This paper investigates experimentally and numerically the influence of geometry and loading conditions on the fracture response of rock materials. Seven different test samples namely “Edge-Notched-Disc-Bend (ENDB), Semi-Circular-Bend (SCB), Three-Point-Bend-Inclined-Crack (TPB-IC), Single-Edge-Notched-Bending (SENB), Asymmetric-Three-Point-Bend (ATPB), Edge-Notched-Disc-Compression (ENDC) and Double-Notched-Disc-Compression (DNDC)” made of a marble rock were manufactured and tested under bending and compressive loading conditions. The results showed that the failure loads of all samples increase with the change of pure mode I to pure mode III. However, the corresponding fracture toughness values of ENDB, SCB, TPB-IC, SENB and ATPB specimens decreased, while the ENDC and DNDC samples experienced an increase in the fracture toughness. Among the studied specimens, only the ENDB, ENDC and DNDC samples presented pure mode III with KIIIc/KIc ratio ranging from 0.735 for the ENDB specimen to 2.076 for the DNDC sample. The highest mode-I fracture toughness among all the studied specimens was obtained for the SENB and TPB-IC samples, with a value of 1.54 MPa m0.5, while the lowest value was obtained for the DNDC specimen with a value of 1.21 MPa m0.5. The sign and the magnitude of T-stress considerably depended on the loading condition and geometry of the specimens. The crack trajectories of all specimens under study were also investigated.

The article assesses the structural strength of sample materials destroyed on standard equipment for determining the mechanical properties of materials. The distribution of mechanical stresses of laboratory disk samples with stress concentrators in the form of grooves on the support surfaces was analyzed. It was revealed that the disc truncation along the two symmetrical chords allows for varying the type of stress state in the sample and intensity of stresses in the working zone. The problems of the linear theory of elasticity were solved for samples with different degrees of disc truncation and with different geometric parameters of the groove profile. The analysis of disk deformation showed that these laboratory samples can be used in simulating the type and level of stress-strain state of various parts of machines and mechanisms. This factor significantly expands the possibilities for assessing the structural strength of materials during laboratory studies of the materials. It was revealed that the type of stress-strain state (SSS) plays a role in localizing the sources of destruction of highly loaded structural elements made from structural carbon steel St45. The results can be used both for the experimental assessment of the structural strength of materials and for constructing limit state equations corresponding to a SSS level and type.

Retraction: The editors of Engineering Solid Mechanics retract this article [1] due to severe plagiarism.

In this article, mathematical modelling of torsional vibrations of a truncated circular conical shell located in an elastic medium is carried out. It is believed that the shell is exposed to external dynamic loads, and its material is homogeneous and isotropic. Based on the exact mathematical formulation of the problem, general equations of nonstationary torsional vibrations of a truncated conical shells have been developed, from which, in particular cases, the equations of vibration of a truncated conical rod, as well as a circular cylindrical shell and a round rod follow. The desired functions found by solving the vibrational equations are used to construct a method for computing the stress-strain state of any point in the system under investigation. As an example.

This study investigates the generalized stiffness of laterally functionally graded materials (LFGMs) and applies these findings to dynamic beam elements. The generalized stiffnesses of LFGM, coupled with material and cross-sectional properties such as flexural and axial rigidity, mass per unit length, and mass-moment of inertia, are explicitly formulated. In the context of LFGM, material properties depend on an asymmetrical power law function with respect to cross-sectional depth. An example of the generalized numerical stiffness of a circular cross-section is provided for various material properties. To illustrate the application of generalized stiffness to dynamic beam elements, free vibration of LFGM beams with rotary inertia is considered. The dimensionless differential equation governing the free vibration of such beams is derived and numerically solved to obtain natural frequencies and corresponding mode shapes. Numerical results demonstrate a good consistency with the finite element method.

This paper reviews context and results of a software tool, named SaTrade, for Model Based System Engineering in System Design of a CubeSat. This tool helps designers to go through system design trade offs easily in System and Subsystem Levels. To achieve this, Modeling for subsystem design has been made using Block Diagram Definitions and implemented in codes with Inputs from System Design and Outputs to Subsystem specifications and Design Integration. Another Feature of SaTrade is change and modification control and management, where it can be from Requirements or other Inputs from System Design or Interfaces. Changes will be affected on the System Design to allow the Designers follow the process by simulations for Integrity check and Evaluation. The first version of SaTrade focuses on Satellite Structure Design and Configuration Management more, using its Neural Network Algorithms dedicated for this purpose, however, it is intended to make paperless automated design available for the whole CubeSat System in the next version.

