Controlling and testing anisotropy in additively manufactured stochastic structures
Controlling and testing anisotropy in additively manufactured stochastic structures
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DOI：
10.1016/j.addma.2021.101849
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发表时间：
2021-03-01
影响因子：
11
通讯作者：
Jeffers, Jonathan R. T.
中科院分区：
文献类型：
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作者：
Hossain, Umar;Ghouse, Shaaz;Jeffers, Jonathan R. T.
增材制造（AM）可以对多孔晶格结构的结构和机械性能进行精细控制。用于多孔结构的典型周期单元胞本身具有各向异性，可能不适合多轴应用，并且不能可靠地创建低构建角度的特征或支柱。本研究使用激光粉末床熔合（PBF）在不锈钢（SS316L）和钛合金（Ti6Al4V）中制造各向同性随机多孔结构，并进行了修改，旨在克服PBF制造的构建角度限制。结构在相对于结构的10个载荷方向（n = 5）下进行单轴压缩测试，包括三个正交轴。试验验证了随机结构中不存在弹性模量的隐峰。对结构的修改使10个弹性模量值的标准差从SS316L的249 MPa降低到101 MPa， Ti6Al4V的95.9 MPa降低到52.5 MPa，表明结构更加各向同性。这些改进的随机结构改善了刚度各向同性，可用于轻量化和生物材料应用，减少了性能对构建方向的依赖，并允许构建平台上组件方向的更大灵活性。
Additive manufacturing (AM) enables fine control over the architecture and mechanical properties of porous lattice structures. Typical periodic unit cells used in porous structures are inherently anisotropic, may not be suitable for multi-axial applications and cannot reliably create features or struts with low build angle. This study used laser powder bed fusion (PBF) to create isotropic stochastic porous structures in stainless steel (SS316L) and titanium alloy (Ti6Al4V), with modifications that aimed to overcome PBF manufacturing limitations of build angles. The structures were tested in uniaxial compression (n = 5) in 10 load orientations relative to the structure, including the three orthogonal axes. The testing verified that no hidden peaks in elastic modulus existed in the stochastic structure. Modification to the structure reduced the standard deviation of the 10 elastic modulus values from 249 MPa to 101 MPa when made in SS316L and from 95.9 MPa to 52.5 MPa for Ti6Al4V, indicating the structures were more isotropic. These modified stochastic structures have improved stiffness isotropy and could be used for lightweighting and biomaterial applications, reducing the dependence of performance on build orientation, and allowing more flexibility for component orientation on the build platform.