Reinforcement Shape Research Articles

Nanocomposites with cylindrical/rectangular/spherical/ellipsoidal reinforcements: Generalized continuum mechanics

Nanocomposites can show different properties according to the type of reinforcements they have. In this article, a model for the study of nanocomposites is examined, which is able to examine all nanocomposites with elliptical, cylindrical, spherical and rectangular reinforcements. Also, in this model, unlike some other models, the effects of interphase section are included. The results obtained from this model are compared with the results of experimental tests. Also, in present research, instead of classical continuum theories, generalized continuum mechanics is used and combined with above model to present more accurate model for studying nanocomposites. After estimating the material properties of nanocomposites, the static and dynamics behaviors of them are also studied and the influences of various parameters such as volume fraction of interphase section, geometrical shapes of reinforcements, volume fraction of fibers, gradient parameter, nonlocality and magnetic field are investigated on the results.

Effect of Geometry and Size of Fiber Reinforced Plastic Deck Profile on Behavior of Bridges

Due to the important role that bridges play in rescue operations after an earthquake, it is necessary that these structures have a higher level of protection against seismic attacks. Earthquake identifies the weak points of the structure and causes the most damage there. Bridges are very vulnerable to these attacks due to their low degree of uncertainty. All bridges built before 1971 were designed with the elastic design method (permissible stress). In this method, the effects of plasticity, section cracking, and plastic deformation are not taken into account. The change of seismic locations based on the principles of elastic design is much less. It is because the structure experiences in a real earthquake, one of the consequences of which is the falling of the decks due to the loss of the support surface. The decision to strengthen the bridge was made when there were many bending and shear cracks on the king beams. The bridge was created. The use of FRP profiles can significantly prevent the damage caused by corrosion and is a good alternative to the traditional methods of strengthening the structure. In this study, a design for the deck of a steel bridge with I beams is presented. The shape of reinforcement using FRP fibers with vinyl ester resins has also been investigated, the effect of the geometry of FRP profiles has been investigated. The presented specifications are optimized to obtain a lasting shape and section, especially for the pultrusion process. FRP materials are light, resistant to corrosion and have high tensile strength. These materials come in different forms and range from multi-layer factory sheets to dry sheets that can be twisted on various structural forms before adding resin, is available. The durability and high tensile strength of FRP materials are among the advantages of these materials. The durability and long-term performance of FRP requires more research, which is ongoing and continues.

Flexural performance of UHPC-filled narrow joints between precast concrete bridge slabs

The deck slabs narrow joints in concrete bridges filled with Ultra-high performance concrete (UHPC) have the potential for wide application and high-efficiency promotion, but there is limited research available on this topic. This paper conducted flexural tests on the new joints. Ten precast concrete deck panels were designed and manufactured for concrete bridges. These panels were connected using UHPC-filled narrow joints. Combined with stress analysis, this study investigates the influence and mechanism of various factors on the mechanical performance of UHPC joints. These factors include the geometric shape of the joint, the roughness of the joint interface, the filling material used in the joint, the width of the joint, and the configuration of joint reinforcement (including the shape and length of lap reinforcement). The test results show that the panel with the UHPC joint filled with steel fibers has excellent flexural and bonding capacity. The jointed panel with a lap length of 140 mm and 120 mm has better flexural performance than the one with a lap length of 90 mm. The straight-jointed panel has a higher flexural capacity compared to the complex triangular-jointed panel. Additionally, reducing the joint width can achieve similar mechanical properties as before. A method has been proposed for calculating the flexural capacity of a jointed panel, utilizing the strut-and-tie model (STM). This method can accurately predict experimental results.

Mechanical Properties of Wooden Elements with 3D Printed Reinforcement from Polymers and Carbon.

The research presented in this article aimed to investigate the differences in mechanical properties between solid structural timber and the same reinforced element in three different ways. A three-point bending test was performed on wood elements reinforced with carbon-fiber-reinforced polymer (CFRP), 3D printed polycarbonate (3DPC) lamellas, and 3D printed polycarbonate with carbon fiber (3DPCCF) lamellas. In this comparison, the bending strength was large for CFRP samples, which have 8% higher performance than samples with 3DPCCF and 19% higher performance than samples with 3DPC. Conversely, when factoring in theoretical manufacturing costs, the performance of 3DPCCF is almost three times that of CFRP and 3DPC. In addition, 3D materials can be used for more complicated reinforcement shapes than those discussed in the paper.

