Maximum Bending Force Research Articles

Strength, pliability, and hydrophobicity of mung bean starch straws: Orientation change caused by annealing time.

To achieve starch straws with high strength and large toughness, the effects of annealing time on structural and functional performances of mung bean starch straws were studied. The results revealed that with increasing annealing time from 0to 60min, the ratios of 1047cm-1/1022cm-1 in Fourier transform infrared spectroscopy decreased from 1.37 to 1.20, and the relative crystallinities decreased from 12.09% to 11.01%. The relative crystallinity increased to 13.28% when annealing time increased to 120min. The maximum bending force increased from 10.93 to 104.24 N, and modulus of elasticity enhanced from 0.93 to 62.68 N/mm when annealing time increased from 0 to 120min. Starch straws annealed for 120min had the lowest water absorption (94.61%), while starch straws annealed for 60min had the highest water absorption (127.38%). This outcome not only lay a theoretical foundation for preparing biodegradable starch straws with excellent performance, but also apply for beverages, food container, food packaging films, and so on, strongly promoting starch industrial transformation and development.

Non-planar additive manufacturing of pre-impregnated continuous fiber reinforced composites using a three-axis printer

Non-planar additive manufacturing (AM) demonstrates great potential in enhancing interlayer bonding force and surface smoothness of parts, offering a more flexible design and manufacturing approach for continuous fiber composites to fully exploit material capabilities. This study developed a three-axis printer utilizing an adjustable fiber printing head that can achieve non-planar slicing (NPS) AM of pre-impregnated continuous fibers. The research delves into the influence of deposition inclined angle on the surface roughness of printed samples, enabling the design and printing of NPS samples using continuous carbon fiber (CF), glass fiber (GF), and hybrid fiber composites. The investigation also assesses bending failure morphologies of the printed parts and validates the efficacy of the NPS method through the fabrication of the double-sinusoidal curved surface structure and spherical surface grid structure. The results indicated that maintaining a deposition inclined angle below 15° is crucial to ensure surface accuracy in continuous fiber printed parts. Curved surface bending samples printed with NPS method exhibit substantial enhancements in bending performance and surface accuracy compared to those produced using planar slicing (PS). The NPS-CF sample achieves a remarkable increase of over 170% in maximum bending force and a 63% reduction in surface roughness compared to the PS-CF sample.

Bending behavior of multi-layer sandwich composites reinforced with weft-knitted spacer fabrics

In this study, the bending properties of multi-layer sandwich composites (MLSCs) were investigated. For this purpose, first, 1 × 1- and 5 × 5-Rib gaiting weft-knitted spacer fabrics were produced using E-glass yarns. Then, glass/epoxy sandwich composites were prepared using produced fabrics as reinforcement and epoxy resin as matrix. Considering both the pattern of reinforcements and the arrangement of layers, different types of MLSCs were fabricated by the implementation of different stacking sequences. The prepared samples were subjected to the three-point bending test. Generally, the orientation of samples, structures of each sandwich’s layer, and stacking sequence of layers, as three impressive parameters affected the bending behavior of MLSCs. The results showed that in all samples, the maximum bending force (MBF) of MLSCs in the longitudinal direction is generally higher than that in the transverse direction. The MBF of MLSCs included both 5 × 5-Rib gaiting layers and 1 × 1-Rib gaiting layers increased with increasing the number of 5 × 5-Rib gaiting layers to 1 × 1-Rib gaiting layers. The MBF of MLSCs included of same number of 5 × 5-Rib gaiting and 1 × 1-Rib gaiting structures increases by placing the 5 × 5-Rib gaiting fabrics in the bottom layers, which shows the influence of stacking sequence on the bending behavior of MLSCs. According to the generated geometrical models, two-layer MLSCs are numerically simulated using the FEM. FE simulation and the experimental results brought about the same bending behavior of MLSCs.

