CAJ | 학술논문

常规近场声全息(Near-field acoustic holography,NAH)中,为减小算法误差对结果的影响,要求全息测量孔径必须大于声源面积.由于要求的全息孔径较大,导致该技术测量工作异常繁琐以及在大尺寸结构上应用困难.为解决此问题,以全息声压近场外推为基础的Patch近场声全息技术(Patch near-field acoustic holography, PNAH)发展起来.根据声场的球面波近似原理,提出正交球面波Patch近场声全息方法,该方法将振动体产生的声场等效近似为一系列不同阶次的正交球面波源产生的声场的线性叠加,通过这些正交球面波源的声辐射过程来实现全息面声压的近场外推,然后利用近场外推所得声压数据采用计算简便的快速傅里叶变换(Fast Fourier transform,FFT)方法实现全息重建.数值仿真结果表明,该方法在小全息孔径条件下取得良好效果,显著减小对全息孔径大小的要求,从而方便工程运用.
상규근장성전식(Near-field acoustic holography,NAH)중,위감소산법오차대결과적영향,요구전식측량공경필수대우성원면적.유우요구적전식공경교대,도치해기술측량공작이상번쇄이급재대척촌결구상응용곤난.위해결차문제,이전식성압근장외추위기출적Patch근장성전식기술(Patch near-field acoustic holography, PNAH)발전기래.근거성장적구면파근사원리,제출정교구면파Patch근장성전식방법,해방법장진동체산생적성장등효근사위일계렬불동계차적정교구면파원산생적성장적선성첩가,통과저사정교구면파원적성복사과정래실현전식면성압적근장외추,연후이용근장외추소득성압수거채용계산간편적쾌속부리협변환(Fast Fourier transform,FFT)방법실현전식중건.수치방진결과표명,해방법재소전식공경조건하취득량호효과,현저감소대전식공경대소적요구,종이방편공정운용.
In order to reduce the reconstructed errors, the near-field acoustic holography requires the measurement aperture larger than the sound source area. This limitation causes heavy measurement work and makes the NAH difficult to implement on large-scale structure. To solve this problem Patch near-field acoustic holography based on hologram pressure extrapolation is developed. A new patch near-field acoustic holography (PNAH) based on exploration using orthogonal spherical wave source is proposed. According to the solution of Helmholtz equation in spherical coordinates, the sound field can be approximately expressed as a linear sum of a series of orthogonal spherical wave function, so that the sound field generated by vibrator is approximated by superposing fields generated by a series of orthogonal spherical wave sources of different orders and the pressure exploration is realized by radiating process of these spherical wave sources. After near-field exploration the fast Fourier transform (FFT) method is implemented for reconstructing the normal velocity or the field on and near the radiator. The results of numerical simulations show that the method can work well in the small measurement aperture, reduce the requirement of measurement aperture area, and is convenient for application.