Study on bucking and post-buckling behavior of vertical latticed structures

2022 Fiscal Year Final Research Report

• Project/Area Number: 18K04440
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 23010:Building structures and materials-related
• Research Institution: Kogakuin University
• Principal Investigator: Yamashita Tetsuo 工学院大学, 建築学部(公私立大学の部局等), 教授 (80458992)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Keywords: 円筒ラチスシェル / 塑性座屈 / 変形性能 / 線形座屈解析 / ３Dプリンター / 形状初期不整 / アルミ / ステンレス

Outline of Final Research Achievements

Plastic buckling strength and ductility in the post-buckling behavior of axially loaded metal latticed cylinderical tubes, were investigated through experimental and analytical studies. Nonlinear FE analysis was verified by comparing with the test results. In the experimental study, 3D-printed latticed cylinders made of aluminum alloy and stainless steel were fabricated. A novel methodology for extracting a skeletal model and specifying geometric imperfection from the 3D-scanned data of the test bodies, was developed.
The latticed cylinders were composed of two kinds of grid, triangular and hexagonal in which axial force and bending were dominant, respectively. It was found that the classical tangent modulus theory is effective to estimate plastic buckling strength regardless the dominant stress, and the ductility factor can be roughly approximated by function proportional to the reciprocal of the square of the generalized slenderness, determined by linear buckling and yield loads.

Free Research Field

建築構造

Academic Significance and Societal Importance of the Research Achievements

近年縦型単層ラチス構造が重層構造の柱や外周あるいは塔状構造物に使用されている。縦型の場合は支持する荷重が大きいため部材が太く塑性座屈を生じ座屈後の靭性も必要である。本研究は実験と解析の両面より軸圧縮を受ける円筒ラチスシェル構造の塑性座屈耐力と座屈後変形性能を評価し、簡単な線形座屈解析と塑性解析で軸圧縮塑性座屈荷重と塑性変形性能が推定可能なことを示した。試験体はアルミとステンレスを材料として３Ｄプリンターで製作し、３Ｄスキャンデータより初期不整を含んだ骨組モデルを抽出する方法を開発した。これにより以降金属製ラチスシェル構造の弾塑性座屈実験が安価に実行でき、この分野の実証的研究に寄与する。