Experimental and Numerical Analysis of the Three-Point Bending Behavior of Hybrid Adhesive-Bonded Aluminum–Wood Plates

Hybrid components of wood-based materials offer a high potential for automotive lightweight applications. To investigate the bending behavior of hybrid aluminum-wood plates, commercial 1-mm-thick sheets of EN AW-6016-T4 aluminum alloy were adhesive-bonded with 4.2-mm-thick plates of birch wood. Orientations of the wood fibers parallel (longitudinal) as well as perpendicular (transverse) to the rolling direction of the aluminum alloy sheet and three different moisture contents of the wood plate were considered. The hybrid aluminum-wood plates were subjected to three-point bending at room temperature. Simple wood plates without aluminum alloy sheets were also tested. The bending force-bending angle curves monitored during bending, the bending angles at maximum bending force and the surface strains were evaluated. Moreover, a finite element model of the testing setup was created using the LS-Dyna software. The different moisture contents did not significantly influence the bending angle; however, moisture decreased the maximum bending force. Debonding was identified as critical failure mechanism. The FE model that considered the experimentally determined material properties was able to predict the bending behavior for different moisture conditions.

Crash-worthiness analysis of hollow hybrid structural tube by aluminum with basalt-bamboo hybrid fiber laminates by roll wrapping method

Hollow hybrid structural tubes were evaluated using commercial-grade Diamond Micro Expanded Mesh (DMEM) thin mesh of aluminum (Al) as structural reinforcement. Axial, transverse (flexural), and radial compression tests were performed on four different layered hybrid structures using bamboo (Bm) and basalt (B). With a maximum force of 34.7 kN, compressive ultimate strength of 238 MPa, and strain of 12.6%, AlBmB (with layers labeled from inside to outside) was the best performer in the axial compression test. AlBmB’s adaptability was demonstrated by the flexural test, showing a maximum bending force of 4.7 kN, a flexural strength of 97.7 MPa, and a decreased deflection of 13.2 mm. Radial compression test results underscored the superior energy absorption characteristics of AlBmB. The varying material interfaces in the hybrid tubes yielded distinctive performances. AlBmB, incorporating bamboo and basalt layers, stood out with superior energy absorption and crush force characteristics, indicating enhanced crashworthiness. The other hybrids AlBm, AlB, and BmB also exhibited commendable performances, emphasizing the adaptability of different material combinations. The meticulous selection of DMEM and innovative roll wrapping method for fabrication reliably influenced the tubes’ mechanical properties. The study contributes to advancing the design of lightweight, durable, and high-strength components.

Development of a rapid-shaping and user-friendly membrane with long-lasting space maintenance for guided bone regeneration.

The success of guided bone regeneration (GBR) surgery depends largely on the use of GBR membranes to maintain space for bone regeneration and prevent soft tissue ingrowth. However, currently available commercial degradable GBR membranes are often limited by poor space maintenance ability and require additional suture or nail for fixation. To overcome these limitations, we developed a rapid-shaping, adhesive, and user-friendly GBR membrane (PLGA film-PGN) with long-lasting space maintenance by immersing an electrospun poly(lactide-co-glycolic acid) film in a photo-crosslinkable hydrogel composed of polyethylene glycol diacrylate, gelatin methacryloyl, and nanosilicate (PGN). The PGN hydrogel significantly improved the mechanical strength of the PLGA film-PGN and endowed it with plasticity and adhesive properties, making it more maneuverable. The maximum bending force that the PLGA film-PGN could withstand was over 55 times higher than that of the HEAL ALL film (a commonly used commercial GBR membrane). PLGA film-PGN also promoted the proliferation and osteogenic differentiation of rBMSCs. According to a critical-size rat calvarial defect model, PLGA film-PGN maintained the space within the defect area and significantly enhanced bone formation 4 weeks after the surgery. To conclude, the study provided a novel perspective on GBR membrane design and the multifunctional PLGA film-PGN membrane demonstrated great potential for bone defect reconstruction.

