過(guò)程中熱應(yīng)力場(chǎng)的影響
(中南大學(xué) 粉末冶金國(guó)家重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083)
摘 要: 測(cè)量以純樹(shù)脂炭、粗糙層熱解炭和光滑層熱解炭為基體的3種炭/炭復(fù)合材料的熱膨脹系數(shù)，并采用有限元分析軟件，模擬這3種炭/炭復(fù)合材料在飛機(jī)正常著陸能量條件下的熱應(yīng)力場(chǎng)，研究熱膨脹系數(shù)對(duì)炭/炭復(fù)合材料熱應(yīng)力場(chǎng)及其摩擦性能的影響。結(jié)果表明：3種炭/炭復(fù)合材料在z方向上的熱膨脹系數(shù)大于在x和y方向的，且熱膨脹系數(shù)均隨著溫度的升高而逐漸增大，其中，基體為粗糙層熱解炭的炭/炭復(fù)合材料的熱膨脹系數(shù)最小，純樹(shù)脂炭試樣的次之，光滑層熱解炭試樣的最大；在制動(dòng)過(guò)程中，炭/炭復(fù)合材料摩擦表面產(chǎn)生的熱應(yīng)力與材料的熱膨脹系數(shù)相關(guān)，材料的熱膨脹系數(shù)越大，產(chǎn)生的熱應(yīng)力越大；過(guò)大的熱應(yīng)力使純樹(shù)脂炭試樣具有相對(duì)穩(wěn)定的摩擦曲線，在較大熱應(yīng)力的作用下，光滑層熱解炭試樣的摩擦曲線不穩(wěn)定，影響其摩擦性能。
關(guān)鍵字: 炭/炭復(fù)合材料；熱膨脹系數(shù)；熱應(yīng)力場(chǎng)；摩擦性能
C/C composites during braking
（State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:The coefficient of thermal expansion (CTE) of three C/C composites with resin carbon matrix, rough lamination pyrocarbon matrix, and smooth lamination pyrocarbon matrix were measured, the finite element analysis software was applied to calculating the stress field of three different C/C composites under the conditions of normal landing energy, and the influence of CTE on the stress field and frictional behavior during braking was studied. The results show that CTE in direction z is larger than that in directions x and y, and CTE becomes larger with the increase of temperature. CTE of the sample with rough lamination pyrocarbon matrix is the smallest, and that of the sample with smooth lamination pyrocarbon matrix is the largest. Correspondingly, the larger the thermal stress, the larger the CTE. Furthermore, large thermal stress makes the sample with resin carbon have a relatively stable friction curve. But the sample with smooth lamination pyrocarbon matrix has unstable friction curve, which influences its frictional behavior.
Key words: C/C composites; thermal expansion coefficient; thermal stress filed; frictional behavior
