The reliable experimental characterization of architected lattice materials under cyclic loading requires accurate fixture systems that ensure proper load transfer without introducing parasitic effects. This study presents the design and validation of testing fixtures optimized using density-based topological optimization techniques for performing cyclic load tests on lattice structures. The supports were manufactured with PLA filaments and evaluated using finite element simulation and experimental testing. The results show that the final design achieved a safety factor of 4.25, significantly improving on the initial value of 2.08. Likewise, the optimized supports showed reduced deformations by around 80% compared to the machine clamps, ensuring rigid and reliable stress transfer. In particular, while the metal structure of the test system showed deformations of several millimeters, the optimized PLA supports recorded displacements around 0.73 mm, confirming that they remain virtually rigid and ensure correct transmission of forces to the Kelvin-type structure. These findings confirm the viability of using PLA as an alternative to conventional metal devices in fixtures for mechanical testing of lattice materials.

This study addresses the challenges associated with conventional plywood shear testing by introducing a novel miniaturized shear test method. This approach utilizes a controlled router toolpath for precise sample fabrication, enabling efficient material use and data acquisition. Miniaturized samples, designed with double shear zones, were tested for τ_xy, τ_xz, and τ_yz configurations using a universal testing machine. Results revealed a mean ultimate shear strength ranging from 5.6 MPa to 7.3 MPa and a mean shear modulus ranging from 0.039 GPa to 0.095 GPa, confirming the orthotropic nature of plywood. The resulting shear behavior was determined with stress–strain curves correlated with failure patterns. The miniaturized tests effectively captured the material’s heterogeneous behavior, particularly at smaller scales, and demonstrated consistent load-bearing capacity even after substantial stress reduction, suggesting suitability for bracing applications. This method allows for increased sample sizes, facilitating robust data collection for developing and validating finite element models. Future work will focus on evaluating the scalability of the observed orthotropic behavior and data scatter at larger scales and assessing the potential for this method to replace conventional full-scale plywood shear testing.

The construction sector’s environmental footprint is driving the adoption of sustainable modular timber systems. The WikiHouse Skylark is a promising open-source model whose structural reliability depends on the performance of its critical plywood TIE joints. This study presents an experimental investigation of full-scale TIE joints fabricated from 18 mm Pinus radiata plywood in three variants: Standard (STD), Weather-Resistant (HR), and Fire-Resistant (FR). Monotonic tensile and shear tests were conducted to evaluate load–displacement behavior and failure modes. While the mean ultimate strengths varied between panel types, with HR highest in tension (7.7 kN) and FR highest in shear (8.2 kN), the most critical finding was the effect of the treatments on failure mode. The FR treatment induced a brittle fracture with significantly reduced ductility, in contrast to the more ductile tearing observed in STD and HR panels. This highlights a clear strength–ductility trade-off introduced by the fire-retardant treatment, a key consideration for structural design in modular timber construction. This dataset provides an essential empirical foundation for the numerical modeling and design guidelines of WikiHouse TIE joints, advancing the development of resilient and sustainable prefabricated housing.

Background: Radiotherapy technology has undergone significant advancements, driven by the pursuit of improved tumor control probabilities and reduced normal tissue complication probabilities. This has been achieved primarily through innovative approaches that prioritize high dose conformity on complex treatment targets. The CONVERAY project introduces a groundbreaking teletherapy system featuring a convergent X-ray beam, which enables highly conformal dose distributions by converging photons to a focal spot, thereby achieving exceptionally high fluence rates. Methods: Customized Monte Carlo subroutines have been developed to simulate particle fluence and associated dosimetry effects for the CONVERAY device. This simulation approach facilitated a detailed, step-by-step characterization of radiation fluence and interaction processes, enabling seamless integration with a conventional clinical linear accelerator head. Key physical properties of the radiation beam have been comprehensively characterized for various CONVERAY configurations, providing a solid foundation for evaluating the corresponding dosimetry performance. Results: Monte Carlo simulations successfully tracked the phase state of the CONVERAY device, characterizing the influence of individual components on convergent photon beam production. Simulations evaluated dosimetry performance, confirming the device’s capability to achieve high dose concentrations around the focal spot. Preliminary tests on realistic scenarios (intracranial and pulmonary irradiations) demonstrated promising spatial dose concentration within tumor volumes, while gantry rotation significantly improved dose conformation. Conclusions: This proof-of-concept Monte Carlo study of the CONVERAY prototype provided critical insights into the generation of convergent X-ray beams, validating the device’s ability to achieve its primary objective. Notably, simulation results reveal the potential for exceptionally high dose concentrations within complex treatment volumes, demonstrating promising dosimetry performance.

Integral CNC-machined timber connections provide an efficient fastening-free solution for digitally fabricated modular construction systems. Their response under repeated loading is governed by the interaction between joint geometry, plywood architecture, contact, and progressive material damage. This study experimentally investigates the quasi-static cyclic response of full-scale TIE joints used in the WikiHouse Skylark system and manufactured from 18 mm Pinus radiata D. Don plywood. Three plywood configurations were evaluated: standard structural plywood (STD), weather-resistant plywood (HR), and fire-resistant plywood (FR), with the central TIE element oriented either parallel (//) or perpendicular (⊥) to the applied load. A displacement-controlled cyclic protocol adapted from ISO 16670 was applied. The exploratory cyclic program used one full-scale specimen per tested configuration ($n=1$), comprising six tensile configurations and three shear configurations. Tensile joints were subjected to one-sided loading–unloading cycles, whereas shear joints were subjected to reversed cyclic displacement. Under cyclic tension, maximum forces ranged from 6.082 to 9.794 kN at displacements between 6.6 and 10.3 mm, with the highest measured force obtained for the HR ⊥ configuration. Reversed cyclic shear tests produced maximum forces between 8.212 and 8.976 kN at displacements between 4.7 and 7.0 mm. Across all tested configurations, the apparent initial stiffness ($K_e$) ranged from 1.202 to 1.641 kN/mm, while the cumulative dissipated energy ($E_d$) ranged from 105.02 to 425.81 J. Damage consistently localized within or adjacent to the reduced central TIE region and involved combinations of tensile cracking, shear fracture, local crushing, fiber separation, and fiber rearrangement. The results show that the integral TIE geometry maintains a well-defined load-transfer and failure region under progressively increasing cyclic displacement. The experimental evidence provides a component-level basis for subsequent replicated testing and the development of nonlinear models of digitally fabricated plywood connections.