振動四實(shí)驗(yàn)報(bào)告

實(shí)驗(yàn)四：隔振減振實(shí)驗(yàn)一、實(shí)驗(yàn)?zāi)康?、學(xué)習(xí)隔振減振的基本知識；2、學(xué)些隔振減振的基本原理；3、了解隔振減振效果的測量；4、判斷系統(tǒng)隔振減振的有效工作頻段；二、實(shí)驗(yàn)儀器1、ZJY-601T型振動教學(xué)實(shí)驗(yàn)臺、偏心電機(jī)、激振器。2、空氣阻尼器（圖1）、動力減振器（圖2）。圖1空氣阻尼器圖2動力減振器三、實(shí)驗(yàn)要求利用實(shí)驗(yàn)室提供的減振隔振設(shè)備，設(shè)計(jì)一到兩種隔振或減振方案（從被動隔振、主動隔振、單式動力減振和復(fù)式動力減振中任選），測量所選擇方案的隔振效果以及有效的工作頻段。必須提供安裝示意圖，實(shí)驗(yàn)原理，詳細(xì)的實(shí)驗(yàn)步驟以及數(shù)據(jù)記錄和分析結(jié)果。四、實(shí)驗(yàn)儀器安裝示意圖五、實(shí)驗(yàn)原理隔振的作用有兩個(gè)方面：一是減少振源振動傳至周圍環(huán)境；二是減少環(huán)境振動對物體或設(shè)備的影響。原理是在設(shè)備和底座之間安裝適當(dāng)?shù)母粽衿?，組成隔振系統(tǒng)，以減少或隔離振動的傳遞。有兩類隔振，一是隔離機(jī)械設(shè)備通過支座傳至地基的振動，以減少動力的傳遞，稱為主動隔振；另一種是防止地基的振動通過支座傳至需保護(hù)的精密設(shè)備或儀表儀器，以減小運(yùn)動的傳遞，稱為被動隔振。在一般隔振設(shè)計(jì)中，常常用振動傳遞比和隔振率來評價(jià)隔振效果。主動隔振傳遞比等于物體傳遞到底座的振動與物體振動之比，被動隔振傳遞比等于底座傳遞到物體的振動與底座的振動之比，兩個(gè)方向的傳遞比相等。隔振效率：η=（1-T)·100%傳遞比T：式中D為阻尼比，為激振頻率和共振頻率的比。只有傳遞比小于1才有隔振效果。因此T<1的區(qū)域稱為隔振區(qū)。六、實(shí)驗(yàn)步驟1、把5kg空氣阻尼器組成的隔振器放在底座上，偏心激振電機(jī)安裝在隔振器上，偏心電機(jī)的電壓有調(diào)壓器輸出端提供。220v電源線接到調(diào)壓器的輸入端，一定要小心防止接錯(cuò)，要注意調(diào)壓器的輸入和輸出端，防止接反。2、在隔振器下托板上安裝一加速度傳感器，在上托板上安裝以加速度傳感器，分別接入ZJY-601A型振動教學(xué)試驗(yàn)儀的第一和第二通道，輸出的信號接到采集儀的第一和第二通道。3、開機(jī)進(jìn)入DASP2000標(biāo)準(zhǔn)版軟件的主界面，選擇單通道按鈕。進(jìn)入單通道示波狀態(tài)進(jìn)行波形和頻譜同時(shí)示波。4、在采集參數(shù)菜單中設(shè)置采樣頻率為500HZ,程控1倍、采樣點(diǎn)數(shù)2K、工程單位μm。5、調(diào)節(jié)調(diào)壓器改變電機(jī)轉(zhuǎn)速，使系統(tǒng)產(chǎn)生共振，打開數(shù)據(jù)列表按鈕從頻率計(jì)中讀取頻率值f0、振幅以及第一通道的峰值A(chǔ)1和第二通道的峰值A(chǔ)2。七、數(shù)據(jù)處理與分析：校正波形如下：表1頻譜峰值列表==============================================================================================序號CH1頻率CH1幅值CH1阻尼比(%)CH2頻率CH2幅值CH2阻尼比(%)----------------------------------------------------------------------------------------------0139.39459.939890.00039.39249.833190.0000242.53521.4488-200.00042.55231.43137-200.0000347.39490.571837-200.00047.41710.557447-200.0000432.69130.514897-300.00032.69960.551394-300.0000549.32480.469637-200.00050.26590.469766-200.0000628.83570.3914912.45828.82270.4223082.1740726.79740.261447-200.00053.23230.357505-200.0000823.95570.250775-300.00023.99160.2815784.2510961.99310.238999-200.00057.130.311494-200.0001063.97310.228207-200.00025.96220.260694-200.000空氣阻尼器加砝碼的固有頻率測量如圖：表1頻譜峰值列表==============================================================================================序號CH1頻率CH1幅值CH1阻尼比(%)CH2頻率CH2幅值CH2阻尼比(%)----------------------------------------------------------------------------------------------0114.21331.384467.22614.05581.482963.3940227.81330.3076727.1155.419941.5616120.5650339.56790.2596841.90118.26261.140290.0000430.77170.224453-200.00011.25041.18002-200.000057.314950.177625-300.0008.340231.12083-200.0000635.59770.162057-300.00024.0190.6836470.0000721.97440.155776-200.00021.96180.675983-300.000084.229760.1170213.92142.63750.4148931.2460936.62230.146588-200.00029.86610.365129-200.0001044.47340.12268-200.00039.50110.3634010.748==============================================================================================固有頻率為f=14Hz.實(shí)驗(yàn)記錄數(shù)據(jù)如下：通道1通道2比值fA1fA2A1/A28.040.418.000.440.9329.010.709.000.820.85410.001.239.991.231.00010.511.6110.501.391.15810.972.0910.981.651.26711.993.8211.982.301.66113.008.4413.003.042.77614.0111.5413.992.434.74914.2011.1114.192.225.00514.3910.5514.402.045.17214.609.9014.581.865.32315.018.8215.001.685.25015.408.0915.381.744.64915.807.4215.801.854.01116.216.8916.191.913.60716.506.5216.511.923.39616.716.3116.711.903.32116.996.1517.001.953.15417.196.0617.192.042.97117.415.8817.392.102.80017.705.6817.722.282.49118.005.6217.992.432.31318.305.5018.292.562.14819.005.3519.013.011.77720.005.3519.993.751.42721.005.5620.994.761.16821.996.1222.006.410.9523.007.2322.999.300.7824.007.0424.0010.300.6825.005.3325.008.050.6625.105.4825.108.390.6525.205.2825.207.890.6725.504.9425.507.340.6726.004.4025.996.350.6926.504.2126.495.770.7327.004.1326.995.490.7529.004.2029.005.600.7530.003.8930.005.160.75曲線圖如下：由曲線知A1與A2出現(xiàn)第一個(gè)峰時(shí)候的頻率大約為14Hz，A1為空氣阻尼器振動幅值，A2為梁系統(tǒng)振動的幅值，此點(diǎn)為反共振點(diǎn)，理論知識如下：當(dāng)激勵頻率等于空氣阻尼器加砝碼后的振動固有頻率時(shí)就會出現(xiàn)反共振點(diǎn)。由A1/A2曲線知，當(dāng)激勵頻率為25Hz時(shí)出現(xiàn)隔振，數(shù)據(jù)與圖如下：序號CH1頻率CH1幅值CH1阻尼比(%)CH2頻率CH2幅值CH2阻尼比(%)----------------------------------------------------------------------------------------------0125.0955.344890.00025.09678.126570.0000250.15830.6021330.57250.171.040640.5900335.53430.3411780.64535.52720.595281.1170414.20460.3732256.760322.1330.3381490.0000518.05510.365184-300.00016.09190.37822-300.0000648.32550.247074-300.00038.60590.364363-200.0000744.49820.2074231.64010.27450.283678-300.0000838.63970.181767-200.000325.6540.260960.139098.312830.180672-200.000175.1570.1952930.000107.316270.1