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Mechanical behavior of lattice structures is important for a range of engineering applications. Herein, a new semiempirical model is proposed that describes the entire range of stress–strain response of lattice structures, including the stress‐instability region which is modeled as an oscillator. The model can be fit to individual stress–strain curves to extract elastic modulus, yield stress, collapse stress, post‐yield collapse ratio, densification strain, and the energy absorbed per unit volume. The model is fit to 119 unique experimental stress–strain curves from 13 research papers in literature covering four different lattice designs, namely, octet truss, body‐centered cubic with vertical members, body‐centered cubic, and hexagonal. Manufacturing methods (additive and conventional) and materials (metals and polymers) were also included in the analysis. The fitted model yields several new insights into the compression behavior of previously tested lattice structures and can be applied to additional lattice designs. Among other results, analysis of variance (ANOVA) reveals that the octet truss lattice demonstrates the highest post‐yield collapse ratio and the smallest normalized energy absorption per unit volume amongst the lattice structures investigated. The proposed model is a powerful tool for designers to quantitatively compare and select 3D lattice structures with the desired mechanical characteristics.

Nanoparticle 3D printing and sintering is a promising method to achieve freeform interconnects on compliant substrates for applications such as soft robotics and wearable healthcare devices. However, previous strategies to sinter metallic nanoparticles while preserving the soft polymer substrate are rife with problems such as cracking and low conductivity of the metallic features. In this paper, the mechanisms of cracking in nanoparticle‐based 3D printed and sintered stretchable interconnects are identified and architecture and processing strategies are demonstrated to achieve crack‐free interconnects fully embedded in thin (<100 μm in thickness) stretchable polydimethylsiloxane (PDMS) with external connectivity. Capillary forces between nanoparticles developed through rapid solvent evaporation in the colloidal ink is hypothesized to initiate cracking during drying. Additionally, the presence of oxygen promotes the removal of organic surfactants and binders in the nanoparticle ink which increases nanoparticle agglomeration, grain growth, and subsequently conductivity. An experimental step‐wise variation of the thermal/atmospheric process conditions supports this hypothesis and shows that the presence of air during a low temperature drying step reduces the capillary stress to produce crack‐free interconnects with high conductivities (up to 56% of bulk metal) while having an excellent compatibility with the underlying polymer materials. Finally, stretchable interconnects fully‐encapsulated in PDMS polymer, with 3D pillar architectures for external connectivity are demonstrated, thus also solving an important “last‐mile” problem in the packaging of stretchable electronics.