Additive Manufacturing (AM) is becoming the leading innovation in many fields due to its ease in generating a 3D object by adding one layer of material over the other from a source of Computer Aided Design (CAD) model as input file. Fused Deposition Modeling (FDM) is one among the technologies available in AM, which works on material extrusion process for which the material is served in filament shape. The practice of utilizing the resources effectively by meeting the requirements of subsequent generations is internationally referred to as Sustainable Manufacturing (SM). It deals with the issues that impact the economy, society and environment. Green manufacturing approaches like reduce, reuse and recycle theories are linked with 3D Printing. In this paper research has been conducted on the studies of sustainability of the parts produced on FDM for ASTM D638 Type- IV standard tensile test specimen to optimize the process parameters for Acrylonitrile Butadiene Styrene (ABS) material by using Design of Experiments (DOE) through Taguchi technique and Analysis of Variance (ANOVA). The variables considered are print speed, orientation, layer thickness and print temperature and the responses studied are energy consumption, CO2 emission, dimensional accuracy, surface roughness and mechanical properties. The primary aim of this research is to reduce the energy consumption and CO2 emission without compromising mechanical properties, in order to achieve sustainability by finding the optimum values for the input process parameters.

This paper investigates the impact of dual phase latency caused by the reflection of plane waves that propagate in a swelling porous thermoelastic medium with an impedance boundary. Two transversal waves (SVS, SVF), a thermal wave (T), and two longitudinal waves (Ps and Pf) propagate with distinct velocities. Reflection coefficients are determined by the incidence of these waves, and energy ratios for reflected waves are calculated and illustrated using these amplitude ratios. In this particular instance, the current model was downsized to an LS model. It has been noted that the energy ratios acquired are significantly influenced by dual phase lag. The results that have been obtained may be beneficial in a variety of engineering problems that are related to structure.

Issues of industrial waste recycling are very relevant for the entire global scientific community. The search for technological solutions that would allow the production of high-quality materials using industrial waste will not only reduce the environmental load, but also expand the raw material base for the production of gypsum materials. The study examined the possibility of improving the surface quality of molded gypsum samples by replacing the metal mold with a plastic one and introducing a surfactant into the raw mixture. As a result of the research, it was found that the use of a surfactant and a plastic mold allows to avoid defects on the surface of the samples. At the same time, the use of a plastic mold, which has low adhesion to the citrogypsum-based binder, helps to reduce the amount of adhesion friction and optimize the raw mixture compaction process. This makes it possible to obtain samples with improved physical and mechanical characteristics (compressive strength increases by 30–85.5%, average density - by 1.7–2.7% and water absorption decreased by 1.7–16%) or lower consumption of binder up to 20% compared to samples prepared in metal mold.

Offshore oil exploration in deeper waters has necessitated the development of lighter mooring systems to replace traditional steel cable and chain platforms. This study focuses on evaluating the mechanical behavior and fatigue degradation mechanism of high modulus polyethylene (HMPE) fibers in yarn-on-yarn abrasion tests. Initial characterization tests, including linear density, rupture force, and thermal analysis, were conducted on HMPE yarns. Yarn-on-yarn abrasion tests were performed under dry, wet, and salty conditions, with varying loads, while statistical analysis examined the influence of environmental factors and load levels on yarn performance. Scanning electron microscopy (SEM) analysis provided insights into material degradation mechanisms. Results showed superior performance in freshwater-immersed yarns due to cooling and lubrication effects, while dry conditions led to material melting. SEM analysis revealed critical degradation zones, particularly in interwoven regions, where increased friction and heat concentration caused material fusion. Degradation evolution mechanisms highlighted fatigue-induced rupture of yarns, knot formation, and material melting near failure points. This comprehensive analysis enhances understanding of HMPE yarn performance and degradation in offshore mooring applications, laying the groundwork for developing advanced mooring systems capable of withstanding deep-sea environments.