•AM techniques for fabricating composite lattices are reviewed.•Characteristics of different classes of lattice architectures are reviewed.•AM composite lattices are classified in terms of AM methods ...and reinforcements.•Mechanical properties of AM composite lattices are discussed.•Future directions considering AM process and structural optimization are discussed.
Finding ideal materials remains a crucial challenge in the aerospace, automotive, construction, and biomedical industries. Moreover, a growing concern about environmental burden and fuel consumption has triggered strong demand for lightweight materials with high-performance multifunctional characteristics. Composite lattices exploiting topological and constituent materials are of particular interest thanks to their excellent mechanical properties and lightweight that can ideally meet critical design requirements. However, composite lattices are integrated with high complexity in their geometries, which creates challenges in their manufacturing in practice. Additive manufacturing (AM) technologies have been extensively developing to provide more freedom in manufacturing to support the growing interest in fabricating these innovative materials with intricate geometry. This paper reviews current studies on additively manufactured composite lattices. First, AM and post-treatment techniques and their capability for fabricating complex structural materials are discussed. Then, several types of structural configurations and characteristics of AM composite lattices are reviewed. Further, the mechanical properties of these composite lattices are analyzed and the role of reinforcing phases is discussed in detail. Finally, the review highlights some potential future research directions and opportunities of 3D printed composite lattices for energy absorption, recoverability, specific strength and stiffness, and weight lightening.
Strut-based lattice structures (SLSs) have been widely used in modern industries including aerospace, automobile and biological implant, due to their unique properties such as lightweight, good ...energy absorption capability and high specific strength. However, the obtainable mechanical performance is significantly limited by the monotonous strut-based feature without any reinforcement topology. The inherent strengthening mechanisms and atom-scale models in material science may be crucial and valuable to optimize the complex structures with desired properties. Inspired by the solid solution strengthening mechanisms in crystal microstructure, a series of novel crystal-inspired hybrid structures, i.e., the common face-center cubic with Z-strut (FCCZ) structure, the face-center substitutional lattice (FCSL) structure, the edge-center interstitial lattice (ECIL) structure and the vertex-node substitutional lattice (VNSL) structure were designed and fabricated by laser powder bed fusion (LPBF) additive manufacturing in this work. The effect of node location on the LPBF formability, mechanical performance, stress distribution, deformation modes and failure mechanisms of the crystal-inspired components was systematically investigated. The computational fluid dynamics (CFD) method was used to understand the dynamics of molten pool to reveal the formation mechanism and control methods of the dross defect attached to overhanging surfaces. Finite element model (FEM) was established to show the stress distribution and deformation behavior of these hybrid structures during compression. Results showed that the ECIL structure possessed the highest specific energy absorption (SEA) of 13.7 J/g, which increased by 17% compared with the initial FCCZ structure. The crush force efficiency (CFE) of VNSL structure reached the peak value of 66% with a unique axisymmetric shear band during deformation, which increased by 14% compared to the FCCZ structure. The underlying mechanism analysis revealed that the as-designed spherical node could redistribute the stress and the performance of the lattice structures could be manipulated by tailoring the position of the spherical nodes. The present approach suggested that the hardening principles of crystalline materials could inspire the design of novel lattice structures with desired properties.
•Hybrid lattice structures inspired by crystal microstructure are designed and fabricated.•Dross formation mechanism induced by suspension condition is investigated.•High specific energy absorption (13.7J/g) and crush force efficiency of 66% are obtained.•Strengthening mechanism at micro scale is also applicable to enhancement of macro lattice structure.
40 years ago, Conway and Sloane proposed using the highly symmetrical Coxeter-Todd lattice K 12 for quantization, and estimated its second moment. Since then, all published lists identify K 12 as the ...best 12-dimensional lattice quantizer. Surprisingly, K 12 is not optimal: we construct two new 12-dimensional lattices with lower normalized second moments. The new lattices are obtained by gluing together products of two 6-dimensional lattices.
