اثر نویز بر شناسایی سازه‌ای تیرها به روش خروجی-تنها

نوع مقاله : علمی - پژوهشی

نویسندگان

1 مهندسی سازه، دانشکده مهندسی عمران، دانشگاه صنعتی نوشیروانی بابل، بابل، ایران

2 گروه سازه، دانشکده مهندسی عمران، دانشگاه صنعتی نوشیروانی بابل، بابل، ایران

3 دانشیار، دانشگاه صنعتی نوشیروانی بابل

4 گروه مهندسی عمران، دانشگاه پیام نور، تهران، ایران

چکیده

شناسایی سازه‌ای از روش‌های خروجی-تنها با استفاده از داده‌های خروجی سازه انجام می‌شود. این داده‌ها معمولا شامل پاسخ سازه به همراه مقداری نویز است. موفقیت روش‌های خروجی-تنها در تعیین پارامترهای ارتعاشی یک سازه، به نسبت سیگنال به نویز داده‌های خروجی وابسته است. در این مقاله پارامترهای ارتعاشی (فرکانس‌های طبیعی و شکل‌های مودی) یک تیر یک سر گیردار با استفاده از داده‌های خروجی‌ای که نسبت‌های سیگنال به نویز مختلفی دارند، بدست آمده است. پارامترهای ارتعاشی این تیر با استفاده از روش آنالیز مودال تعیین شده و به عنوان مشخصات ارتعاشی مبنای آن تیر در نظر گرفته شد. ورودی مناسبی به این تیر اعمال شده و سیگنال شتاب نقاط مختلف آن بدست آمد. برای ایجاد داده‌های نویزی، نویزهایی با توان‌های مختلف نسبت به توان سیگنال‌ها تولید شده و به آنها اضافه گردید. پارامترهای ارتعاشی این تیر به کمک دو روش خروجی-تنهای جستار قله و شناسایی زیرفضای تصادفی شناسایی شدند. پارامترهای ارتعاشی شناسایی شده با استفاده از این داده‌های آلوده به نویز با نسبت‌های سیگنال به نویز بزرگتر یا مساوی 25، مطابقت خوبی با مشخصات ارتعاشی مبنای تیر یک سر گیردار دارند. در محدوده نسبت سیگنال به نویز 0.25 تا 25 پارامترهای ارتعاشی مربوط به مود اول این تیر قابل شناسایی نبودند، ولی پارامترهای ارتعاشی مربوط به مودهای بالاتر شناسایی شدند.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Effect of noise on output-only structural identification of beams

نویسندگان [English]

  • Seyed Rasoul Nabavian 1
  • Mohammad Reza Davoodi 2
  • Bahram Navayi Neya 3
  • Seyed amin Mostafavian 4
1 Structural Engineering, Faculty of Civil Engineering, Babol Noshirvani University of Technology, Babol, Iran
2 Faculty of Civil Engineering, Babol Noshirvani University of Technology, Babol, Iran
3 Associate professor, Civil Engineering Department, Babol Noshirvani University of Technology
4 Department of Civil Engineering, Payame Noor University (PNU), Tehran, Iran
چکیده [English]

Output-only structural identification is conducted by output data of the structure. These data usually include structural response together with some noise. Success of output-only methods in determining the vibration parameters of a structure depends on the signal to noise ratio (SNR) of the output data. In this paper, the vibration parameters (Natural frequency and Mode shape) of a contilever beam have been obtained using output data which have different signal to noise ratios. The vibration parameters of the beam were determined using modal analysis of finite element model and considered as reference parameters. Then, appropriate input was applied to the beam and the acceleration signal was obtained. To generate noisy data, noise with different powers compared to signal powers were added to acceleration signal. The modal parameters of the beam were obtained using two output-only methods, Peak Picking (PP) and Stochastic Subspace Identification (SSI). The vibration parameters having signal-to-noise ratios greater than 25 (lower noise level) for all considered modes were identified properly. At a signal-to-noise ratio of 0.25 to 25 (higher noise level), it was not possible to identify the modal parameters of the first mode of the beam, but the parameters of the higher modes were identified with good accuracy.

کلیدواژه‌ها [English]

  • Structural identification
  • Output-only method
  • Contilever beam
  • Signal to noise ratio Peak picking
  • Stochastic subspace identification

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سابقه مقاله

  • تاریخ دریافت: 20 اردیبهشت 1397
  • تاریخ بازنگری: 01 مرداد 1397
  • تاریخ پذیرش: 10 مهر 1397

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