Open porous lattice structures have found a wide range of applications as lightweight load‐bearing and energy absorbent structures in various fields. A common requirement for any application is the preliminary assessment of the mechanical response of the proposed architecture. Herein, uniform and continuous functionally graded lattice structures (FGLSs) made of titanium alloy, Ti–6Al–4V, are designed using cubic and pillar octahedron unit cells at overall porosities of 60%, 75%, and 85%. The lattice morphology is modulated using axial, dense‐in, and dense‐out gradient strategies. The mechanical performance of the structures is studied using numerical simulations implementing damage initiation and evolution under quasi‐static compression. The proposed models could properly simulate the mechanical properties and failure behavior of the lattice structures. The designed FGLSs displays a crushing behavior starting from the lower relative density layers toward the higher relative density ones. Cubic and pillar octahedron‐based structures exhibit stretch‐ and bending‐dominated deformation behaviors, respectively. The power‐law analysis verified by the Gibson–Ashby model is used to assess the mechanical response of the FGLSs. The effect of the gradient strategies on the mechanical properties as well as their adaptability for orthopedic implants is discussed in detail.
1 January 2015 in Transactions of Nonferrous Metals Society of China
Impact surface treatments are well-known for their efficiency in enhancing the mechanical properties of metallic materials, especially under cyclic loadings. These processes, which encompass a wide range of surface treatments based on repetitive impacts of tools of various types, induce surface plastic deformation, compressive residual stresses, and grain refinement alter the surface roughness as a side effect. Thus, it is essential to have suitable indexes to quantify the surface features caused by the typically random nature of these treatments. Herein, we evaluated the rationality of using standard roughness parameters for describing the morphological characteristics of surfaces treated by shot peening as a representative and widely used treatment of the category. A detailed numerical model of the peening process was developed. The output data were elaborated to extract the surface roughness parameters following the standard procedures. The results revealed the validity of the surface roughness parameters to describe the topography of material treated with adequate surface coverage, also highlighting the necessity to use a set of parameters rather than the common practice of relying on single parameters. Not considering a comprehensive set of amplitude and spacing parameters can result in significant, inconsistent, and misleading results while comparing the performance of surfaces.
28 August 2024 in Applied Surface Science Advances