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電磁式振動(dòng)臺(tái)隨機(jī)振動(dòng)試驗(yàn)?zāi)康呐c振動(dòng)失效模式
電磁式振動(dòng)臺(tái)隨機(jī)振動(dòng)試驗(yàn)?zāi)康呐c振動(dòng)失效模式
Electromagnetic shaker random vibration testing and vibration failure mode
產(chǎn)品在運(yùn)輸和實(shí)際使用中所遇到的振動(dòng)，絕大多數(shù)是隨機(jī)振動(dòng)。例如，宇航器在發(fā)射和助推階段的振動(dòng)；火箭發(fā)動(dòng)機(jī)的噪聲和氣動(dòng)噪聲使結(jié)構(gòu)產(chǎn)生的振動(dòng)；飛機(jī)（特別是高速飛機(jī)）的大功率噴氣發(fā)動(dòng)機(jī)的振動(dòng)；飛機(jī)噪聲使飛機(jī)結(jié)構(gòu)產(chǎn)生的振動(dòng)和大氣湍流使機(jī)翼產(chǎn)生的振動(dòng)；飛機(jī)著陸和滑行時(shí)的振動(dòng)；車輛在不平坦的道路上行駛時(shí)產(chǎn)生的振動(dòng)；多變的海浪使船舶產(chǎn)生的振動(dòng)等，都屬于隨機(jī)振動(dòng)。因此，用電磁式振動(dòng)臺(tái)隨機(jī)振動(dòng)試驗(yàn)機(jī)試驗(yàn)才能更真實(shí)反映產(chǎn)品的抗振性能。
Vibration products encountered in transport and in practical use, the vast majority of random vibration. For example, vibration spacecraft during launch and boost phase; vibration noise and rocket engine noise cause; aircraft (especially high-speed aircraft) the vibration of large jet engines; vibration of aircraft noise the aircraft structure vibration and atmospheric turbulence so that the wing produces vibration of aircraft landing and taxiing; the vibration of vehicle; driving on uneven road when changing the ship generated waves; vibration etc., all belong to the random vibration. Therefore, an electromagnetic shaker random vibration test can more truly reflect the anti vibration performance of the product.
與正弦振動(dòng)相比，隨機(jī)振動(dòng)試驗(yàn)機(jī)的頻率域?qū)挘矣幸粋€(gè)連續(xù)的頻譜，它能同時(shí)在所對(duì)頻率上對(duì)產(chǎn)品進(jìn)行激勵(lì)，各種頻率的相互作用遠(yuǎn)比用正弦振動(dòng)僅對(duì)某些頻率或連續(xù)掃頻模擬上述振動(dòng)的影響更嚴(yán)酷、更真實(shí)、更有效。另外，用隨機(jī)振動(dòng)來(lái)研究產(chǎn)品的動(dòng)態(tài)特性和結(jié)構(gòu)的傳遞函數(shù)比用正弦振動(dòng)的方法更為簡(jiǎn)單和*。
Compared with the sinusoidal vibration, frequency domain random vibration test machine is wide, and there is a continuous spectrum, it can at the same time in the frequency of excitation, the interaction of various frequency than the sine vibration influence only on certain frequencies or continuous sweep frequency analog the vibration, more real, more severe more effective. In addition, the transfer function and dynamic characteristics of the structure of the product to use the random vibration of the sine vibration than method is more simple and superior.
隨機(jī)振動(dòng)和正弦振動(dòng)一樣能造成導(dǎo)線摩擦、緊固件松動(dòng)、活動(dòng)件卡死，從而破壞產(chǎn)品的連接、安裝和固定。當(dāng)隨機(jī)振動(dòng)激勵(lì)造成的應(yīng)力過(guò)大時(shí)，會(huì)使結(jié)構(gòu)產(chǎn)生裂紋和斷裂，特別在共振狀態(tài)下更為顯著。長(zhǎng)時(shí)間的隨機(jī)振動(dòng)，由于交變應(yīng)力所產(chǎn)生的累積損傷，會(huì)使結(jié)構(gòu)產(chǎn)生疲勞破壞。隨機(jī)振動(dòng)還會(huì)導(dǎo)致觸點(diǎn)接觸不良，帶電元件相互接觸或短路，焊點(diǎn)脫開(kāi)，導(dǎo)線斷裂，以及產(chǎn)生強(qiáng)電噪聲等，從而影響產(chǎn)品的正常工作，使產(chǎn)品性能下降、失靈甚至失效。
Random and sinusoidal vibrations can cause wires friction, loose fasteners, stuck, thus destroying the connection, installation and fixation of the product. When the random vibration caused by stress is too large, will make the structure crack and fracture, especially in the resonance state is more significant. Random vibration of long time, accumulated damage due to alternating stress produced, make the structure fatigue damage. Random vibration will result in bad contact, electrical components are in contact or short circuit, the solder joint disengagement, wire breaking, and strong noise, which affects the normal work of product, make the product performance, failure or failure.
