(1. 北京航空航天大學(xué) 航空科學(xué)與工程學(xué)院，北京 100191； 2. 沈陽(yáng)飛機(jī)設(shè)計(jì)研究所，沈陽(yáng) 110035)
摘 要: 通過(guò)理論、試驗(yàn)、數(shù)值模擬3種方法研究3D打印鈦合金金字塔型點(diǎn)陣夾芯結(jié)構(gòu)在兩端簡(jiǎn)支三點(diǎn)彎曲載荷下的響應(yīng)，試驗(yàn)中通過(guò)裂紋觀測(cè)儀監(jiān)測(cè)加載過(guò)程。結(jié)果表明：在彎曲載荷下，夾芯結(jié)構(gòu)損傷區(qū)域主要在彎矩最大中線處附近；試件首先在上面板出現(xiàn)塑性變形，隨著第一層桿件的屈曲，載荷迅速下降。通過(guò)掃描電子顯微鏡(SEM)觀測(cè)斷口形貌，驗(yàn)證面板及桿件均為彎曲變形失效。基于ABAQUS軟件，建立結(jié)點(diǎn)剛硬點(diǎn)陣夾芯結(jié)構(gòu)有限元模型，對(duì)結(jié)構(gòu)的漸進(jìn)損傷過(guò)程進(jìn)行預(yù)測(cè)，獲得損傷起始位置、損傷擴(kuò)展、破壞載荷及最終破壞模式等結(jié)果，模擬結(jié)果與試驗(yàn)結(jié)果吻合較好。通過(guò)有限元模型分析寬度方向不同單胞列數(shù)的影響，結(jié)果表明列數(shù)越多，邊界影響越小，結(jié)構(gòu)承載能力越強(qiáng)。
關(guān)鍵字: 點(diǎn)陣夾芯結(jié)構(gòu)；彎曲性能；漸進(jìn)損傷；有限元模擬
（1. School of Aeronautic Sciences and Engineering, Beihang University, Beijing 100191, China; 2.Shenyang Institute of Aircraft Design, Shenyang 110035, China）
Abstract:Response of 3D printing pyramid lattice structure under three-point bending were studied. Progressive damage during the loading process was detected with crack observation instrument. The results reflect that the main damage zone is in the middle of the specimen, where the maximum bending moment is located. The sudden drop of the load occurs with the buckling of the truss. The scanning electron microscope(SEM) is used to observe the fracture morphology which proves that the panels and trusses failed by bending. Finite element model with rigid nodes were established using ABAQUS. Damage location, damage propagation, peak load and failure modes are obtained, which corresponds with the test results. The effects of different unit numbers in width were investigated. It indicates that with more unit cells in width, the effects of the boundary are weakened, resulting in improvement of the load bearing capacity.
Key words: truss core sandwich structure; bending property; progressive damage; finite element simulation
