[标准] IEC 68-2-64 试验方法 Fh：宽频随机振动(数位控制)及指引 [复制链接]档

[ 标准 excel标准偏差excel标准偏差函数exl标准差函数国标检验抽样标准表免费下载红头文件格式标准下载 ] IEC 68-2-64 试验方法 Fh：宽频随机振动(数位控制)及指引 [复制链接]档 範圍 本試驗法適用於運輸或使用過程中遭遇隨機振動之元件、裝備或產品。 本試驗法主要針對無包裝之試件及含運輸箱之試件，如為後者，則運輸箱可 視為試件本體之一部份。 本試驗共有兩種方法，分述如下: , 試驗方法Ι通常僅用於驗證試件在隨機振動環境之存活能力;如在相關 規範中另有規定，可於振動試驗之前或後，以正弦或隨機方式激振，進 行振動響應調查。 , 試驗方法?通常僅用於調查試件之振動響應;可在隨機振動驗證之前 (或後，如相關規範要求)，以正弦或隨機方式激振，求得試件在最窄-3dB 共振頻寬時之共振頻率。 限制 本試驗法不適用於運輸或使用過程遭遇簡諧(harmonic)振動之元件、裝備或 產品。 測試步驟 , 試驗前試件應依相關規範之規定執行目視檢查、電性及機械檢驗。 , 按規格依序在三相互垂直軸向執行試驗(軸向另有規定者除外)，且其嚴厲度應在相 關規範中明定。其程序如下: , 初始振動響應調查: 依相關規範規定以正弦或隨機方式激振，求得試件之 共振頻率及最窄的-3dB共振頻寬，執行細節請參考 第7.(2)節。對試驗方法Ι而言，若相關規範未要求 則可省略此步驟。 , 以低位準激振方式進行等化(equalization)程序: 在執行相關規範所訂位準之振動試驗前，振動控制系 統須以較低位準之試振程序，使達到等化狀態，亦即 試件所受振動量在規格之要求容差內。表1為試振位 準與時間限制。 , 依相關規範規定之試驗規格進行試驗，主要參數如下: 試驗頻率範圍。 ASD(acceleration spectral density)位準。 隨機振動之頻譜形狀。 試驗時間。 , 在隨機振動試驗中，依相關規範規定對試件進行功能檢驗。 如相關規範有要求，可進行最終振動響應調查。若所求得之共振頻率與初始 振動響應調查結果不同，則可能是因試件特性改變或發生失效所致。 , 俟試件回復至原來狀況後，應執行目視檢查、電性及機械檢驗。 測試條件 , 試件固定方式 除相關規範另有規定外，試件固定應遵循IEC 68-2-47之規定。 , 振動嚴厲度 振動嚴厲度係由頻率範圍、ASD位準、頻譜形狀及試驗時間表示。決定上述 參數的方式為: and due diligence evaluations article 22nd head office, branch (jurisdiction), risk management, marketing management branch within the Department's credit business person assumed responsibility for the supervision and inspection and due diligence evaluations. Article 23rd, Head Office, branches (jurisdiction), risk management, Marketing Management Department through on-site and off-site inspection, investigation report, interviews with investigators for pre-loan investigation work by way of conducting supervision and inspection, quality evaluation pre-loan investigation work, and based on the evaluation results, the implementation of diversity management. 24th the control and inspection (a) the implementation of the credit system: there is no breach of credit policy relating to the granting of credit and the head office; (B) dual credit rating: timeliness of ratings, whether the provisions of the rating, rating results are accurate; (C) the survey contents: data collection is complete, report writing is comprehensive, indicators analysis is objective, real, conclusions and the facts are consistent and reasonable; (D) double implementation of investigations system: practical implementation of double system; (E) other supervision and inspection of the contents. 25th due diligence evaluation offices and branches (jurisdiction), risk management, Marketing Management Department agreed to carry out pre-loan investigation supervision and inspection work, evaluate whether investigators due diligence to determine whether the exemption should be. Investigators should be compatible with. Due diligence assessment should be based on the fact that, following the principles of objectivity, impartiality and fairness. Article 26th head 參照5.(2)b.,5.(2)e.之建議值。 由試件之已知環境推導而得者。 由類似產品之環境規格推導而得者。 ASD 位準(g2/Hz) 0.005 0.01 0.05 0.1 0.5 1.0 5.0 10.0 頻率範圍:如表2所示。 , 頻譜形狀 試驗頻譜可依照圖1之形狀決定;亦可由相關規範制訂ASD位準與頻率對 應之頻譜曲線，但頻率與位準值儘可能選用第5.(2)節與第5.(3)節之建議值。 , 試驗時間(每一振動軸向，容差0,+5 %): 1分鐘， 3分鐘，10分鐘，30分鐘，100分鐘，300分鐘 , 振動時之運動需求 在試件夾持點的運動大體上應符合規範之規定，且其瞬間加速度須呈直線性 (rectilinear)、隨機及常態(normal)分布。 在試件參考點的瞬間加速度值應為常態分布，其容差要求如圖2所示。若為 虛擬參考點，則應將上述容差要求之對象改為所有用以控制ASD頻譜之檢 查點。 應在相關規範中明訂驅動訊號之波高率(crest factor)及其截斷位準(clipping level)，但不可低於2.5，亦即訊號峰值至少為均方根值之2.5倍。 檢查點之側向振動位準不可超過振動軸向ASD位準5dB，也不可超過軸向 振動均方根值的50%。對於較小試件可將限制加嚴，例如，將上述5dB限 制降為3dB。對於大型或較重試件，可能無法滿足上述限制，因此，須在相 關規範中規定: 於試驗報告中記載所有超過上述限制之側向運動。 已知對試件不造成危害之側向運動，可不監測。 , 試驗容差與頻譜形狀要求 控制系統或其輸入設備中的類比組件會造成儀器誤差，因此在振動規格之頻 率範圍內(f1,f2)，檢查點與參考點於振動軸向測得之 ASD位準可有?3dB 之容差，但隨機與偏移誤差並不包括在內。