Lattice Boltzmann method (LBM) is a relatively new simulation technique for the modeling of complex fluid systems and has attracted interest from researchers in computational physics. Unlike the ...traditional CFD methods, which solve the conservation equations of macroscopic properties (i.e., mass, momentum, and energy) numerically, LBM models the fluid consisting of fictive particles, and such particles perform consecutive propagation and collision processes over a discrete lattice mesh. This book will cover the fundamental and practical application of LBM. The first part of the book consists of three chapters starting form the theory of LBM, basic models, initial and boundary conditions, theoretical analysis, to improved models. The second part of the book consists of six chapters, address applications of LBM in various aspects of computational fluid dynamic engineering, covering areas, such as thermo-hydrodynamics, compressible flows, multicomponent/multiphase flows, microscale flows, flows in porous media, turbulent flows, and suspensions.
Analytical and numerical analyses for predicting the mechanical responses of BCC and FCC lattice structures under compressive loading were performed and verified by comparing them to experimental ...data. The analytical and numerical results are in excellent correlation, while the error between the experimental and numerical results is about 5.8 ~ 15.3 %, which was caused by the inconsistent lattice strut diameter and the material elastic modulus. The measured lattice strut diameter is smaller than the designed diameter by thermal shrinkage, so the thermal shrinkage should be taken into the lattice structure design in additive manufacturing processes. Based on the same analytical and numerical techniques, a parametric investigation of the elastic moduli of BCC and FCC lattice unit cells with respect to the strut aspect ratio, specific density and strut angle was performed. Finally, the elastic moduli of multi-cell BCC and FCC lattice structures with the same density were investigated by varying the number of rows and columns of lattice unit cells in both unconstrained and constrained boundary conditions. As the strut aspect ratio, density and angle increase, the elastic moduli of both BCC and FCC lattice increase. FCC elastic modulus is higher than that of BCC lattice with respect to the strut aspect ratio, density and angle, while BCC elastic modulus could be found to be higher than of FCC lattice for a constrained boundary condition.
Charmed tetraquarks Tcc=(ccu¯d¯) and Tcs=(csu¯d¯) are studied through the S-wave meson–meson interactions, D–D, K¯–D, D–D⁎ and K¯–D⁎, on the basis of the (2+1)-flavor lattice QCD simulations with the ...pion mass mπ≃410, 570 and 700 MeV. For the charm quark, the relativistic heavy quark action is employed to treat its dynamics on the lattice. Using the HAL QCD method, we extract the S-wave potentials in lattice QCD simulations, from which the meson–meson scattering phase shifts are calculated. The phase shifts in the isospin triplet (I=1) channels indicate repulsive interactions, while those in the I=0 channels suggest attraction, growing as mπ decreases. This is particularly prominent in the Tcc(JP=1+,I=0) channel, though neither bound state nor resonance are found in the range mπ=410–700 MeV. We make a qualitative comparison of our results with the phenomenological diquark picture.
Prior analytical and numerical studies have shown that the triangular lattice is one of the stiffest, strongest and toughest geometries of 2D lattices. However, there has been little previously ...published experimental data on mechanical properties of triangular lattices. In this work the modulus, tensile strength and fracture toughness of 2D triangular lattices have been measured experimentally. The accuracy of existing prediction methods for lattice properties has been evaluated. The dependence of strength and toughness on the orientation of the lattice has also been measured. It has found that the tensile strength and fracture behaviour vary markedly with orientation, although the lattice modulus is isotropic. The measured results agree well with analytical and FE predictions.
We study the dynamics and timescales of a periodically driven Fermi-Hubbard model in a three-dimensional hexagonal lattice. The evolution of the Floquet many-body state is analyzed by comparing it to ...an equivalent implementation in undriven systems. The dynamics of double occupancies for the near- and off-resonant driving regime indicate that the effective Hamiltonian picture is valid for several orders of magnitude in modulation time. Furthermore, we show that driving a hexagonal lattice compared to a simple cubic lattice allows us to modulate the system up to 1 s, corresponding to hundreds of tunneling times, with only minor atom loss. Here, driving at a frequency close to the interaction energy does not introduce resonant features to the atom loss.
40 years ago, Conway and Sloane proposed using the highly symmetrical Coxeter–Todd lattice K 12 for quantization, and estimated its second moment. Since then, all published lists identify K 12 as the ...best 12-dimensional lattice quantizer. Surprisingly, K 12 is not optimal: we construct two new 12-dimensional lattices with lower normalized second moments. The new lattices are obtained by gluing together products of two 6-dimensional lattices.
PDF
