namely the Rayleigh-Sommerfeld integral model, the boundary diffraction wave model and the edge element model, are discussed briefly, and the radiation beam fields from ultrasonic transducers with planar, circular and rectangular cross-sections are calculated using these three models. Then, the accuracy and the time-efficiency of these methods are compared based on the calculation results.

  • PDF

Development of a Multi-Channel Ultrasonic Testing System for Automated Ultrasonic Pipe Inspection of Nuclear Power Plant (원전 배관 자동 초음파 검사를 위한 다채널 초음파 시스템 개발)

  • Lee, Hee-Jong;Cho, Chan-Hee;Cho, Hyun-Joon
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.29 no.2
    • /
    • pp.145-152
    • /
    • 2009
  • Currently almost all in-service-inspection techniques, applied in domestic nuclear power plants, are partial to field inspection technique. These kinds of techniques are related to managing nuclear power plants by the operation of foreign-produced inspection devices. There have been so many needsfor development of native in-service-inspection device because there is no native diagnosis device for nuclear power plant inspection yet in Korea. In this research, we developed several core techniques to make an automated ultrasonic pipe inspection system for nuclear power plants. A high performance multi-channel ultrasonic pulser/receiver module, an A/D converter module and a digital main CPU module were developed and the performance of the developed modules was verified. The S/N ratio, noise level and signal acquisition performance of the developed modules showed proper level as we designed in the beginning.