Mechanical Performance of Heat-Treated Norway Spruce (Picea abies) Wood

In this study, the mechanical characteristics of Norway spruce wood (Picea abies) from Bosnia and Herzegovina were investigated by thermal treatment at three different temperatures (specifically, 180, 190, and 210°C) and treatment durations (namely, 2, 3, and 4 hours). For this purpose, the maximum 4-point bending force, the modulus of elasticity in bending, the compression strength parallel to the grain, and the compression strength perpendicular to the grain in treated and untreated specimens were evaluated. Results indicated that the relationship between temperature and duration modification affects the mechanical properties of wood specimens. The results revealed that the relationship between temperature and duration modification influenced the mechanical properties of the wood samples. Specifically, in terms of compression strength, it was observed that the heat-treated specimens exhibited improved mechanical properties compared to the unmodified specimens. However, for the maximum 4-point bending force and modulus of elasticity, the results indicated a decrease in mechanical properties.

A Novel Composite Helicopter Tail Rotor Blade with Enhanced Mechanical Properties

This paper describes the transition towards a composite structure, with the same overall aerodynamic characteristics, for a tail rotor blade of an IAR330 helicopter. The newly proposed structure of the composite blade is made of a carbon-roving spar embedded with epoxy resin, a hexagonal-cell honeycomb core manufactured by fused deposition modelling, and an outer skin made of multiple carbon-fibre-reinforced laminae. The blade was manufactured by the authors using the hand lay-up method at a scale of 1:3 with respect to the real one, and all stages of the manufacturing process are extensively described in the paper. The experimental tests were performed on an Instron 8872 testing machine by applying a bending force on its free edge, similar to the testing methodology employed by various composite blade manufacturers. A three-dimensional numerical model of the tail rotor blade was conceived, analysed using the finite element method, and validated by comparing the numerical and experimental values of the maximum bending force. Further, the model was used for a complex finite element analysis that showed the very good behaviour of the proposed composite blade during flight and emphasized the main advantages brought by the proposed composite structure.

Influence of fibre orientation, moisture absorption and repairing performance on the low-velocity impact response of woven flax/Elium® thermoplastic bio-composites

The importance of natural reinforced bio-composite materials with desirable properties such as high modulus-to-weight ratio, good impact resistance, and the ability to be easily repaired is crucial in the industry. A woven flax/Elium® thermoplastic bio-composite is manufactured to challenge these needs. Elium® is the only resin that permits the manufacture of large parts with thermoset-like processes, as Liquid Resin Infusion presented in that work. The paper highlights the influence of stacking fibre orientation, moisture absorption, and repair aptitude on its impact resistance. An instrumented drop tower was needed to conduct low-velocity impact tests at several energies and high-speed image coupled with microscopic observations was used to assess the damage evolution. The impact resistance was improved for the dry (0/90)6 orientation, but moisture absorption decreased its impact peak force by 20%. A three-point bending test was preferred to compression after impact for studying the residual properties after impact. The bio-composites with (±45)6 orientation showed higher impact residual performance than the (0/90)6 orientation, and corresponded to the reduction of maximum bending force by 20% than that of the reference. In addition, a thermo-compression process was applied to repair the impacted plates and conduct multiple impact/repair cycles which showed a significant recovery of stiffness and maximum impact force at 4J on (0/90)6 plates, highlighting their potential for repair in the automotive and marine industries.

Study of Earthquake & Analysis of Multi-storied Building Using E-Tab

Abstract: Structural Analysis is a branch which includes in the determination of conduct of constructions to anticipate the reactions of various underlying segments because of the impact of loads. Every single construction will be exposed to possibly one or the gatherings of loads, the different sorts of loads typically considered are dead loads, live loads, wind load IS:875-1987 Part1, 2, 3, seismic load (IS:1893-2016). ETABS (Extended Three-Dimensional Analysis of Building System) is a product which is joined with all the significant forces that are static, dynamic, Linear and non-direct, and so on. This Computer programming's are additionally being utilized for the computation of forces, bending moment, stress, strain &deformation or diversion for a complex underlying framework and this software is utilized to design and plan the structures. The study of this project is to analyse & design of Reinforced Concrete building using Etabs. By this project, it has been checked that the displacement of the building seems to be within permissible limit'. The Structure has been designed as per Indian Codes & by laws provided by that area. In this paper, an analysis has been done on the storey height of a building situated in zone V, keeping the base dimensions constant, to find the maximum bending and shear forces at the design for earthquake load, using the software ETABS. For earthquake loads, both dynamic and static analysis has been done. The analysis for seismic loads has been carried out. Thereafter, the graphs for different values displacement at all the storey drifts, due to earthquake load (EQ) have been plotted.