隨機(jī)振動(dòng)試驗(yàn)機(jī)的描述：在隨機(jī)振動(dòng)試驗(yàn)中，由于電磁式振動(dòng)的質(zhì)點(diǎn)處于不規(guī)則的運(yùn)動(dòng)狀態(tài)，永遠(yuǎn)不會(huì)地重復(fù)，對(duì)其進(jìn)行一系列的測(cè)量，各次記錄都不一樣，所以沒(méi)有任何固定的周期。在任何確定的時(shí)刻，其振幅、頻率、相位都不能預(yù)先知道，因此就不可能用簡(jiǎn)單的周期函數(shù)和函數(shù)的組合來(lái)描述。
Random vibration test machine description: in random vibration test, because the particle electromagnetic vibration is in motion and irregular, never accuray repeat, a series of measurements were carried out on it, each record is not the same, so there is no fixed period. At any given moment, its amplitude, frequency, phase is not known in advance, so will not be a simple combination of periodic function and function to describe.
隨機(jī)過(guò)程：按功率譜譜密度頻譜的形狀，即按隨機(jī)過(guò)程的頻率結(jié)構(gòu)，產(chǎn)品現(xiàn)場(chǎng)出現(xiàn)的隨機(jī)振動(dòng)主要有下列形式。寬帶隨機(jī)振動(dòng)試驗(yàn)機(jī)是指振動(dòng)的能分布在一個(gè)較寬的頻率范圍內(nèi)的振動(dòng)，一般運(yùn)載工具，特別是空中運(yùn)載工具，如噴氣式飛機(jī)，其產(chǎn)生的振動(dòng)就屬于寬帶隨機(jī)振動(dòng)。
Stochastic process: according to the power spectrum density spectrum shape, namely according to the frequency of random process, random vibration of the scene of the main products have the following form. Random vibration test machine broadband refers to the vibration energy distribution in a wide frequency range of vibration, the general vehicles, especially the air vehicles, such as jet aircraft, vibration the belongs to the broadband random vibration.
窄帶隨機(jī)振動(dòng)是指振動(dòng)的能分布在一個(gè)較窄的頻率范圍內(nèi)的振動(dòng)，如螺旋槳飛機(jī)，由于螺旋槳葉轉(zhuǎn)動(dòng)時(shí)所帶動(dòng)的旋轉(zhuǎn)壓力場(chǎng)將產(chǎn)生窄帶隨機(jī)振動(dòng)，窄帶隨杉l的中心頻率是螺旋槳葉的通過(guò)頻率及其諧波（一般到4階），其窄帶帶寬為其通過(guò)頻率（中心頻率）及其各次諧波的5%(漂移）。寬帶+窄帶隨機(jī)振動(dòng)除窄帶隨機(jī)振動(dòng)外，更主要的是各種振源引起的寬帶隨機(jī)振動(dòng)。如安裝在腫帶車輛上和通過(guò)履帶午:輛運(yùn)輸?shù)漠a(chǎn)品，通常會(huì)經(jīng)受到以寬帶為主+窄帶的隨機(jī)振動(dòng)。寬帶隨機(jī)振動(dòng)來(lái)自車輛的基本運(yùn)動(dòng)、支承系統(tǒng)、路面不平。窄帶隨機(jī)振動(dòng)來(lái)自履帶拍擊地面的運(yùn)動(dòng)。
Narrow band random vibration is vibration energy distribution in a narrow frequency range of vibration, such as propeller aircraft, due to the rotating pressure driven propeller blade rotation field will have a narrow band random vibration, narrow band with center frequency L is fir propeller blade passing frequency and its harmonics (typically 4 to order), the narrow bandwidth of the frequency (frequency) and the harmonic 5% (drift). Broadband and narrowband random vibration in addition to narrow band random vibration, more important is the broadband random vibration caused by various sources. Such as the installation of the swollen with vehicles and by afternoon: track transportation products, often subjected to random vibration to broadband based + narrowband. The basic motion, broadband random vibration from the vehicle's supporting system, uneven pavement. Narrow band random vibration from the track on the ground motion.
寬帶隨機(jī)振動(dòng)+周期振動(dòng)寬帶隨機(jī)振動(dòng)+周期振動(dòng)是指在寬帶隨機(jī)振動(dòng)上疊加正弦振動(dòng)，直升飛機(jī)的振動(dòng)往往是在寬帶隨機(jī)振動(dòng)的簽礎(chǔ)上疊加很卨的正弦振動(dòng)。寬帶隨機(jī)振動(dòng)試驗(yàn)機(jī)來(lái)自直升飛機(jī)的各種振源，正弦振動(dòng)是由直升飛機(jī)的旋轉(zhuǎn)部件產(chǎn)生的，如主旋翼、尾旋翼、發(fā)動(dòng)機(jī)和變速箱的振動(dòng)。的國(guó)標(biāo)和IEC標(biāo)準(zhǔn)，將寬帶+窄帶隨機(jī)振動(dòng)與寬帶隨機(jī)振動(dòng)+周期振動(dòng)，稱為混合激勵(lì)振動(dòng)。在混合激勵(lì)振動(dòng)中，隨機(jī)分量用加速度譜密度表示，正弦分量用加速度幅值表示。
Broadband vibration band random vibration and random vibration and oscillation cycle refers to the superposition of sine vibration in broadband random vibration, the helicopter vibration are sinusoidal vibration superposition is improve in sign based broadband random vibration. Various sources of broad-band random vibration test machine from the helicopter, sinusoidal vibration is generated by the rotating components of helicopter, such as the main rotor, tail rotor vibration, the engine and transmission. The new national standard and IEC standard, the wideband and narrowband random vibration and random vibration and periodic vibration, called hybrid excitation. In the mixed excitation vibration, random component by acceleration spectral density representation, expressed by the acceleration amplitude of sinusoidal components.