Rib Reinforcement Research Articles

Tailored compressive properties of origami thin-walled column with multi-corner elements

To improve the load stability and energy absorption of the energy absorber, a novel design strategy of the cruciform origami column with multi-corner elements (COC) is proposed. The axial compressive test shows that the COC can effectively tailor the deformation mode based on the creases. The comparisons of compressive properties indicate that the COC has lower initial stiffness and higher load stability than the conventional straight column (CSC) and overcomes the disadvantage of the low energy absorption of typical origami columns. In addition, the mechanical advantages of COC with rib reinforcement are more significant. Specifically, the specific energy absorption of COC with cruciform rib reinforcement (COC-C) can increase by 22.98% compared to the COC without rib reinforcement (COC-W), which both have high load stability. Furthermore, the origami module, dihedral angle and thickness have significant effect on tailored deformation characteristics and compressive indicators of the COC, in which the module and dihedral angle can determine the deformation and the trigger effect, respectively. This study finds that the multi-corner elements origami design can improve the compressive properties of thin-walled structures, providing a new design concept for energy absorbers with controlled deformation and load stability.

Rib Reinforcement Bionic Topology Optimization under Multi-Scale Cyclic Excitation

Thin-walled structures have problems such as low stiffness, large deflection, and vibration. The layout of rib reinforcement in thin-walled structures plays a vital role in providing structural strength and rigidity and reducing structural weight. A multi-scale bionic topology optimization method with a cyclic variable load is proposed in this paper to optimize dynamic flexibility by simulating the growth law of leaf vein formation and distribution. A material interpolation method is adopted to penalize the material attributes of rib reinforcement according to their thickness, based on polynomial interpolation. Combined with the layout of rib reinforcement and SIMP, the mathematical model of rib reinforcement layout optimization with cyclic variable loading is proposed, and the sensitivity of thin-walled dynamic flexibility to the rib reinforcement thickness is analyzed. Two typical examples of thin-walled structures are presented to validate the proposed method. Considering the impact effect of multi-scale cyclic loads such as wind speed, pressure, and raindrops acting on the leaf vein, the natural frequencies of bionic topological structures of heart-shaped and elliptical leaf veins are increased by 63.44% and 47.2%, respectively. Considering the change in radial thickness, the mass of the automotive door inner panel with a bionic topological structure increased by 3.2%, the maximum stress value was reduced by 1.4% and 36.8%, and deformation was reduced by 37.6% and 27.1% under the anti-concave and sinking conditions, respectively. Moreover, the first-order natural frequency of the automotive door’s inner panel with a bionic topological structure increased to 30.45%, 3.7% higher than the original.

Comments on effective use of numerical modelling and extended classical shell buckling theory

This paper argues that in the understandable enthusiasm to use the now readily available high-fidelity numerical software allowing the analysis of the complexities of shell buckling, and especially the notorious case of the axially loaded cylinder, there has been insufficient consideration of classical shell buckling theory and its more recent reduced stiffness extension. If future design is to be able to effectively exploit the potential benefits of the use of advanced composite materials and/or the use of rib reinforcement, it is suggested that these numerically driven research programmes would benefit from more explicit integration within the framework of classically extended buckling theory. This suggestion is reinforced in what follows by highlighting the results from a longstanding research programme in which classically extended buckling theory has been demonstrably enhanced through its integration with reliable numerical experimentation. This enhancement has helped to resolve a number of important issues including: identification of the most critical forms of imperfection affecting the buckling loads; how the most critical knockdown factors are influenced by changes in the shells' geometric and material characteristics and how safe design might be more explicitly related to the prescribed levels of geometric tolerances. Recommendations are made as to how such integrated research programmes could in the future further enhance our ability to design materially efficient shells against buckling.

Experimental research on effect of opening configuration and reinforcement method on buckling and strength analyses of spar web made of composite material

Abstract This study experimentally investigates the effect of the opening configuration on the buckling stability and bearing performance of a structural beam web used in a commercial aircraft made of composite materials. The buckling and strength analyses on three opening configurations (circular, oblong, and rhombic) were carried out using test samples with identical web surface size. It is found that the rhombic opening has the minimum effect on the buckling stability and strength of the structure. To compensate for the effect of the opening, two reinforcement methods, using reinforcement rib and thickening the sample, were also investigated in this study. It is concluded that thickening the sample can more effectively improve the buckling stability and strength performance of beam web structure and hence has relatively higher structural reinforcement efficiency.