Study on the Bending Behaviors of a Novel Flexible Re-Entrant Honeycomb

Abstract In order to further improve the bending performance of the traditional re-entrant (RE) honeycomb, a novel auxetic honeycomb architecture, called RE-L honeycomb, was proposed by adding an additional link-wall structure to the RE cell. The bending behaviors of the novel RE-L honeycomb, including the properties under linear elastic deformation and the bending behaviors under large deformation, were comprehensively investigated by the analytical, numerical, and experimental models. Results show that the proposed RE-L honeycomb significantly improves the bending compliance in the x-direction due to the highly flexible performance of the additional structure, where the bending rigidity and the maximum bending force are only 23% and 29.4% of those of the RE honeycomb, respectively. Besides, the additional structure obviously improves the designability and orthotropic properties of the original auxetic honeycomb. In conclusion, the proposed RE-L shows improved bending performance, which deserves more attention in future research and related applications.

Characterization of the Mechanical Properties of Selectively Embossed Sheet Metal Materials Under Multi-Axial Loads

The application of embossed structures close to the sheet surface allows for work hardening to be introduced into sheet metal materials, leading to an improvement in their mechanical properties. So far, this was demonstrated in previous research work via tensile tests with differently embossed dual-phase steel specimens. Since tensile tests only reproduce uniaxial loading of the sheet metal material, no conclusions can yet be drawn about the property modification that can be achieved by near-surface embossing concerning real-life, multi-axial loading scenarios. To get deeper knowledge about the deformation behaviour of embossed components, it is important to consider multi-axial load cases. In the investigations reported in this paper, a multi-axial load case was realized by testing embossed bending specimens of DP600 and DP800 using a three-point bending device. The tests showed an overall improvement in the maximum bending force needed for the three-point bending test due to embossing of the materials investigated. Further, the tests indicated that lower-strength materials get more influenced by embossing than higher-strength materials. By simulating the process of embossing the bending specimens and the subsequent three-point bending test, an even deeper understanding of the material property modification could be generated.

3D-Printed PLA Molds for Natural Composites: Mechanical Properties of Green Wax-Based Composites.

The first part of this paper is dedicated to obtaining 3D-printed molds using poly lactic acid (PLA) incorporating specific patterns, which have the potential to serve as the foundation for sound-absorbing panels for various industries and aviation. The molding production process was utilized to create all-natural environmentally friendly composites. These composites mainly comprise paper, beeswax, and fir resin, including automotive function as the matrices and binders. In addition, fillers, such as fir needles, rice flour, and Equisetum arvense (horsetail) powder, were added in varying amounts to achieve the desired properties. The mechanical properties of the resulting green composites, including impact and compressive strength, as well as maximum bending force value, were evaluated. The morphology and internal structure of the fractured samples were analyzed using scanning electron microscopy (SEM) and an optical microscopy. The highest impact strength was measured for the composites with beeswax, fir needles, recyclable paper, and beeswax fir resin and recyclable paper, 19.42 and 19.32 kJ/m2, respectively, while the highest compressive strength was 4 MPa for the beeswax and horsetail-based green composite. Natural-material-based composites exhibited 60% higher mechanical performance compared to similar commercial products used in the automotive industry.

Comparative Study of Analysis and Design of Pre-Engineered- Buildings Using Staad Pro Software

Abstract: The STAAD-PRO offers an even bigger advantage over the manual procedure since it produces results that are more exact and precise. As the members are designed, using PEB construction instead of the Conventional Steel Building (CSB) design idea provides many benefits. With the use of conical IS sections, the PEB structure is designed in accordance with the bending moment distribution diagram along the whole span of the beam and column, therefore lowering the demand for steel.The stiffness matrix method is used to assess the basic framework of PEB systems. The structure's design geometry, load, and desirable load combinations as required by the user-selected building code are produced using acceptable voltage design (AVD) in compliance with the American Institute of Steel Construction or IS 800 specification in various modes. To produce a workable design, the software runs through the maximum number of cycles specified. The maximum displacement beam that results is 0.530. The end girder has a maximum shear force (Fy) and bending force (Mz) of 2.541 KN and 4.381 KN-m, respectively

