Elastically-isotropic truss lattice materials of reduced plastic anisotropy

On the thermodynamic requirement of elastic stiffness anisotropy in isotropic materials

In general, thermodynamic admissibility requires isotropic materials develop reversible deformation induced anisotropy (RDIA) in their elastic stiffnesses. Taking the elastic potential for an isotropic material to be a function of the strain invariants, isotropy of the elastic stiffness is possible under distortional loading if and only if the bulk modulus is independent of the strain deviator ...

Hybrid carbon fiber composite lattice truss structures

Lattice truss structures from expanded metal sheet

Metallic lattice truss structures are usually made by perforating a metal sheet with a periodic diamond pattern followed by folding at node rows to create a plate of 3D interconnected trusses. For low relative density lattices, the initial sheet material is inefficiently utilized, and the node area is small raising concerns about node bond robustness under shear or tensile loading. Here, we exp...

Modeling of plastic anisotropy with reduced polycrystalline models. Application to aluminum alloys

Apparent anisotropy in inhomogeneous isotropic media

Surface waves propagating through a laterally inhomogeneous medium undergo wavefield complications such as multiple scattering, wavefront healing, and backward scattering. Unless accounted for accurately, these effects will introduce a systematic isotropic bias in estimates of azimuthal anisotropy. We demonstrate with synthetic experiments that backward scattering near an observing station will...