使用試驗方法?時，應在相關規 範明訂允許之最高偏移誤差。中国可靠性网: 在頻率範圍f1,f2 內所測得或算出之加速度均方根值，應在規格之?10% 容差內，此一要求對單點或多點控制均適用。 上述之ASD位準與均方根植限制在大型或較重試件時可能無法滿足，因此 可在相關規範中應訂較寬之容差。 振動頻譜之初始斜率?6dB，末端斜率?-24dB(如圖1)。 , 頻率解析度 應儘量提高控制或 分析 定性数据统计分析pdf销售业绩分析模板建筑结构震害分析销售进度分析表京东商城竞争战略分析 系統之頻率解析度，以降低ASD位準測示值和真值 之誤差，可依試驗方法選用頻率解析度如下: , 試驗方法Ι:如表3所示。 , 試驗方法? 頻率解析度(Be)須由頻率響應調查所求得之 -3dB 共振頻寬 Br 推導而得， 公式如下: and due diligence evaluations article 22nd head office, branch (jurisdiction), risk management, marketing management branch within the Department's credit business person assumed responsibility for the supervision and inspection and due diligence evaluations. Article 23rd, Head Office, branches (jurisdiction), risk management, Marketing Management Department through on-site and off-site inspection, investigation report, interviews with investigators for pre-loan investigation work by way of conducting supervision and inspection, quality evaluation pre-loan investigation work, and based on the evaluation results, the implementation of diversity management. 24th the control and inspection (a) the implementation of the credit system: there is no breach of credit policy relating to the granting of credit and the head office; (B) dual credit rating: timeliness of ratings, whether the provisions of the rating, rating results are accurate; (C) the survey contents: data collection is complete, report writing is comprehensive, indicators analysis is objective, real, conclusions and the facts are consistent and reasonable; (D) double implementation of investigations system: practical implementation of double system; (E) other supervision and inspection of the contents. 25th due diligence evaluation offices and branches (jurisdiction), risk management, Marketing Management Department agreed to carry out pre-loan investigation supervision and inspection work, evaluate whether investigators due diligence to determine whether the exemption should be. Investigators should be compatible with. Due diligence assessment should be based on the fact that, following the principles of objectivity, impartiality and fairness. Article 26th head Be = a Br ，其中 a 值小於 1 選用係數 a 時須考慮偏移誤差 Eb，如表4所示。 , 統計精確度 隨機振動試驗之統計精確度係以其統計自由度( Nd)決定，通常 Nd應高於120，其公式如下: Nd = 2 Be Ta 其中， Be 為頻率解析度， Ta為有效平均時間。 在不同信賴度下，精確度與自由度之關係為卡方(Chi- square)分布。 , 試驗設置 試件應以正常安裝姿態固定於試驗平台上執行試驗，有關試件固定需求詳見IEC 68-2-47之規定。 夾持點、檢查點皆應遵照相關規範之規定。 數位控制之隨機振動系統(包含數位控制系統、功率放大器、夾具及振動機等)。 正弦振動之控制系統(若相關規範中要求以正弦振動調查試件響應)。 其他 , 夾持點、檢查點、參考點、虛擬點及響應點 夾持點為試件與夾具或振動台直接連接處，通常試件在操作時即固定於此處。若採用試件操作時實際固定結構之部份為夾具，則夾持點應為該結構與振動台之連接點，不再是該結構與試件之接合點。 檢查點位於夾具、振動台或試件上，應儘量靠近試件之夾持點且與之堅固連接。若僅有四個以下的夾持點，則每個夾持點都可選為檢查點;若有四個以上的夾持點時，則試驗規範中應指明四個夾持點作為代表的檢查點。 參考點係選自檢查點，並以其訊號控制振動試驗，使達到規格之要求。參考點亦可能是虛擬點，例如，參考點ASD數值可定義為多個檢查點ASD數值之平均。建議在大試件或複雜結構時，以虛擬點為參考點。 虛擬點並非實際量測點，該點所得數值通常是多個量測點之運算結果。 響應點位於試件上，不同於檢查點或參考點，主要用以振動響應調查。 , 振動響應調查 在試驗方法Ι(如規範要求)，振動響應調查目的在探討試件之機械或結構動態效應。而在試驗方法?目的在探討共振及最小的-3dB頻寬( Br)，以便求得頻率解析度( Be)。 為避免響應調查時因共振節點(nodal point)而疏漏某些共振頻率，建議在相關規範中明訂多個響應量測點。此外，量測時應避免因量測設置而改變試件動態特性(如加速儀過重);應注意非線性共振時，共振頻率及放大倍率都有變動之可能。 振動響應調查可依其激振方式分為正弦掃描與隨機兩種: , 正弦掃描激振 掃描方式 於頻率範圍(f1,f2)內，以不超過1 octave/min 之 速率進行掃描，其他可參考IEC 68-2-6。 Br 與 Be 之計算 將掃描時於不同頻率測得之響應振幅除以輸入振幅， 可求出頻率響應曲線，並從而求得共振頻率與最小的 and due diligence evaluations article 22nd head office, branch (jurisdiction), risk management, marketing management branch within the Department's credit business person assumed responsibility for the supervision and inspection and due diligence evaluations. Article 23rd, Head Office, branches (jurisdiction), risk management, Marketing Management Department through on-site and off-site inspection, investigation report, interviews with investigators for pre-loan investigation work by way of conducting supervision and inspection, quality evaluation pre-loan investigation work, and based on the evaluation results, the implementation of diversity management. 