Sound Transmission Loss of a Metal Panel With Rib Reinforcements and Pasted Damping

The sound transmission losses (STL) of a metal panel with rib reinforcement (MPRR) are studied by both an experimental method and a simulation approach. The experimental method and data processing technique for obtaining STL are presented. Six MPRRs with different number of rib reinforcement and different geometry size of rib reinforcement, and six MPRRs with different type of the pasted damping material are designed and anufactured, and their STL performances are investigated by experimental method. The calculation model for STL of a MPRR is proposed and the calculated STL are compared favorably with the experimental data, which validates the proposed model. The analytical methods and conclusions are instructive for the design and the tuning of STL of MPRRs.

К задаче устойчивости пластины, усиленной ребром жёсткости на свободном крае

К задаче устойчивости пластины, усиленной ребром жёсткости на свободном крае

3D Woven fabric with cross rib as a composite reinforcement

A woven 3D composite is a new type of an advanced construction material. A prototype of three dimensional (3D) textile based on combination of a flat textile with two intersecting tunnels with a rectangular cross-section was constructed and the feasibility of this type of weaving was studied. Prototype of 3D woven fabric was made.Based on 3D textiles preforms composites for the mechanical trial was made. Composites used for strength tests were made using a vacuum infusion method. The basic elements of the composite, that is the flat part and the element with the rib, were selected for testing. This selection resulted from a complicated process of making a composite based on the entire fabric. A 3D composite, created through the lamination of two flat fabric, was also made for comparison. The study compared the material strength with and without rib reinforcement. Tensile and bending test was made. The analysis of the third composite was aimed at demonstrating the purpose of implementing the complicated weaving process.The laminate reinforced with 3D fabrics made from a unified weaving process is characterised by the best mechanical properties of the tested variants. The results can be considered to be encouraging.

Sound transmission loss properties of truss core extruded panels

The car body structures of modern trains are often formed of extruded aluminium panels. Their acoustic properties, particularly the sound transmission loss, have an important influence on the interior acoustic environment. In order to study the acoustic performance of extruded panels, their Sound Transmission Loss (STL) is studied using the coupled Wavenumber Finite Element method (WFE) and Wavenumber Boundary Element method (WBE). The damping of a typical structure is first measured in the laboratory to give suitable input values for the model. The predicted STL is compared with corresponding measurements of the sample panel, with good agreement above 400 Hz. Based on the validated model, an extensive parametric study is carried out to investigate the effect of different reinforcement rib styles on the STL. The effect of using extruded panels with rectangular, triangular and trapezoidal truss-core sections is studied in detail. Among the parameters studied, the number of bays in a given width has a great influence on the sound insulation. Considering practical use, both the mass and stiffness of each case are also considered. To give increased understanding of the STL behaviour, the dispersion curves are also studied. It is found that structures with better STL usually have fewer free wavenumbers below the acoustic wavenumber. For the same number of structural bays, a panel with triangular stiffening has the highest strength but also the largest mass, whereas a structure with rectangular stiffening has the least strength and lowest mass. In the evaluation, the weighted STL Rw and the spectral adaptation term Ctr are considered. The results are also considered relative to a mass law adjustment of the STL. It is found that the three cases which give the best results are a triangular rib panel with 4 or 5 bays in a 1 m width, and a trapezium case with 5 bays and inclination angle 25°. These have an Rw that is 2–6 dB better than the reference panel, a smaller mass and a higher stiffness.

