Free-form tensegrities are composed of randomly connected cable and strut elements. The complexity of these structures causes determination of their self-equilibrium form to be a formidable task. There can be an infinite number of solutions with different forms, but it is difficult to identify the best form in terms of stability. Based on the fact that stability of structures is inversely proportional to potential energy, a genetic algorithm minimization process is developed to determine the self-equilibrium form of free-form regular tensegrity structures. The capability of the form-finding process on determination of the most stable form with minimum potential energy is investigated using two main parameters of free-form regular tensegrities which are cable–strut length ratio at rest and number of strut elements. The computational performance of the proposed method is also tested using free-form tensegrities with different number of structural elements.

SLM additive manufacturing has demonstrated great potential for aerospace applications when structural elements of individual design and/or complex shape need to be promptly supplied. 3D-printable AlSi10Mg (RS-300) alloy is widely used for the fabrication of different structures in the aerospace industry. The importance of the evaluation of residual stresses that arise as a result of the 3D-printing process’ complex thermal history is widely discussed in literature, but systematic assessment remains lacking for their magnitude, spatial distribution, and comparative analysis of different evaluation techniques. In this study, we report the results of a systematic study of residual stresses in 3D-printed double tower shaped samples using several approaches: the contour method, blind hole drilling laser speckle interferometry, X-ray diffraction, and Xe pFIB-DIC micro-ring-core milling analysis. We show that a high level of tensile and compressive residual stresses is inherited from SLM 3D-printing and retained for longer than 6 months. The stresses vary (from −80 to +180 MPa) over a significant proportion of the material yield stress (from −⅓ to ¾). All residual stress evaluation techniques considered returned comparable values of residual stresses, regardless of dramatically different dimensional scales, which ranged from millimeters for the contour method, laser speckle interferometry, and XRD down to small fractions of a mm (70 μm) for Xe pFIB-DIC ring-core drilling. The use of residual stress evaluation is discussed in the context of optimizing printing strategies to enhance mechanical performance and long-term durability.

Tensile integrity (tensegrity, tensegric) structures are suggested for possible use in architectural works, bridges, covering large areas, and especially for habitats in outer space and on space bodies because of their minimal need for structural materials and ease of transfer and mounting. Structurally, their behavior is nonlinear and thus their analysis necessitates special care with recourse to special techniques. This study shows that their structural analysis can successfully be performed by a method called total potential optimization using metaheuristic algorithms (TPO/MA) with no special precautions in a very general way. In the applications, which are conducted using software prepared for analyzing all types of nonlinear trusses and trusslike structures, the load-displacement behaviors of tensegric structures are investigated to include also the effect of prestressing level on cables. Genetic algorithms are used in this study as the metaheuristic technique for solving the optimization par...

This paper introduces the OxCM contour method solver, a console application structured based on the legacy version of the FEniCS open-source computing platform for solving partial differential equations (PDEs) using the finite element method (FEM). The solver provides a standardized approach to solving linear elastic numerical models, calculating residual stresses corresponding to measured displacements resulting from changes in the boundary conditions after minimally disturbing (non-contact) cutting. This is achieved through a single-line command, specifically in the case of availability of a domain composed of a tetrahedral mesh and experimentally collected and processed profilometry data. The solver is structured according to a static boundary condition rule, allowing it to rely solely on the cross-section occupied by the experimental data, independent of the geometric irregularities of the investigated body. This approach eliminates the need to create realistic finite element domains for complex-shaped, discontinuous processing bodies. While the contour method provides highly accurate quantification of residual stresses in parts with continuously processed properties, real scenarios often involve parts subjected to discontinuous processing and geometric irregularities. The solver’s validation is performed through numerical experiments representing both continuous and discontinuous processing conditions in artificially created domains with regular and irregular geometric features based on the eigenstrain theory. Numerical experiments, free from experimental errors, contribute to a novel understanding of the contour method's capabilities in reconstructing residual stresses in such bodies through a detailed error analysis. Furthermore, the application of the OxCM contour method solver in a real-case scenario involving a nickel-based superalloy finite-length weldment is demonstrated. The results exhibit the expected distribution of the longitudinal component of residual stresses along the long-transverse direction, consistent with the solution of a commercial solver that was validated by neutron diffraction strain scanning.

Residual stresses play a critical role in the performance and reliability of additively manufactured components, particularly in geometrically complex structures fabricated using selective laser melting (SLM). Bridge-like structures, in particular, experience significant residual stress concentrations due to localized heat accumulation and constrained thermal expansion. This study presents a novel application of the OxCM contour method solver for high-resolution planar mapping of residual stress distribution in an additively manufactured Inconel 718 bridge structure with 12 legs of varying sizes. By employing optimized data smoothing techniques and leveraging Saint–Venant’s principle, this work enhances the accuracy of stress reconstruction while ensuring physical consistency. The results reveal tensile stresses along the edges and compressive stresses concentrated in the central region, with local variations influenced by bridge-like features. This study contributes to the field by providing critical insights into the interplay between geometry and residual stress in SLM components and demonstrating the effectiveness of the contour method for detailed stress characterization. The findings offer a foundation for optimizing process parameters and structural designs to improve the reliability and performance of additively manufactured parts in aerospace, automotive, and energy applications.