声学技术
聲學技術
성학기술
Technical Acousitics
2010年
1期
44-47
,共4页
杨书荣%吴伟%邬冠华%王伏喜
楊書榮%吳偉%鄔冠華%王伏喜
양서영%오위%오관화%왕복희
TOFD检测%信号处理%结构噪声%分离谱%定量精度
TOFD檢測%信號處理%結構譟聲%分離譜%定量精度
TOFD검측%신호처리%결구조성%분리보%정량정도
TOFD testing%Signal processing%Structure noise%Sprit-spectrum%Quantitative precision
超声衍射时差(TOFD)方法因具有普通超声检测和射线检测的优点而被广泛应用于中厚板的焊缝检测与缺陷定量中.TOFD技术检测的是相对微弱、指向性差的衍射波信号,被检测材料所产生的结构噪声也会降低检测信号的信噪比,影响了TOFD检测的精度.将分离谱技术用于超声TOFD检测信号的处理,采用线性平均、极值阙值、极值阈值+最小值、最小值等四种恢复算法进行比较,并在最小值算法的基础上引入最小值选中次数加权算法恢复信号.结果表明:与传统的滤波方法相比,该方法能有效地提高了回波信号的信噪比,减小了TOFD检测中的缺陷定量误差.
超聲衍射時差(TOFD)方法因具有普通超聲檢測和射線檢測的優點而被廣汎應用于中厚闆的銲縫檢測與缺陷定量中.TOFD技術檢測的是相對微弱、指嚮性差的衍射波信號,被檢測材料所產生的結構譟聲也會降低檢測信號的信譟比,影響瞭TOFD檢測的精度.將分離譜技術用于超聲TOFD檢測信號的處理,採用線性平均、極值闕值、極值閾值+最小值、最小值等四種恢複算法進行比較,併在最小值算法的基礎上引入最小值選中次數加權算法恢複信號.結果錶明:與傳統的濾波方法相比,該方法能有效地提高瞭迴波信號的信譟比,減小瞭TOFD檢測中的缺陷定量誤差.
초성연사시차(TOFD)방법인구유보통초성검측화사선검측적우점이피엄범응용우중후판적한봉검측여결함정량중.TOFD기술검측적시상대미약、지향성차적연사파신호,피검측재료소산생적결구조성야회강저검측신호적신조비,영향료TOFD검측적정도.장분리보기술용우초성TOFD검측신호적처리,채용선성평균、겁치궐치、겁치역치+최소치、최소치등사충회복산법진행비교,병재최소치산법적기출상인입최소치선중차수가권산법회복신호.결과표명:여전통적려파방법상비,해방법능유효지제고료회파신호적신조비,감소료TOFD검측중적결함정량오차.
With the advantage of precise quantification,ultrasonic time-of-flight-diffraction (TOFD) technique has been widely using in weld detection and defect quantification of middle thick plate.The signals detected by using TOFD technique are relatively weak diffraction wave signals with poor directivity,and the structure noise generated by the detected material will also reduce the signal-to-noise ratio and therefore affect the detection sensitivity of TDFD technique..The split-spectrum technique is used for processing the ultrasonic TOFD detecting signal in this paper.Four restoration algorithms,i.e.the linear average, the maximal threshold,the maximal threshold+minimal value and the minimal value,are adopted for comparison.In the end the weighted algorithm of minimal number selected based on the minimal value algorithm is used to restore the signal.Compared with the traditional filtering method.the results show that this method can effectively increase the signal-to-noise ratio of echo signal and reduce the defect quantitative error of TOFD detection.