Structural Design and Dynamic Compressive Properties of Ti–6Al–4V Hollow Lattice Structures

Abstract

Herein, three groups of Ti–6Al–4V hollow lattice structures with different strengthening structures are designed and manufactured using a selective laser melting method. A basic structure (specimen BS), a basic structure with strengthening structures at joints (specimen SJ), and a basic structure with a strengthening structure on tube walls (specimen SW) are compressed by a split Hopkinson pressure bar system. The potential influence of strengthening structures and strain rates on dynamic compressive properties is investigated. The results indicate that the strengthening structures change the structural weaknesses and stress concentration regions inside the basic structures; thus, specimens BS and SJ collapse on the struts, whereas specimen SW breaks at the joints. The strengthening structures of specimen SJ reinforce the nonstructural weaknesses inside the basic structure, resulting in the mechanical properties showing limited improvement or even decrease. However, the strengthening structures of specimen SW strengthen the structural weaknesses inside the basic structure, so the collapse strength, specific collapse strength, energy absorption (EA), and specific EA (SEA) of specimen SW, respectively, increase by 46.1%, 8.4%, 42.0%, and 6.5%, which shows that specimen SW exhibits excellent mechanical properties. Moreover, strain rate sensitivity of specimen SW is dominated by the strain rate effect of Ti–6Al–4V material.

Spatial Array Configuration Effect of Body‐Centered Cubic Lattice Structures with Finite Unit Cells

“…Figure 7c shows the equivalent modulus of 3-layer structures with increasing cells in the x-direction. The red circle donates the analytical results from Equation (7), which shows the same trend as the FEM results in the blue square. Both the analytical and FEM results show that the equivalent modulus varies greatly with the spatial array parameters (n x and n z ), and will converge to the Ashby model [18] with the increasing number n x .…”

“…This leads to a search for microstructures that deform by the stretching/compression of constituent cell walls, giving a much higher stiffness and strength per unit mass. [ 5–8 ]…”

“…This leads to a search for microstructures that deform by the stretching/compression of constituent cell walls, giving a much higher stiffness and strength per unit mass. [5][6][7][8] Periodic lattice structures have been studied extensively in engineering applications, because they can offer superior performance such as high stiffness-to-weight and excellent energy absorption than foam structures comprised of plates. [9][10][11][12] A number of previous studies have investigated the mechanical properties of octet, [13] diamond, [14] BCC, [15] and pyramidal [16] lattice structures using theoretical, numerical, and experimental techniques during the past decades.…”

An Experimental and Computational Modeling Study on Additively Manufactured Micro‐Architectured Ti–24Nb–4Zr–8Sn Hollow‐Strut Lattice Structures

“…The present literature is dominated by studies on the feasibility of manufacturing hollow-strut lattice structures. [17,28,[37][38][39][40][41] There are very few studies on the mechanical properties of hollowstrut lattice structures. [37] A previous study on hollow triply periodic minimal surface (TPMS) lattices studied the addition of different tubular-strengthening structures at different positions of TPMS.…”

Enhanced Cellular Materials through Multiscale, Variable-Section Inner Designs: Mechanical Attributes and Neural Network Modeling

“…While it is currently well-established that the insertion of inner-material scales beyond the primal cellular pattern provides additional degrees of freedom for design, the corresponding material spaces remain, to a great extent, unexplored. Existing contributions have mainly emphasized on hollow inner designs [ 60 , 61 ], with the form of their inner structural components remaining unchanged. In particular, multiscale cellular metamaterials with hollow, variable-section inner designs have not been yet analyzed, their macroscale material performance remaining unquantified, both numerically and experimentally.…”