Effects of different rapid cooling temperatures and annealing on functional properties of starch straws after thermoplastic extrusion

To improve the performance of starch straws in rapidly cooling and annealing procedure of thermoplastic extrusion, control straw was prepared through slowly cooling at 25 °C, and starch straw was prepared through regulating different rapid cooling temperatures including 20 °C, 5 °C, −10 °C and −20 °C. The results indicated that control straw exhibited a homogeneous state, while starch straws treated by rapid cooling displayed like a wash-board structure. Compared to control straw, the ratio of the absorption peak intensity of 1047 and 1022 cm−1 increased from 1.050 to 1.455 as cooling temperatures decreased from 25 °C to −20 °C, indicating short-range order of the double helix structure significantly enhanced. The relative crystallinities of starch straws increased from 12.01 % to 16.58 %. The maximum bending force value (60.92 N) of starch straws cooled at −20 °C was significantly higher than that (46.14 N) of control straw. Conversely, the modulus of elasticity in bending values (4.21–16.43 N/cm) of rapid cooling-treated straws were significantly lower than that (48.42 N/cm) of control straw. Water absorption of rapid cooling-treated straws were lower than that of control straw, indicating the hydrophobicity property of starch straws significantly improved.

Collision characteristics of the intermediate coupler of a rail vehicle

Suppose the intermediate coupler of a rail vehicle is unstable during the collision process and loses its connection and energy dissipation functions. In that case, it will significantly reduce the performance of the train crashworthiness function and increase the risk of train derailment. This paper aims to establish a refined finite element model (RFEM) that can simulate the buckling behaviour and investigate the bending resistance and buckling instability characteristics of the intermediate coupler, and the accuracy of the RFEM was verified by quoting the results of an existing intermediate coupler impact test. The results demonstrated that the proposed coupler modelling method could better simulate the energy absorption characteristics and unstable behaviour. Compared to the test results, the differences in the initial crushing force, maximum longitudinal compression displacement, minimum crushing force, and maximum crushing force were 6.5%, 1.3%, 3.6%, and 6.5%, respectively. Within the allowable range of parameters, the maximum bending force linearly increased with an increase in the initial longitudinal compression displacement. As the pitch or yaw angle increased, the longitudinal buckling load of the coupler linearly decreased and became more sensitive to the pitch angle. When pitch and yaw angles existed simultaneously, the longitudinal buckling load was further reduced.

(Digital Presentation) Fabrication and Characterization of C-MEMS Based 3-Dimensional Microelectrode Arrays for Cardiac Electrophysiological Studies

In-vitro examination of the electrical conduction characteristics and the beating of cardiomyocytes can be done using Microelectrode arrays(MEAs). The microelectrodes continuously monitor the electrical activity of the active cardiac cells on a microsecond timescale and presents a precise data based on that. Since the introduction of MEAs, many efforts have been made by scientists to evolve this technology by means of microfabrication. Previously, planar metallic electrodes were mostly used for this study but they could not penetrate the dead cells and reach the active cell layers. To overcome this, protruding 3-D microelectrodes were introduced that could puncture the dead tissues and reach the active cells for effective recording of cardiac electrical potentials.The characteristics of an electrode are defined by the characteristics of the material used to develop it. In this paper, we focus on the fabrication of cylindrical 3-dimensional Glassy Carbon microelectrode arrays (MEAs) for analyzing cell preparations from cardiac tissues. In order to improve the electrical properties of the commercially available electrodes, we have used a highly conductive material for fabrication. Glassy Carbon microelectrodes were fabricated by the pyrolysis of SU-8 microelectrodes which were developed by a standard lithographic process on Silicon wafer. The ohmic nature and high conductivity of Glassy Carbon makes it a suitable material to be implemented in electrophysiological studies. Further in our work, we have performed the theoretical and structural analysis using Comsol Multiphysics 5.2 considering different geometries of microelectrodes. The skin insertion force is calculated to be 0.012N, which is much lesser than the comprehensive force (15.38N), the maximum bending force (0.885N) and the maximum buckling force (3.28N) per cylindrical microelectrode. The maximum Von Mises stress (as shown in the figure) acting at the base where it is attached to the substrate is found out to be 6.56x106 N/m2 for each cylindrical microneedle. Among all the considered geometries, it can be concluded that the fabricated cylindrical microelectrodes penetrate successfully without breaking or bending and causing minimal damage to the cardiac tissues. The slanted tip microelectrode was also favored as it’s design makes it able to easily pierce the cardiac cell layers. However, the Maximum Von Mises stress distribution showed that the stress at the tip was much higher than the Yield strength of Glassy Carbon (4Gpa) making it evident that the tip might break while penetrating. With the theoretical and simulation analysis performed we were thus able to optimize the geometry and establish that Glassy Carbon proves to be a good material for fabrication of 3D microelectrode arrays. Figure 1

