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The authors examined how the arrangement of corrugated board boxes influences the loading unit’s resistance to static pressure. The obtained values were compared with the basic strength test of a single box commonly used, which is the resistance to static pressure of BCT boxes. The subject of the study was FEFCO 201 flap boxes with touching flaps. The scope of work included measuring the static pressure resistance BCT of a single box and eight boxes stacked in two layers in two different ways, which are the most popular techniques for stacking boxes on a pallet when creating a loading unit. The strength of a single box, eight boxes stacked in columns, and eight boxes stacked in a blocking arrangement with overlapping edges was determined. The measurement results were compared, and conclusions were drawn.

Corrugated materials, particularly corrugated board, form the backbone of contemporary packaging due to their light weight and high-strength properties. The application of numerical homogenization techniques to model and predict the mechanical behavior of these materials has evolved significantly, enabling refined structural design and optimization. This review examines advances in the homogenization of corrugated structures, with an emphasis on analytical, numerical, and experimental approaches as applied to corrugated board. Developments in the theoretical modeling of key mechanical properties, such as elasticity, bending, and shear stiffness, are highlighted, alongside methods for predicting structural responses under varying loading conditions. Efforts to optimize structural design through homogenization and the integration of digital tools, including artificial intelligence, are also discussed. Additionally, challenges in adapting homogenization models to account for environmental factors such as humidity and temperature, which impact mechanical properties, are analyzed. The review concludes by outlining future research directions and opportunities for bridging theoretical advances with practical applications in corrugated material design and usage.

A 2D numerical analysis was executed using ANSYS Fluent 16.0 to optimize the dimensions of pentagonal corrugations (corrugation pitch p and angle [alpha]) in the absorber plate of a solar air collector of an indirect solar dryer. Initially, [alpha] and corrugation height (e) were kept constant and varied the p from 50 to 175 mm, and optimized p was found. Hence, there are 36 sets of results (part-A). This optimized p was used in the second set of simulations where [alpha] is varied from 10° to 37.5° with an increment of 2.5°. It has 72 sets of results (part-B). The performance parameters such as Nusselt number (Nu), friction factor (f), Nu ratio, f ratio and thermohydraulic performance parameter (T.sub.hp) were determined for both sets. Nu ratio was from 1.81 to 3.126, which implied that the heat transfer was enriched up to 3.126 times. The maximum T.sub.hp was 1.748 at p = 150 mm. Hence, p = 150 mm is proposed from part-A simulations. In the part-B simulations, the maximum of T.sub.hp was noticed at [alpha] = 35° and 37.5°. Considering the material requirement, dimensions of p = 150 mm and [alpha] = 37.5° are proposed.

Terahertz backward wave oscillators based on double corrugated waveguides are enabling devices for modern satellite communication systems. This research focuses on the design of a 0.34 THz double corrugated waveguide-based interaction structure using a sheet beam. This choice allows the use of shorter pillars along with a narrow gap between pillar rows. Shorter pillars are easier to manufacture and a narrow gap is required for better interaction impedance. Circular beams restrict the use of larger pillars and narrow gap between pillars. The performance of this interaction structure is compared with a folded waveguide. Under the same operating conditions involving a 20 kV beam voltage and a 30 mA beam current, the double corrugated waveguide interaction structure exhibits impressive performance in simulations, featuring an interaction impedance of 0.52 Ω at 0.34 THz, an output power of 3.2 W, and a bandwidth extending to approximately 20 GHz. In contrast, the folded waveguide, as per simulation results, registers values of 0.43 Ω , 2.6 W, and a 12 GHz bandwidth, respectively. The proposed double corrugated waveguide-based interaction structure is fabricated using modern CNC machining. Experimental validation reinforces the effectiveness of this design, with measurements indicating reflection below −20 dB and transmission exceeding −2 dB.

Concrete-filled double-skin steel tubular (CFDST) columns have become widely utilized in building construction and bridges, thanks to their exceptional structural capabilities. Therefore, this study investigates the axial compressive behavior of square CFDST columns. The study aims to explore the influence of external and internal plate shapes (flat or corrugated plates) and different widths of internal steel tubes on the axial compressive behavior. The effects of varying internal widths of the internal steel tube (60 mm, 116 mm, and 160 mm) on the performance of CFDST columns were examined. Additionally, the study compared the performance of concrete-filled steel tubular (CFST) and CFDST columns with external flat or corrugated plates. The findings indicated that incorporating internal corrugated plates notably improved both the load-carrying capacity and ductility of the specimens. Notably, CFDST columns featuring corrugated internal plates (116 mm width) exhibited strength enhancements of 25.3% and 7.4% compared to internal widths of 160 mm and 60 mm, respectively. Furthermore, the study proposed two machine-learning models, namely Artificial Neural Network (ANN) and Gaussian Process Regression (GPR), to estimate the ultimate compressive strength of square CFDST columns. The findings indicated that the GPR model outperformed the ANN model in predicting the bearing capacity of square CFDST columns. Additionally, the Shapley Additive Explanation technique was employed for feature analysis. The outcomes of this analysis revealed that parameters such as section width and concrete strength positively influence the compressive strength index.

