Mechanical performance of interpenetrating phase composites with multi-sheet lattice structures

Mechanics of ceramic-epoxy interpenetrating phase composites engineered with TPMS and spinodal topologies

Role of build orientation on quasi-static and dynamic fracture responses of additively manufactured AlF357 and AlSi10Mg alloys

Anisotropic Charpy impact behavior of novel interpenetrating phase composites

Hybrid manufacturing and mechanics of copper-based architected materials and copper–aluminum interpenetrating phase composites

IPCs (interpenetrating phase composites) offer a promising approach to enhancing the mechanical properties of orthopedic implants, including strength, fracture toughness, and the potential for incorporating complex functionalities. In this study, Ti6Al4V-PCL IPCs were fabricated by additive manufacturing and infiltrating melted PCL into a Ti6Al4V scaffold with a minimal surface structure. The IPCs introduction modifies the specimen’s failure mode and improves its energy absorption performance through enhanced two-phase interaction and effective stress transfer. Finite element simulations demonstrate increased stress diffusion, improved energy absorption mechanisms, and a prolonged stress plateau period. Among various scaffold types, the Gyroid IPCs exhibit superior mechanical properties, making them an excellent choice for enhancing the performance and functional development of degradable implantable stents.

Hybrid honeycomb structures harness the unique properties of their component cells to achieve superior mechanical performance and energy absorption capacity. This article advances the state of the art by proposing a novel hybrid D2 honeycomb (D2H), which integrates diamond honeycomb (DH) into double-arrow honeycomb (DAH). Its crushing behaviors under quasi-static, low-, and high-velocity are studied. Theoretical models are derived to predict the initial quasi-static collapse stress and high-velocity average stress, based on plastic hinge theory and momentum conservation. Results indicate that the introduction of additional plastic hinges enables D2H to surpass DH and DAH in strength at the same relative density. D2H exhibits significantly enhanced energy absorption compared to DH and DAH. For example, D2H demonstrates approximately 200% higher energy absorption compared to DAH under quasi-static compression. However, the energy absorption enhancement diminishes with increasing crushing velocity, showing 52% and 7% higher energy absorption at 25 m/s and 100 m/s, respectively. Moreover, D2H retains a negative Poisson’s ratio (NPR) effect similar to DAH under both quasi-static and dynamic loading conditions. Effects of design parameters on crushing behaviors are also investigated. For instance, the introduced diamond cell angle allows D2H to maintain a constant stress level during the initial collapse phase while enabling strength adjustments afterward.

Underground structures constitute a vital component in infrastructure development. When subjected to dynamic events, these underground structures will result in catastrophic failures. Hence proper understanding of soil-underground structure interaction is essential when designing in seismic-prone areas. Though analytical models estimate the performance of underground structures under dynamic loading conditions, detailed experimental studies provide more insights into the parameters influencing the underground structure’s performance during dynamic conditions. Due to the limitations in model development, time, and cost, 1-g shaking table experiments were preferred by most of the researchers compared to centrifuge and field scale experiments. This paper presents a detailed literature review of experimental studies on tunnel models in 1-g shaking table experiments and critical observations on tunnel-soil interaction under dynamic loading conditions. Discussions on scaling laws, instrumentation scheme, material selection, and other influencing parameters involved in soil tunnel interaction studies in 1-g shaking table testing conditions are presented. Although the 1-g experimental testing conditions have limitations in simulating equivalent ground and testing conditions as compared to centrifuge studies, this paper highlights the possible steps to simulate the tunnel model interaction studies in a better way to minimize the limitations for upcoming future research works.

Simultaneous high strength and high toughness are highly sought‐after in lattice metamaterials, but these properties are typically mutually exclusive. To overcome this challenge, the development of interpenetrating phase composite (IPC), which incorporates a net matrix infill into the lattice, has shown great potential in overcoming these constraints and is thus of continuous practical interest. In this work, a novel aperiodic monotile truss lattice and polymer IPC that exhibit unprecedented enhancement in both strength and toughness are reported. Specifically, the aperiodic unit cell is inspired by Einstein's monotile, a single space‐filling shape where the cell orientation never repeats. The IPCs are achieved through 3D‐printed Ti‐6Al‐4V truss lattices and epoxy infiltration. The highest gain in compressive strength reveals an impressive 246.61% increase, significantly exceeding the “1 + 1 > 2” idealization typically associated with strength in IPC metamaterials. Furthermore, a high specific energy absorption of 46.2 J g−1 demonstrates superior toughness. The underlying mechanisms, including damage sequences, two‐phase interactions, and geometric effects between truss and epoxy, are fully elucidated. Overall, this work reports unprecedented enhancement in IPC's properties and demonstrates the potential of utilizing idealized structures to achieve an optimal combination of strength and toughness in mechanical metamaterials.