Different properties of poly(L-lactic acid) monofilaments and its corresponding braided springs after constrained and unconstrained annealing.

Thermal annealing is widely applied to enhance the mechanical performance of PLLA monofilaments, which brings in a variety of expected strengths through different constrained methods. In this work, samples with constrained and unconstrained annealing process were both prepared and characterized, including mechanical performance, surface morphology, radial supporting performance and axial flexibility. Experimental results revealed that the monofilaments under constrained annealing showed higher elastic modulus with 6.4GPa, which were higher than those without any constraint. While the maximal elongation at break with 51.11% were observed in unconstrained annealed monofilaments. Few changes were presented in the molecular weight between the two types of samples. Moreover, the springs under constrained annealing inhibited the most reliable radial supporting performance with higher radial compression force and chronic outward force, 0.665N/mm and 0.14N respectively. However, unconstrained annealing springs showed better flexibility with 0.178N bending stiffness and 1.58N maximum bending force. These results suggested that filaments and springs with various properties can be obtained under different annealing conditions.

The Use of Artificial Neural Networks for Determining Values of Selected Strength Parameters of Miscanthus × Giganteus

The aim of this paper is to develop neural models enabling the determination of biomechanical parameters for giant miscanthus stems. The static three-point bending test is used to determine the bending strength parameters of the miscanthus stem. In this study, we assume the modulus of elasticity bending and maximum stress in bending as the dependent variables. As independent variables (inputs of the neural network) we assume water content, internode number, maximum bending force value and dimensions characterizing the cross-section of miscanthus stem: maximum and minimum stem diameter and stem wall thickness. The four developed neural models, enabling the determination of the value of the modulus of elasticity in bending and the maximum stress in bending, demonstrate sufficient and even very high accuracy. The neural networks have an average relative error of 2.18%, 2.21%, 3.24% and 0.18% for all data subsets, respectively. The results of the sensitivity analysis confirmed that all input variables are important for the accuracy of the developed neural models—correct semantic models.

Laboratory Investigation into the Flexural Behavior of Embedded Concrete Sleepers in Two-Stage Concrete with Preplaced Ballast Aggregate

The conversion of ballasted railway tracks into slab tracks using the preplaced aggregate concrete (PAC) technology over the bridges and in the tunnels has been introduced by many researchers but the flexural behavior of this composite system has not yet been studied. Therefore, in the first stage, a series of mortar and concrete mixture designs were proposed and evaluated. Subsequently, a concrete beam mold with dimensions of 3 * 0.6 * 0.5 m, which represented the track conditions, was developed and the bending behavior of the constructed beams in both conditions of the presence and absence of the concert B70 sleeper were investigated. The maximum bending force in the middle of the concrete beam without a sleeper (SE) equaled 177.5 kN. In addition, the average values of bending tolerance by the sleeper including a PAC beam for three specimens in the four modes of the positive moment of midspan (SPM), negative moment of midspan (SNM), positive moment of rail seat (SPR), and negative moment of rail seat (SNR) were 55.25 kN m, 32.5 kN m, 91.84 kN m, and 38.21 kN m, respectively, which met the requirements of the AREMA regulations.