Flow-control and hybridization strategies for thermoplastic stiffened panels of long discontinuous fibers

The current research aims at mitigating the flow-induced manufacturing issues (strand waviness and swirling of strands) encountered in complex parts of randomly oriented strands, through the hybridization of randomly oriented strands with continuous fibers, while emphasizing the ease of manufacturing and repeatability. Three hybridization strategies are proposed for T-stiffeners that represent the generalized intersecting junctions of stiffened panels. The strategies include: flow-control element, flange reinforcements, and rib reinforcements. A quantitative assessment of pull-out strengths of five T-stiffener configurations is made. Flow-control element improves the strand flow at the junction, reduces variability, and enhances the pull-out b-basis design allowable by about 24%. A quasi-isotropic laminate as flange reinforcement with a flow-control element produces 12.5% pull-out strength improvement. Rib reinforcement causes reinforcement delamination from the randomly oriented strands part, dropping pull-out strength by about 6%. A transient heat transfer analysis of the tooling set-up was simulated using finite elements to devise a preferential cooling strategy that minimizes porosity in randomly oriented strands panels with T-stiffeners.

5軸制御マシニングセンタで創成する小型高強度ベベルギヤのリブ形状の検討

We have developed a small size and high strength spiral bevel gear fabricated by five axis controlled machining center. In the present report, we propose a novel spiral bevel gear with the rib at the end of tooth width to reinforce the tooth bending strength, which is machined with a ball-nose end-mill tool. We investigate the influence of the rib shape on the bending stress at the tooth root and the tooth deflection and demonstrate the effect of rib reinforcement at the proposed spiral bevel gear. As a result, a guideline is found to design the small size and high strength spiral bevel gear with the rib at the end of tooth width from a view of rib shape.

The effectiveness of new austrian tunnelling method (NATM) for hydro power plant construction: lau gunung power plant, north sumatera, indonesia

Hydro Electric Power Plant is a power generating system using gravity fall of water as the main force to move the turbine and generate electricity. The construction purpose of Lau Gunung hydropower (2×7. 5 MW) that is located in Dairi, North Sumatra, is to Supply power to 14,000 house of the surrounding region. The river run-off system, where the water is immediately contained and then flowed through a tunnel considering the discharge flowing river, where it is constant and does not occur in the fluctuating water level. The Lau Gunung river has the minimum flow that can exceed from 15 to 25 m 3 /s with a high tunnel dimensions of 4 metres long, 3,9 metres wide and a length of 1,6 kilometres. In terms of the analysis of the time effectiveness of the NATM can be saved because of the continuous work of 24 hours, without any obstacles in which the sub methods used include the drilling & blasting. The tunnel then use the form of steel reinforcement rib and Safety shotcrete lining. The general review may show that using NATM result a tremendous savings, also the use of horse shape conduce small displacement which is effective for the construction.

Effect of an aluminum driver sheet on the electromagnetic forming of DP780 steel sheet

Some experimental studies have proved that materials with low electrical conductivity and even nonconductive materials can be formed using driver sheets with high electrical conductivity. This study investigated the effect of an aluminum driver sheet on the forming peak height of advanced high-strength steel sheet (AHSS) in the electromagnetic forming (EMF) process. DP780 workpieces were formed into a hemi-elliptical protrusion shape, analogous to a reinforcement rib, with various thicknesses, sizes, and material types of the aluminum driver sheets. These experiments were performed with a flat spiral coil actuator connected to the EMF system with a high energy capacity. In addition, three-dimensional coupled electromagnetic-mechanical finite element (FE) simulations were conducted to analyze the effect of the aluminum driver sheet on the forming peak height of the high-strength steel sheets and to predict the proper configuration of the aluminum driver sheet.

617 5軸制御マシニングセンタにより創成される小型高強度スパイラルべベルギヤの特性に関する考察(GS11,13 工作機械制御,研究討論セッション)

We have developed a small size and high strength spiral bevel gear fabricated by five axis controlled machining center. In the present report, we propose a novel spiral bevel gear with the rib at the end of tooth width to reinforce the tooth bending strength, which is machined with a ball-nose end-mill tool. We investigate the influence of the rib shape on the bending stress at the tooth root and the tooth deflection and demonstrate the effect of rib reinforcement at the proposed spiral bevel gear. As a result, a guideline is found to design the small size and high strength spiral bevel gear with the rib at the end of tooth width.

