Elastic properties of metallic materials made by additive manufacturing

2018 Fiscal Year Final Research Report

• Project/Area Number: 16H04236
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Materials/Mechanics of materials
• Research Institution: Osaka University
• Principal Investigator: Tarumi Ryuichi 大阪大学, 基礎工学研究科, 教授 (30362643)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 金属積層構造体 / ラティス構造 / 超音波共鳴法 / 有限要素法 / 弾性定数 / Micropolar弾性理論 / ひずみ勾配弾性理論 / サイズ効果

Outline of Final Research Achievements

We developed a new experimental method which determines the elastic properties of three-dimensional metallic materials made by additive manufacturing (AM) technique. Our method is based on the resonant ultrasound spectroscopy (RUS) and finite element method (FEM). Three-dimensional lattice structures are prepared by selective laser melting for metallic powder. Ultrasound experiment is conducted using tripod-type RUS measurement system and which revealed that the resonance frequencies of the lattice structures can be measured with sufficient accuracy. We also conducted FEM calculation for inverse analysis of the resonance frequencies. Present analysis demonstrates that we can evaluate elastic properties of the lattice structures by combining the RUS experiment and FEM analysis. In addition to the experimental studies, we also conducted theoretical study based on Micropolar elasticity and strain gradient elasticity focusing on the size dependence of resonance frequency.

Free Research Field

固体力学

Academic Significance and Societal Importance of the Research Achievements

AM技術を用いて作成された金属構造体は，テーラーメード医療材料や宇宙・航空機材料など，高付加価値を持つ高比強度材料としての応用が期待されているが，その実用化を進めるためには弾性特性の直接評価が不可欠である．本研究で新たに開発した計測システムを用いれば，原理的には任意の外形・内部構造を持つ金属構造体の弾性特性評価に応用できるという特徴を持っている．また，本研究で解析を進めた二つの弾性理論（Micropolar弾性理論とひずみ勾配弾性理論）は，ラティス構造を持つ金属構造体の力学特性解析に適しており，将来的には理論基盤としての応用が期待される．