高(gao)低(di)溫(wen)(wen)(wen)沖擊(ji)試(shi)(shi)驗(yan)(Thermal Shock Test) 是通(tong)過(guo)將樣品反復暴(bao)露于(yu)連(lian)續快(kuai)速變(bian)化的(de)高(gao)溫(wen)(wen)(wen)和(he)低(di)溫(wen)(wen)(wen)環(huan)境中,從而測試(shi)(shi)樣品在(zai)環(huan)境溫(wen)(wen)(wen)度突變(bian)條(tiao)件下(xia)(xia)的(de)耐受(shou)程度和(he)適應性試(shi)(shi)驗(yan)設備一(yi)般可(ke)以(yi)選擇采用兩(liang)個(ge)(ge)獨(du)立的(de)試(shi)(shi)驗(yan)箱(xiang),或一(yi)個(ge)(ge)溫(wen)(wen)(wen)度能夠快(kuai)速變(bian)化的(de)試(shi)(shi)驗(yan)箱(xiang)或一(yi)個(ge)(ge)帶有兩(liang)個(ge)(ge)腔室的(de)試(shi)(shi)驗(yan)箱(xiang)。試(shi)(shi)驗(yan)區(qu)域的(de)溫(wen)(wen)(wen)度驟變(bian)可(ke)以(yi)通(tong)過(guo)利用機械方法(fa)將測試(shi)(shi)架(jia)快(kuai)速地在(zai)高(gao)溫(wen)(wen)(wen)和(he)低(di)溫(wen)(wen)(wen)區(qu)域移動.或在(zai)保持測試(shi)(shi)架(jia)靜止的(de)情況下(xia)(xia)通(tong)過(guo)閘門開閉(bi)實現冷熱空氣的(de)交替來實現。溫(wen)(wen)(wen)度傳導介質可(ke)以(yi)是空氣,也(ye)可(ke)以(yi)是某些(xie)特定(ding)液體。本文(wen)只針對(dui)采用空氣介質的(de)高(gao)低(di)溫(wen)(wen)(wen)沖擊(ji)試(shi)(shi)驗(yan)進行討(tao)論。
通常(chang)情況下.轉換時(shi)間(jian)(jian){即(ji)圖(tu)1所示(shi)t2、試(shi)驗箱(xiang)(室)溫度(du)(du)恢復時(shi)間(jian)(jian)即(ji)圖(tu)1所示(shi)和溫度(du)(du)變換時(shi)間(jian)(jian)是評(ping)估高低(di)溫沖擊試(shi)驗箱(xiang)溫度(du)(du)驟變能(neng)力(li)的(de)重要依(yi)據。
檢測(ce)過程(cheng)的(de)試驗循環(huan)數(shu)應(ying)根據(ju)相關標準確(que)定(ding),如沒有(you)明確(que)規定(ding)。則建議至少運行5個(ge)循環(huan)對(dui)于第(di);次循環(huan)過程(cheng).可以得到一(yi)組升溫(wen)溫(wen)度變(bian)(bian)換(huan)時(shi)間(jian)(jian)(jian)t和降溫(wen)溫(wen)度變(bian)(bian)換(huan)時(shi)間(jian)(jian)(jian)t△升i(i=1.2.3.....)和降溫(wen)溫(wen)度變(bian)(bian)換(huan)時(shi)間(jian)(jian)(jian)t△降i(i= 1.2.3...)。后,以每(mei)次溫(wen)度變(bian)(bian)換(huan)時(shi)間(jian)(jian)(jian)的(de)計算(suan)結果平均值作為該設備(bei)溫(wen)度變(bian)(bian)換(huan)時(shi)間(jian)(jian)(jian)的(de)測(ce)量結果,即:
圖2為試(shi)驗(yan)(yan)過程中(zhong)單個(ge)循環的(de)(de)(de)(de)溫(wen)(wen)(wen)(wen)度(du)(du)(du)測(ce)試(shi)曲線,其形(xing)狀符合理論曲線證明該(gai)檢測(ce)方(fang)法是有效(xiao)可行的(de)(de)(de)(de)。根據(ju)上文規定的(de)(de)(de)(de)溫(wen)(wen)(wen)(wen)度(du)(du)(du)允許范圍(wei).選取(qu)每一(yi)段溫(wen)(wen)(wen)(wen)度(du)(du)(du)變(bian)化過程中(zhong)的(de)(de)(de)(de)起止時(shi)(shi)(shi)間(jian)點、根據(ju)它們之間(jian)包含(han)的(de)(de)(de)(de)采樣(yang)數(shu)據(ju)的(de)(de)(de)(de)個(ge)數(shu)。乘(cheng)以(yi)采樣(yang)間(jian)隔時(shi)(shi)(shi)間(jian)計算得到溫(wen)(wen)(wen)(wen)度(du)(du)(du)變(bian)換(huan)(huan)時(shi)(shi)(shi)間(jian)。本(ben)次試(shi)驗(yan)(yan)一(yi) 共(gong)進(jin)行了5個(ge)循環,得到了5組升溫(wen)(wen)(wen)(wen)溫(wen)(wen)(wen)(wen)度(du)(du)(du)變(bian)換(huan)(huan)時(shi)(shi)(shi)間(jian)和(he)降溫(wen)(wen)(wen)(wen)溫(wen)(wen)(wen)(wen)度(du)(du)(du)變(bian)換(huan)(huan)時(shi)(shi)(shi)間(jian)。計算結果如表2所示。溫(wen)(wen)(wen)(wen)度(du)(du)(du)變(bian)換(huan)(huan)時(shi)(shi)(shi)間(jian)平均值(zhi)為370s.測(ce)量(liang)結果重復性(xing)為18s。