大流速乳液泵中陶瓷材料的斷裂韌性測試與預測外文文獻翻譯、中英文翻譯、外文翻譯

大流速乳液泵中陶瓷材料的斷裂韌性測試與預測外文文獻翻譯、中英文翻譯、外文翻譯,流速,乳液,陶瓷材料,斷裂韌性,測試,預測,外文,文獻,翻譯,中英文 大流速乳液泵中陶瓷材料的斷裂韌性測試與預測 一 討論 1.1 化學成分和初始裂紋大小的影響 經(jīng)測試的 ZrO2-2 值比 ZrO2-1 值高出約 34%。ZrO2-1 和 ZrO2-2-2 之間的化學成分差異是 Fe2O3 和 Al2O3 的重量百分比，如表 2 所示。Fe2O3 是僅影響氧化鋅顏色的增色劑，對機械特性影響甚微。ZrO2-1 的 Al2O3 重量百分比為 0.75wt%，而 ZrO2-2 的權重百分比為 1.45wt%。Schierano等人發(fā)現(xiàn)，氧化鋁和氧化鋅的結合可以改善氧化鋅的機械性能，因為氧化鋅的老化效應較小。Nojima等人調查，KIC值隨著玻璃和氧化鋁陶瓷初始裂紋長度的增加而增加。對于 ZrO2-1 和 ZrO2-2-2 之間的 KIC 值差異，這似乎是合理的解釋。 1.2 SEPB 測試與其他方法的比較 從 SEPB 測試中獲得的實驗結果與從其他方法獲得的實驗結果相伴而行，如表 5 所示。從 SEPB 方法獲得的氧化鋁的 KIC 結果比從凹痕法和雪佛龍凹痕束獲得的氧化鋁結果大 34.1% 和 113%。SEPB 方法的過度預測可能與裂紋尖的鈍化效果有關。直通鋸缺口用于預裂紋的存在。然而，缺口不是一個尖銳的裂縫，它產生鈍化區(qū)附近的裂紋尖。尖銳裂紋的 KIC 與 KIC 的比較，在陶瓷材料參考中可以找到鈍器，這給出了公式10 ρ0是鈍裂紋的根半徑，r0 是裂紋尖附近的微裂紋大小。公式10 表示鈍化裂紋的斷裂韌性大于鋒利裂紋的斷裂韌性。辛普森也發(fā)現(xiàn)了類似的結果。他利用 SEPB 和 DCB 標本調查了 Al2O3 裂紋尖的鈍化效果。他發(fā)現(xiàn)，使用 SEPB 標本獲得的 KIC 值與 DCB 方法獲得的 0.5 毫米缺口寬度之比約為 1.21。 1.3 XFEM 過度估制的原因 應用于標本的實驗負荷是時間依賴的。最大應用負載 Pf 用于使用方程 1 來計算值斷裂韌性。簡言之，在這項研究中，排量率被用作裝載條件，這被認為是造成XFEM預測過高的原因。另一方面，為了消除打孔標本接觸之間摩擦對數(shù)值結果的影響，認為打孔標本接觸幾乎無摩擦，從而導致非物理接觸行為。因此，今后XFEM分析應涉及現(xiàn)實的接觸行為。 二 包括備注 已對三種陶瓷材料進行了按照ISO15732-2003標準使用SEPB標本的斷裂韌性測試。試驗結果以魏布爾分布功能兩個參數(shù)為特征。SEM對ZrO2-1材料的觀察表明，斷裂模式主要以顱際和跨顱裂開裂的混合物為主。XFEM 方法對骨折韌性值的預測過高，分別為 10.4%、24.8% 和 25.6%，高于 ZrO2-1、ZrO2-2 和 Al2O3 的測試結果。討論了ZrO2-1和ZrO2-2測試中化學成分和初始裂紋大小對 SEPB 測試的影響。在比較 SEPB 方法與其他測試方法時，裂紋尖的鈍化效果被認為是 SEPB 測試結果相對較大的一個原因。在加載條件和接觸假設方面討論了從 XFEM 分析中獲得的 KIC 值預測過高的可能原因。  Fracture Toughness Testing and Prediction for Ceramic Materials Using in Large-Flow-Rate Emulsion Pumps 一Discussions 1.1 Influence of Chemical Composition and Initial Crack Size The tested KIC values of ZrO2-2 are about 34% higher than those of ZrO2-1. The differences in the chemical compositions between ZrO2-1 and ZrO2-2 are the weight percent of Fe2O3 and Al2O3, as shown in Table 2. Fe2O3 is the colourant additions which only affects the colour of zirconia and has little effect on the mechanical properties . The weight percent of Al2O3 is 0.75wt% for ZrO2-1, while this value increases to 1.45wt% for ZrO2-2. Schierano et al have found that the combination of alumina and zirconia allows the improvement of the mechanical performance of zirconia, due to the minoring the ageing effect of zirconia. Nojima et al have investigated that the KIC value increases with an increase in the length of initial crack for both a glass and an alumina ceramic. It seems to be reasonable explanations for the differences in the KIC values between ZrO2-1 and ZrO2-2. 1.2 Comparison Between SEPB Tests and Other Methods The experimental results obtained from SEPB tests were companied with those obtained from other methods, as shown in Table 5. The KIC result of alumina obtained from SEPB method was 34.1% and 113% larger than those obtained from indentation method and chevron notched beam . The overprediction for the SEPB method may be related to the blunting effect of crack-tip. The straight-through saw notch was used for the presence of pre-crack. However, the notch was not a sharp crack, which produces the blunting zone in the vicinity of the crack tip. The comparison between the KIC for a sharp crack and KIC, blunt can be found in Reference for ceramic materials, which gives in Equation 10 Where ρ0 is the root radius of the blunt crack and r0 is the microcrack size near the crack tip. Equation 10 indicates the fracture toughness for the blunting crack is larger than that for a sharp crack. Similar results were also found by Simpson . He investigated the blunting effect of crack-tip for Al2O3 using SEPB and DCB specimens. He found that the ratio of KIC value obtained using SEPB specimen with 0.5mm notch width to that obtained from DCB method is about 1.21. 1.3 Reasons for XFEM Overprediction The experimental loads applied to the specimens were time-dependent. The maximum applied loads, Pf , were used for calculating the values fracture toughness by the use of Equation 1. For simplicity, the displacement rates were used as loading condition in this study, which would be believed to contribute to the XFEM overpredictions. On the other hand, the punch-specimen contact was assumed to be nearly frictionless, in order to eliminate the influence of friction between punch-specimen contact on the numerical results, which would result in nonphysical contact behaviour. Hence, the realistic contact behaviour should be involved for the XFEM analyses in the future. 二Concluding Remarks Fracture toughness tests using SEPB specimens according to ISO15732-2003 standard have been carried out for three ceramic materials. The test results were characterized in terms of the two parameter Weibull distribution function. The SEM observations of ZrO2-1 material indicate that the fracture mode was dominated by a mixture of intergranular and transgranular cracking. The XFEM approach overpredicts the fracture toughness values, which are 10.4%, 24.8% and 25.6%, higher than those obtained from the tests for ZrO2-1, ZrO2-2 and Al2O3, respectively. The influences of chemical composition and initial crack size on the SEPB tests were discussed for ZrO2-1 and ZrO2-2. In comparing SEPB method with the other test methods, the blunting effect of crack-tip was considered as a reason that the SEPB test results are relatively large. The possible reasons for the overprediction of KIC values obtained from XFEM analyses were discussed in the aspect of loading conditions and contact assumptions.