高溫量測 建議使用電荷型加速規
台灣思百吉股份有限公司
台北市民生東路三段128號13樓之1 Tel : (02)25462988 Fax: (02)25462989
一般而言，為了量測方便與設置成本之考量，電壓 (IEPE電流驅動) 型加速規，往往成為振動量測的選擇。
但當測試物的溫度高達攝氏100度以上，使用這種內建電路的加速規，就有面對溫度過高，造成探頭損壞的疑慮。
這時候，電荷型加速規會是良好的選擇。
電荷型加速規 是加速規設計製造的原型，一方面能有最大的頻率範圍與動態範圍之輸出，同時提供最大可能的使用壽命與高溫度、高衝擊的耐受能力。
Brüel & Kjær 提供多樣應用之電荷加速規，單軸至三軸，從<1g的微型結構量測至大於150g的微振地板量測。
台北市民生東路三段128號13樓之1 Tel : (02)25462988 Fax: (02)25462989
高雄辦公室：高雄市文自路717號4樓 Tel : (07)3417970 Fax: (07)3417972
網址 : www.bksv.com
環境管理專案部 分機312沈道剛, 分機311吳立偉, 分機166陳又生 : 噪音振動檢驗室 分機315蔡秀玲
These criteria are met for both mounting variants. The rigid body modes occur in both variants at around 30 Hz, but in the upright mounting variant, some resonances are less distinct and between 600 Hz and 1000 Hz additional peaks are present. The upright mounting method’s advantage of a quicker setup is offset by the disadvantage of overestimating the modal damping values and additional resonances. As well as the mounting method, the stinger used to join the structure and shaker also has a major influence on the experiment result (Fig. 4). The blue curve relates to a stinger variant with two clamp sets and the green curve relates to a variant with a simple stud screw clamp fixture. The results are similar in principle, though the simpler variants exhibit additional resonances in the low frequency range and much less distinct resonances in the high frequency range. Consequently, the short, thin, rigid-fixed stinger is better suited to the structure under investigation and to measurements in the frequency range above 1200 Hz.
Modal analysis is conducted by the Block-Lanczos method available in MD Nastran. To correlate the two models (Fig. 5), the experimental data is imported into MATLAB using the UFF format while the numerical data is imported by use of the MATLAB/Nastran interface IMAT FEA. The two datasets are then automatically positioned and correlated. For the first 16 eigenfrequencies, this results in a mean MAC correlation (Fig. 6) of 91% and a mean frequency variation of 1.28%. The MAC correlation is better in the low modes, while the frequency correlation is better in the higher modes.
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