24th the control and inspection (a) the implementation of the credit system: there is no breach of credit policy relating to the granting of credit and the head office; (B) dual credit rating: timeliness of ratings, whether the provisions of the rating, rating results are accurate; (C) the survey contents: data collection is complete, report writing is comprehensive, indicators analysis is objective, real, conclusions and the facts are consistent and reasonable; (D) double implementation of investigations system: practical implementation of double system; (E) other supervision and inspection of the contents. 25th due diligence evaluation offices and branches (jurisdiction), risk management, Marketing Management Department agreed to carry out pre-loan investigation supervision and inspection work, evaluate whether investigators due diligence to determine whether the exemption should be. Investigators should be compatible with. Due diligence assessment should be based on the fact that, following the principles of objectivity, impartiality and fairness. Article 26th head -3dB頻寬( Br)，再依第5.(5)b.節公式算出頻率解析度 Be。 一般要求在最小的-3dB頻寬中，至少應包含五條頻譜線。 , 隨機激振方式 以各頻率ASD位準皆近似之頻譜作為激振輸入訊號。 , 控制方式: 單點控制 單點控制通常用於小型 或結實之試件，其控制回 饋訊號來自單一參考點。 多點控制 多點控制通常用於大型 或複雜之試件，控制回饋 訊號來自多個參考點，控 制方式有以下兩種: 平均方式:以所有檢查點測得頻譜在各 頻率之算術平均為參考頻譜。 極值方式:以所有檢查點測得頻譜在各 頻率之最大值為參考頻譜。 , 驅動訊號之統計特性 機率分布 本標準中要求振動試驗之瞬間控制驅 動訊號屬常態分布，其主要原因為: 以現今知識水平而言，對 常態分布特性有較深入 之瞭解，對於其模型建立 及結果統計較能掌握。 振動試驗中訊號歷經多 重濾波過程，可視之為足 夠多個隨機變數之和，由 中央極限定理(central limit theorem)可知其 分布應為常態。 任何常態分布變數經線 性轉換後，分布仍為常 態。 隨機振動現場所量得資 料近似於常態分布。 , 波高率(crest factor)或截斷位準(clipping level) 波高率或截斷位準係用以限制數位控 制系統輸出之驅動訊號，用意在: 保護振動系統，截除過大之驅動訊號。 and due diligence evaluations article 22nd head office, branch (jurisdiction), risk management, marketing management branch within the Department's credit business person assumed responsibility for the supervision and inspection and due diligence evaluations. Article 23rd, Head Office, branches (jurisdiction), risk management, Marketing Management Department through on-site and off-site inspection, investigation report, interviews with investigators for pre-loan investigation work by way of conducting supervision and inspection, quality evaluation pre-loan investigation work, and based on the evaluation results, the implementation of diversity management. 24th the control and inspection (a) the implementation of the credit system: there is no breach of credit policy relating to the granting of credit and the head office; (B) dual credit rating: timeliness of ratings, whether the provisions of the rating, rating results are accurate; (C) the survey contents: data collection is complete, report writing is comprehensive, indicators analysis is objective, real, conclusions and the facts are consistent and reasonable; (D) double implementation of investigations system: practical implementation of double system; (E) other supervision and inspection of the contents. 