本文關(guān)鍵詞：基于Cocks-Ashby模型的多軸蠕變?cè)O(shè)計(jì)準(zhǔn)則的局限性及其修正　出處：《機(jī)械工程學(xué)報(bào)》2017年16期 　論文類型：期刊論文

  更多相關(guān)文章： 黏塑性 多軸蠕變 Cocks-Ashby模型 簡(jiǎn)化模型修正

【摘要】：多軸應(yīng)力狀態(tài)下結(jié)構(gòu)的蠕變變形分析是高溫裝備強(qiáng)度設(shè)計(jì)的理論基礎(chǔ)。經(jīng)典的Cocks-Ashby多軸蠕變孔洞長(zhǎng)大模型及其簡(jiǎn)化模型存在著嚴(yán)苛的適用條件及局限性,僅適用于描述高溫低應(yīng)力環(huán)境下以晶間蠕變孔洞長(zhǎng)大過程為材料蠕變損傷主要形式的蠕變變形行為。根據(jù)其簡(jiǎn)化解得到的用于單-多軸蠕變延性換算的多軸蠕變因子則存在著在低三軸應(yīng)力度段給出的計(jì)算值較試驗(yàn)值偏小的問題。在基于WITCHMANN對(duì)該問題修正工作的基礎(chǔ)上,通過合理的進(jìn)一步優(yōu)化,一個(gè)新的多軸蠕變因子被得出。將新修正因子應(yīng)用在一個(gè)處于簡(jiǎn)化恒定應(yīng)力場(chǎng)中的發(fā)動(dòng)機(jī)熱端葉片算例上,計(jì)算出恒載下葉片的等效多軸蠕變應(yīng)變分布。有限元計(jì)算結(jié)果表明在葉片模型的葉根中部區(qū)域存在著較大的三軸應(yīng)力度及較小的多軸蠕變因子,使得葉根中部原本應(yīng)變不太明顯的區(qū)域也產(chǎn)生了較大的等效多軸蠕變應(yīng)變,導(dǎo)致葉片計(jì)算出的潛在失效面積較未經(jīng)多軸蠕變因子修正前顯著增加。
[Abstract]:The multiaxial stress state of the structure under the creep deformation analysis is the theoretical basis for high temperature equipment and strength design. Multi axial creep cavity classic Cocks-Ashby growth model and its simplified model is suitable for harsh conditions and limitations, only suitable for describing the creep deformation behavior at high temperature and low stress intergranular creep void growth process mainly in the form of material creep the damage of environment. According to the simplified solution for the multi axial creep factor single - multiaxial creep ductility conversion exists should be calculated intensity values given by the experimental value than some small question in the low three axis. Based on WITCHMANN on the issue of the rectification work, through further optimized, a new multiaxial creep factor was obtained. The new correction factor used in a simplified constant stress field in the engine hot end blade example, calculated under dead load of blade etc. Effect of multi axial creep strain distribution. The finite element calculation results show that in the central region of the blade root blade model has three axis should be multi axial creep strength and smaller factors larger, makes the leaf root central strain less obvious areas had also produced a multi axial creep strain larger equivalent, resulting in potential failure leaf area calculation that is without the multiaxial creep factor correction increased significantly.

【作者單位】： 華東理工大學(xué)承壓系統(tǒng)與安全教育部重點(diǎn)實(shí)驗(yàn)室;
【基金】：國(guó)家自然科學(xué)基金資助項(xiàng)目(51325504,51475167)
【分類號(hào)】：O344.6
【正文快照】： 0前言1蠕變是高溫設(shè)備中發(fā)生的一種依賴于溫度、載荷和服役時(shí)間的時(shí)效塑性變形行為,屬于黏塑性范疇。其產(chǎn)生機(jī)理和演化行為表現(xiàn)出強(qiáng)烈的溫度和載荷相關(guān)性,需要合理的模型和函數(shù)方程去描述。例如,在中等溫度和應(yīng)力條件下,純金屬、合金等多晶體材料中發(fā)生的由位錯(cuò)攀移導(dǎo)致的蠕變，

本文編號(hào)：1426799