Strength and Modal Analysis of Thin-Shell-Structured Vessel with Rib Reinforcement

The Thin-shell-structured vessel with rib reinforcement is a key structure in petrochemical industry. For large scale and lightweight vessels design, it is essential to optimize the design based on the strength and modal analysis. In this paper a FEM model of Thin-shell-structured vessel with rib reinforcement was set up using Ansys software. It uses finite element programming to calculate its strength and modal numerically. The results indicate that the structure’s strength distribution, displacement distribution and situations about the first-six orders frequency of the vessel structure. Analysis of the calculation provides the numerical and theoretical supports of liquid vessels design under real working conditions.

The Optimal Design of Reinforcement Rib Based on the Orthogonal Test and Finite Element Analysis

the reinforcement rib design is one of the key parts in entire bottle design. This paper presents the optimal design of reinforcement rib is based on the orthogonal test and finite element analysis, which is according to the finite element analysis results as its test data, with the target of the minimum stress, analyses the influence of each size of the reinforcement rib on the stress, obtain the optimal design proposal. The results show that the orthogonal experiment method can effectively distinguish different influence of various parameters on the stress, analyze the optimal design proposal, meanwhile, it can guide the bottle design in practical terms.

Modal Analysis and Optimization Design on a Vehicle-Load Rectangle Liquid Containers under Fluid-Structure Coupling

This paper addresses vibration characteristics issues of a rectangle liquid container under both empty and fluid-structure coupling conditions. It uses finite element programming to calculate different rib reinforcement liquid container structures numerically. Results of the calculation provide the numerical and theoretical supports of liquid containers design for the series of engineering conditions.

The Reinforcement Rib Performance Prediction Based on the BP Algorithm and the Finite Element Analysis

The reinforcement rib design is one of the key parts in entire bottle design. This paper presents the rib performance prediction system based on the BP algorithm and the finite element analysis, which adopts the finite element analysis results as its learning samples, sets up the rib performance prediction system with BP artificial neural network. The results show that the artificial neural network plays an important role in rib performance prediction; meanwhile it can guide the bottle design in practical terms.

Effect of the stiffness and inertia of a rib reinforcement on localized bending waves in semi-infinite strips

This paper reports an analytical and numerical study of localized bending waves in a thin elastic isotropic semi-infinite strip with a rib reinforment. Such waves can be considered as spatially non-uniform bending perturbations localized near free edges, similar to Rayleigh waves decaying exponentially with the distance. From the analysis of localized bending waves in thin elastic structures it may be possible to infer the presence of imperfections, cracks or inclusions, in the structure. In this study, a semi-infinite strip, simply supported on two edges and reinforced on the free one, is considered. A general solution is presented and the conditions under which localized bending waves exist are derived. The mathematical model, accompanied by numerical simulations, reveals that the presence of a reinforcement rib can suppress localized bending waves. This effect is mainly due to the stiffness coming from the rib, rather than from its added inertia terms.

329 シェル構造体の高強度化(材料の動的特性)

Shell structure is one of the most popular structures that are used for the frame of the automobiles and the airplanes. Rib reinforcement method is one of the reinforced methods of the shell structure. In this paper, the best method of rib reinforcement is investigated using structural analysis and stiffness test. The main results are as follow. (1) Rib reinforcement is effective in reinforced method of the shell structure. (2) Rib reinforcement that is attached in the direction of the maximum and minimum principal stress is the most effective to reduce the value of stress and displacement. (3) A lightweight bicycle frame was produced based on these results.

Experimental Study of Cyclic Seismic Behavior of Steel Moment Connections Reinforced with Ribs

A simplified design procedure as well as load transfer model for rib-reinforced seismic steel moment connections was proposed recently. As a followup study, an experimental program was implemented to verify the proposed procedure and to develop schemes that would prevent cracking at the rib tip. All the specimens designed following the proposed procedure exhibited satisfactory levels of connection plastic rotation. A combined strategy of rib reinforcement plus slight trimming of the beam flange in the form of a radius cut pushed the plastic hinging and local buckling of the beam away from the rib tip and effectively reduced the cracking propensity at the rib tip. The strut action of the rib and resulting reverse shear in the beam web were also identified through the strain gage readings in this experiment.