25th due diligence evaluation offices and branches (jurisdiction), risk management, Marketing Management Department agreed to carry out pre-loan investigation supervision and inspection work, evaluate whether investigators due diligence to determine whether the exemption should be. Investigators should be compatible with. Due diligence assessment should be based on the fact that, following the principles of objectivity, impartiality and fairness. Article 26th head 波高率為振幅峰值與均方根值之比，在 本標準要求限制在2.5以上，使隨機振 動之振幅分布符合常態分布的99%。 當規格要求在低頻(例如20Hz)須具高 ASD位準時，波高率過高可能使振動系 統無法達到規格之振幅需求，因此須在 相關規範中降低波高率需求。此外，若 要求低頻有顯著的ASD位準時，波高率 即使限制在2.5以上，其振幅可能仍然 不是常態分布。 , 試驗誤差 , 儀具誤差(instrument error) 此誤差來自振動訊號量測系統與數位轉換程序，由加速儀(accelerometer)、電纜線、放大器(調節加速儀訊號用)、反膺頻濾波器(anti-aliasing filter)類比數位轉換器(analog digital converter)等包含類比組件之儀具所組成。 應將此誤差自試驗總容差中扣除。 , 隨機誤差(random error, Er) 隨機誤差與振動頻譜分析時之樣本數有關。對線性平均(linear average)而言，統計之自由度(d)約可 N表為: Nd = 2 Be Ta = 2 n 其中 n 為發生在有效平均時間( Ta)內之平均次數。對指數平均(exponential average)而言，統計之自由度約可表為: Nd = 2 n ( 2 p - 1 ) 其中 1/ p 為每次平均時加入訊號中的新成分比例， n 為發生在有效平均時間內之線性平均次數。 若ASD頻譜之自由度為 Nd ，並要求其精確信賴度為a， 則頻譜之真值Gxx( f )與估算值Gxx( f )存有如下關係: 其中c2(.)為卡方(Chi-square)分布函數。依此式作圖如圖3所示。 , 偏移誤差(bias error, Eb) 分析振動響應頻譜時，若頻率之解析度不足，則在頻譜中形狀較陡峭處，將產生過低(峰)或過高(谷)之偏移誤差。對振動控制系統而言，由於無法掌握試件試驗時之振動實況，造成控制補償死角。頻率解析度不足之偏移誤差，表示如下: 其中 k為小於1之常數， W與時間窗函數有關，如表5所示。 提高分析頻率解析度的唯一方法為增加解析時間，但會產生分析時間增長及控制遲緩等副作用。 and due diligence evaluations article 22nd head office, branch (jurisdiction), risk management, marketing management branch within the Department's credit business person assumed responsibility for the supervision and inspection and due diligence evaluations. Article 23rd, Head Office, branches (jurisdiction), risk management, Marketing Management Department through on-site and off-site inspection, investigation report, interviews with investigators for pre-loan investigation work by way of conducting supervision and inspection, quality evaluation pre-loan investigation work, and based on the evaluation results, the implementation of diversity management. 24th the control and inspection (a) the implementation of the credit system: there is no breach of credit policy relating to the granting of credit and the head office; (B) dual credit rating: timeliness of ratings, whether the provisions of the rating, rating results are accurate; (C) the survey contents: data collection is complete, report writing is comprehensive, indicators analysis is objective, real, conclusions and the facts are consistent and reasonable; (D) double implementation of investigations system: practical implementation of double system; (E) other supervision and inspection of the contents. 25th due diligence evaluation offices and branches (jurisdiction), risk management, Marketing Management Department agreed to carry out pre-loan investigation supervision and inspection work, evaluate whether investigators due diligence to determine whether the exemption should be. Investigators should be compatible with. Due diligence assessment should be based on the fact that, following the principles of objectivity, impartiality and fairness. Article 26th head 表1:試振位準與時間限制 試振之均方根值 時間限制 低於試驗規格均方根值的 -12dB 無時間限制 介於試驗規格均方根值的 -12dB,-6dB間間 低於1.5倍的試驗時間 介於試驗規格均方根值的 -6dB,0dB之間 低於0.1倍的試驗時間 表2:試驗之頻率範圍 f1 (Hz) f2 (Hz) 1 100 5 500 20 2,000 50 5,000 表3:試驗方法Ι之頻率解析度 試驗之頻率範圍 頻率解析度之上限值(Hz) f1 (Hz) f2 (Hz) 1 100 0.5 5 500 2.5 20 2,000 10 50 5,000 25 表4:係數 a 與偏移誤差Eb 時間窗函數 Eb(dB) ?3 ?2 ?1 ?0.5 rectangular 係數 a 0.87 0.75 0.56 0.4 triangular 係數 a 0.65 0.56 0.42 0.3 Hamming 0.54+0.46 cos( T) 係數 a 0.64 0.55 0.41 0.29 Hanning 0.5+0.5 cos( T) 係數 a 0.58 0.5 0.37 0.26 Blackman-Harris (4 項係數) 係數 a 0.43 0.37 0.28 0.2 表5:係數 W 與時間窗函數 時間窗函數 W and due diligence evaluations article 22nd head office, branch (jurisdiction), risk management, marketing