Interpenetrating Phase Composites (IPC) belong to a special category of composite materials, offering great potential in terms of material properties due to the continuous volume structure of both composite components. While manufacturing of metal-ceramic IPC via existing casting and infiltration processes leads to structural deficits, semi-solid forming represents a promising technology for producing IPC components without such defects. Thereby, a solid open pore body made of ceramic is infiltrated with a metallic material in the semi-solid state. Good structural characteristics of the microstructure as the integrity of the open-pore bodies after infiltration and an almost none residual porosity within the composites have already been proven for this manufacturing route within a certain process window. On this basis, the following paper focuses on the mechanical properties such as bending strength of metal-ceramic IPC produced by using semi-solid forming technology. Thereby, the impact of the significant process parameters on these properties is analysed within a suitable process window. Furthermore, a fractographic analysis is carried out by observing and interpreting the fracture behaviour during these tests and the fracture surface thereafter.

Biomimetic Kagome-Gyroid interpenetrating metamaterial for tailoring lightweight and mechanical performance

Numerical and experimental studies on compressive behavior of Gyroid lattice cylindrical shells

Architected cellular structures based on triply periodic minimal surfaces (TPMS) have attracted significant attention due to their lightweight, superior, and controllable mechanical properties. Such lattice structures can be potential candidates for high specific energy absorption (SEA) applications. In this study, five TPMS sheet-based structures (Gyroid, Primitive, IWP, Diamond and Fisher-Koch) were designed, fabricated, and tested under quasi­-static and dynamic loading conditions. Laser powder bed fusion (L-PBF) is employed to facilitate the fabrication of these complex structures using stainless steel (SS316L) at three different relative densities. Scanning electron microscopy (SEM) and micro­ Computed Tomography (micro­CT) were utilized to assess the quality of the printed structures. The dynamic compressive behavior is investigated by conducting direct impact compression tests utilizing a Direct Impact Hopkinson Bar (DIHB) at a strain-rate of 2057 s −1 . Quasi-­static tests are also performed at a strain-rate of 0.005 s −1 . The quasi-static and dynamic mechanical responses are then compared to explore the changes in plateau stress and specific energy absorption values of the five TPMS lattices in these two loading regimes. Furthermore, the effects of changing both architecture and relative density on the properties of lattice structures are investigated. The results show that all five topologies exhibit an enhanced mechanical performance under dynamic loading. In fact, Diamond structure demonstrates the highest SEA value of 35.57 J/g under the high strain-rate loading condition, in comparison to 30.85 J/g in the quasi-static loading. This study suggests that TPMS structures could be potential candidates not only for quasi­-static, but also for dynamic applications related to a high strain-rate loading. • Five TPMS lattices are designed and manufactured using Laser Powder Bed Fusion (LPBF). • Evaluation of the dynamic mechanical performance of lattices based on triply periodic minimal surfaces. • TPMS lattices exhibit enhanced plateau stress and specific energy absorption in high strain-rate loading conditions.

Coal seams, as critical components of open-pit mine slopes, are subjected to both quasi-static and dynamic loading disturbances during mining operations, with their mechanical properties directly influencing the slope stability. Consequently, to clarify the mechanical properties and failure mechanisms of coal seams affected by the strain rate under the static–dynamic loading conditions, the mineral composition and meso-structural characteristics of lignite were analyzed in this study, and uniaxial compression tests with different quasi-static loading rates and dynamic compression tests with different impact velocities were conducted. The results indicate that there is an obvious horizontal bedding structure in lignite, which leads to differences in mechanical response and failure mechanism at different strain rates. Under the quasi-static loading, lignite exhibits significantly lower strain-rate sensitivity than compared to dynamic impact conditions. The Poisson’s ratio difference between the bedding matrix and the lignite will produce interfacial friction, which gradually decreases with the increase in the distance from the interface, thus promoting the transformation of lignite from multi-crack tensile shear mixed fracture to single-crack splitting failure. Under the dynamic impact conditions, low-impact velocities induce stress wave reflection at bedding interfaces due to wave impedance disparity between the matrix and lignite, generating tensile strains that result in bedding-plane delamination failure; at higher velocities, incomplete energy absorption by the rock specimen leads to fragmentation failure of lignite. These findings are of great significance for the stability analysis of open-pit slopes.

Mechanical properties response of isotropic Ti2AlNb/TiAl interpenetrating phase composites with TPMS architectures prepared by laser powder bed fusion

The lightweight characteristics and superior mechanical properties of triply periodic minimal surface (TPMS) structures have attracted widespread attention across various fields, including aerospace, automotive, and medicine. To assess the mechanical performance of TPMS structures, a comparative study was conducted on four typical TPMS structures, including Primitive and Gyroid, using selective laser melting (SLM) and fused deposition modeling (FDM) for fabrication. First, quasi-static compression tests were performed to investigate the mechanical properties of the TPMS structures. Subsequently, the energy absorption characteristics of the four TPMS structures were discussed and analyzed. Finally, a parametric study was conducted to explore the impact of different structural parameters, such as relative density, wall thickness, and parameter C, on the impact resistance of the TPMS structures. The results show that relative density, wall thickness, and parameter C positively influence the energy absorption capacity of the structures and that the energy absorption performance of TPMS structures under low- and moderate-velocity impacts does not differ significantly. This study provides a comprehensive experimental and numerical analysis of four major cell-type TPMS structures, and the findings are of significant importance for the future development and application of TPMS porous structures.