Cross-axis sensitivity of accelerographs with pendulum like transducers—mathematical model and the inverse problem
✍ Scribed by Todorovska, Maria I.
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 313 KB
- Volume
- 27
- Category
- Article
- ISSN
- 0098-8847
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✦ Synopsis
A mathematical model for a three-component accelerograph is presented that accounts for the e ects of transducer misalignment and cross-axis sensitivity. The former refers to departures in the alignment of the transducer penduli (typically of the order of few degrees) from an ideal orthogonal system, and the latter to a transducer recording components of motion in directions other than its principal sensitivity axis. Transducer misalignment magniÿes the e ects of cross-axis sensitivity. These e ects are signiÿcant only for large amplitude recordings (peak acceleration close to 1g), for example in the near-ÿeld of the 1994 Northridge, California, earthquake. The misalignment angles and the angular ampliÿcation constant can be determined by a static tilt test, performed in the ÿeld, and solving a generalized inverse problem. This paper presents an algorithm for solution of this inverse problem on a routine basis. Practical implementation of the algorithm and results for 76 instruments of the Los Angeles Strong Motion Array are presented in a separate paper. ?