【摘要】：隨著人類科學技術的不斷發(fā)展與進步,人類對清潔能源的需求量也越來越大。熱電材料作為一種新型功能材料,能夠在電能和熱能之間實現(xiàn)能量相互轉化。但是熱電材料在服役期間常因熱沖擊而產(chǎn)生機械失效甚至斷裂,因此對熱電材料的熱沖擊應力及斷裂分析是非常必要的。本論文通過解析法對熱電材料內(nèi)部的應力場及斷裂特性進行了理論分析,完成了對單層和層合熱電材料板的熱沖擊應力和斷裂力學分析。首先通過熱電材料的物理本構方程獲得溫度場,再根據(jù)熱彈性力學的相關理論求得應力場,最后以Be2Te3基熱電材料為例進行分析。發(fā)現(xiàn)在熱沖擊初始階段熱應力比較大,然后熱應力隨著時間的增加而逐漸減小。在瞬態(tài)過程中單層熱電材料板的最大熱應力發(fā)生在冷端面,而層合熱電材料板的最大熱應力發(fā)生在熱端面。另外對含有邊緣裂紋單層熱電材料板完成了斷裂力學分析,通過權函數(shù)法求得應力強度因子,發(fā)現(xiàn)板的厚度越大,相應的應力強度因子也就越大。然后通過數(shù)值法對含有邊緣裂紋單層熱電材料板所能承受的熱沖擊阻力進行了研究,發(fā)現(xiàn)板的厚度越大,其所能承受的熱沖擊阻力就越小。因此從斷裂力學的角度來看,同樣條件下薄板更具有良好的斷裂力學性能。最后,通過數(shù)值擬合得到了計算熱電材料所能承受的熱沖擊阻力的經(jīng)驗公式,此公式可以用于指導熱電器件的斷裂力學可靠性設計。同時,本研究對熱電器件工作期間發(fā)生的機械失效也產(chǎn)生更加深入的理解。
[Abstract]:With the development and progress of science and technology, the demand for clean energy is increasing. As a new functional material, thermoelectric material can transform energy between electric energy and heat energy. However, mechanical failure and even fracture of thermoelectric materials are often caused by thermal shock during service, so it is necessary to analyze thermal shock stress and fracture of thermoelectric materials. In this paper, the stress field and fracture characteristics of thermoelectric materials are analyzed by analytical method, and the thermal shock stress and fracture mechanics of single-layer and laminated thermoelectric plates are analyzed. First, the temperature field is obtained by the physical constitutive equation of thermoelectric material, then the stress field is obtained according to the theory of thermoelastic mechanics. Finally, the thermoelectric material based on Be2Te3 is analyzed as an example. It is found that the thermal stress is relatively large in the initial stage of thermal shock and then decreases with the increase of time. In the transient process, the maximum thermal stress of single-layer thermoelectric plate occurs on the cold end surface, while the maximum thermal stress of laminated thermoelectric plate occurs on the hot end surface. In addition, the fracture mechanics analysis of single-layer thermoelectric material with edge cracks is carried out. The stress intensity factor is obtained by the weight function method. It is found that the greater the thickness of the plate, the greater the corresponding stress intensity factor. Then the thermal shock resistance of single-layer thermoelectric plate with edge cracks is studied by numerical method. It is found that the greater the thickness of the plate, the smaller the thermal shock resistance it can withstand. Therefore, from the point of view of fracture mechanics, the thin plate has better fracture mechanical properties under the same conditions. Finally, an empirical formula for calculating the thermal shock resistance of thermoelectric materials is obtained by numerical fitting, which can be used to guide the reliability design of fracture mechanics of thermoelectric devices. At the same time, this study also produces a deeper understanding of the mechanical failure of thermoelectric devices.
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TB34

【參考文獻】

相關期刊論文 前1條

1 王子建;何俊佳;尹小根;;高壓限流型熔斷器熱電耦合瞬態(tài)溫度場的計算[J];高壓電器;2006年06期

相關碩士學位論文 前1條

1 任小川;納米尺度薄膜力—熱耦合載荷下屈曲的實驗研究[D];天津大學;2007年

，

本文編號：2338102