The present study deals with the experimental behavior of steel beams with a corrugated section, which is approximately equivalent to a compact I-shape plate girder section. Each part of the compact section (flanges and web) was transformed to its equivalent corrugated shape, depending on the available steel plate in the local market, by two plates separated by internal steel stiffeners of a zek zak shape. Six specimens were fabricated and tested in which one of them was considered as a control beam with no corrugation while the other five ones were with various schemes of corrugation for the flanges and the web . The experimental results showed that an increment of nearly 22% in the ultimate load was obtained when the section’s height increased by 25% due to the corrugation process. Furthermore, the mid-span deflection reduced by 57% as the section’s height increased by 29%. Besides, the modes of failure changed from flexural to shear in all the tested corrugated specimens.

The surface of plant fibers was modified by silane coupling agents to prepare plant fiber/polylactic acid (PLA) composites, which can improve the dispersion, adhesion, and compatibility between the plant fibers and the PLA matrix. In this work, three silane coupling agents (KH550, KH560, and KH570) with different molecular structures were used to modify the surface of waste corrugated paper fibers (WFs), and dichloromethane was used as the solvent to prepare the WF/PLA composites. The effects of different silane coupling agents on the microstructure, mechanical properties, thermal decomposition, and crystallization properties of the composites were studied. The mechanical properties of the composites treated with 4 wt% KH560 were the best. Silane coupling agents can slightly improve the melting temperature of the composites, and WFs can promote the crystallization of PLA. The modification of WFs by silane coupling agents can increase the decomposition temperature of the WF/PLA composites. The content and type of silane coupling agent directly affected the mechanical properties of the WF/PLA composites. The interfacial compatibility between the WFs and PLA can be improved by using a silane coupling agent, which can further enhance the mechanical properties of WF/PLA composites. This provides a research basis for the further improvement of the performance of plant fiber/PLA composites.

Knowing the material properties of individual layers of the corrugated plate structures and the geometry of its cross-section, the effective material parameters of the equivalent plate can be calculated. This can be problematic, especially if the transverse shear stiffness is also necessary for the correct description of the equivalent plate performance. In this work, the method proposed by Biancolini is extended to include the possibility of determining, apart from the tensile and flexural stiffnesses, also the transverse shear stiffness of the homogenized corrugated board. The method is based on the strain energy equivalence between the full numerical 3D model of the corrugated board and its Reissner-Mindlin flat plate representation. Shell finite elements were used in this study to accurately reflect the geometry of the corrugated board. In the method presented here, the finite element method is only used to compose the initial global stiffness matrix, which is then condensed and directly used in the homogenization procedure. The stability of the proposed method was tested for different variants of the selected representative volume elements. The obtained results are consistent with other technique already presented in the literature.

The nonlinear response of driven complex materials—disordered magnets, amorphous media, and crumpled sheets—features intricate transition pathways where the system repeatedly hops between metastable states. Such pathways encode memory effects and may allow information processing, yet tools are lacking to experimentally observe and control these pathways, and their full breadth has not been explored. Here we introduce compression of corrugated elastic sheets to precisely observe and manipulate their full, multistep pathways, which are reproducible, robust, and controlled by geometry. We show how manipulation of the boundaries allows us to elicit multiple targeted pathways from a single sample. In all cases, each state in the pathway can be encoded by the binary state of material bits called hysterons, and the strength of their interactions plays a crucial role. In particular, as function of increasing interaction strength, we observe Preisach pathways, expected in systems of independently switching hysterons; scrambled pathways that evidence hitherto unexplored interactions between these material bits; and accumulator pathways which leverage these interactions to perform an elementary computation. Our work opens a route to probe, manipulate, and understand complex pathways, impacting future applications in soft robotics and information processing in materials.

The research paper is devoted to study of culverts from metal corrugated pipes (CMP) and helically corrugated steel pipes (HCSP). Modern design solutions of culverts from CMP and HCSP are differ as compared with used before (bottom with various types of roughness, inlet and outlet heads, type and size of corrugation) and there is not enough experimental data for their design. The aim of the study is to test CMP and HCSP models to determine their hydraulic parameters, such as roughness and resistance coefficient, critical bias and so on. The laboratory equipment and method of experimental study as well as results of the tests of CMP and HCSP with protective tray at the pipe bottom and without it under different operation modes are given in the research paper. The results of the study show that roughness coefficient under pressure hade mode can be determined using Norton equation only for HCSP, Norton and Einstein-Banks equations are corrected for CMP.