management branch within the Department's credit business person assumed responsibility for the supervision and inspection and due diligence evaluations. Article 23rd, Head Office, branches (jurisdiction), risk management, Marketing Management Department through on-site and off-site inspection, investigation report, interviews with investigators for pre-loan investigation work by way of conducting supervision and inspection, quality evaluation pre-loan investigation work, and based on the evaluation results, the implementation of diversity management. 24th the control and inspection (a) the implementation of the credit system: there is no breach of credit policy relating to the granting of credit and the head office; (B) dual credit rating: timeliness of ratings, whether the provisions of the rating, rating results are accurate; (C) the survey contents: data collection is complete, report writing is comprehensive, indicators analysis is objective, real, conclusions and the facts are consistent and reasonable; (D) double implementation of investigations system: practical implementation of double system; (E) other supervision and inspection of the contents. 25th due diligence evaluation offices and branches (jurisdiction), risk management, Marketing Management Department agreed to carry out pre-loan investigation supervision and inspection work, evaluate whether investigators due diligence to determine whether the exemption should be. Investigators should be compatible with. Due diligence assessment should be based on the fact that, following the principles of objectivity, impartiality and fairness. Article 26th head rectangular 1.00 triangular 1.33 Hamming [ 0.54+0.46 cos( T )] 1.36 Hanning [ 0.5+0.5 cos( T ) ] 1.50 Blackman-Harris (4項係數) 2.00 and due diligence evaluations article 22nd head office, branch (jurisdiction), risk management, marketing management branch within the Department's credit business person assumed responsibility for the supervision and inspection and due diligence evaluations. Article 23rd, Head Office, branches (jurisdiction), risk management, Marketing Management Department through on-site and off-site inspection, investigation report, interviews with investigators for pre-loan investigation work by way of conducting supervision and inspection, quality evaluation pre-loan investigation work, and based on the evaluation results, the implementation of diversity management. 24th the control and inspection (a) the implementation of the credit system: there is no breach of credit policy relating to the granting of credit and the head office; (B) dual credit rating: timeliness of ratings, whether the provisions of the rating, rating results are accurate; (C) the survey contents: data collection is complete, report writing is comprehensive, indicators analysis is objective, real, conclusions and the facts are consistent and reasonable; (D) double implementation of investigations system: practical implementation of double system; (E) other supervision and inspection of the contents. 25th due diligence evaluation offices and branches (jurisdiction), risk management, Marketing Management Department agreed to carry out pre-loan investigation supervision and inspection work, evaluate whether investigators due diligence to determine whether the exemption should be. Investigators should be compatible with. Due diligence assessment should be based on the fact that, following the principles of objectivity, impartiality and fairness. Article 26th head