Уголковые подпорные стены с вертикальными консолями в виде оболочек и складок

The subject of the study is reinforced concrete corner retaining walls, widely used in hydraulic engineering construction. Optimization of the shape of the vertical console of corner retaining walls is important to reduce internal forces and increase the stability of structures. When replacing flat panels with spatial structures in the console, bending moments are reduced; the predominant work of structures for compression or stretching allows reducing their thickness due to more efficient use of materials. The purpose of the study is to determine the optimal shape and nature of reinforcement of vertical retaining wall consoles, depending on their height. The study was conducted in the certified software package “LIRA-CAD2021”. Computational models of corner retaining walls with consoles in the form of multi-wave cylindrical shells and folds have been developed. At the junctions of the waves and the edges of the folds, racks are provided, pinched in the ground. Comparative calculations of structures in the software package “LIRA-CAD2021” were performed. The results of calculations are analyzed. Conclusions are drawn on the optimization of the structures of retaining walls with a vertical console in the form of shells and folds. The study showed that with a retaining wall height of up to 3 m, a retaining wall with a console in the form of a multi-wave shell is more rational in terms of material consumption. At a height of more than 3 m, retaining walls with a console in the form of folds with vertical posts at the interface of the faces become rational. For consoles in the form of shells, double reinforcement is recommended with an increase in the area of the reinforcement in the lower part and at the interface areas of adjacent waves. For consoles in the form of folds, double reinforcement is also recommended, but additional reinforcement is required only in the area of the interface of the panels with the foundation plate.

The Analysis of Stiffness and Driving Stability in Cross-Member Reinforcements Based on the Curvature of a Small SUV Rear Torsion Beam Suspension System

Most small SUVs in the automotive market are equipped with torsion beam suspension for the rear wheels. Torsion beam suspension consists of a cross-member and a trailing arm. The cross-member plays a crucial role in preventing the vehicle from twisting; therefore, a shape that can withstand loads is essential. In this study, various shapes of cross-member reinforcements were added to the existing torsion beam suspension to analyze its structural strength when subjected to arbitrary forces. Analysis results were obtained for stiffness and driving stability factors such as smooth road shake, impact hardness, and memory shake. Based on these results, we identified the optimal cross-member shape with low torsional stiffness and a small side view swing arm angle by examining the changes in driving stability.

Experimental study on the effect of different shear reinforcement shapes and arrangement on 3D crack propagation and shear failure mechanism in RC beams

Surface crack patterns have been considered to determine the shear failure behavior of RC beams but the effect of three-dimensional crack propagation on shear crack development and shear strength of RC beams is still debatable. In this study, a three-dimensional crack evaluation was carried out to investigate the shear failure mechanism of RC beams with different shapes and arrangement of shear reinforcement (close shape shear reinforcement, rod shape reinforcement with mechanical anchorage, combination of close shape reinforcement and rod shape reinforcement, rod shape reinforcement and transverse distribution rebar) using three-point loading test by keeping the amount of shear reinforcement same in all beams. The load displacement relationships, 3D crack maps, stirrup strain and concrete strain relationships with displacement and shear resistance components were discussed in detail and these information’s are useful for designing and shear strengthening of existing beams. It was clarified that a clear difference in three-dimensional cracking pattern, shear resistance components of concrete and shear reinforcement contribution was observed in RC beams. This was due to the shear reinforcement shapes and arrangement of rod shape reinforcement, which influenced the shear strength of RC beams.

Development and validation of a fully automatic tissue delineation model for brain metastasis using a deep neural network.

Stereotactic radiosurgery (SRS) treatment planning requires accurate delineation of brain metastases, a task that can be tedious and time-consuming. Although studies have explored the use of convolutional neural networks (CNNs) in magnetic resonance imaging (MRI) for automatic brain metastases delineation, none of these studies have performed clinical evaluation, raising concerns about clinical applicability. This study aimed to develop an artificial intelligence (AI) tool for the automatic delineation of single brain metastasis that could be integrated into clinical practice. Data from 426 patients with postcontrast T1-weighted MRIs who underwent SRS between March 2007 and August 2019 were retrospectively collected and divided into training, validation, and testing cohorts of 299, 42, and 85 patients, respectively. Two Gamma Knife (GK) surgeons contoured the brain metastases as the ground truth. A novel 2.5D CNN network was developed for single brain metastasis delineation. The mean Dice similarity coefficient (DSC) and average surface distance (ASD) were used to assess the performance of this method. The mean DSC and ASD values were 88.34%±5.00% and 0.35±0.21 mm, respectively, for the contours generated with the AI tool based on the testing set. The DSC measure of the AI tool's performance was dependent on metastatic shape, reinforcement shape, and the existence of peritumoral edema (all P values <0.05). The clinical experts' subjective assessments showed that 415 out of 572 slices (72.6%) in the testing cohort were acceptable for clinical usage without revision. The average time spent editing an AI-generated contour compared with time spent with manual contouring was 74 vs. 196 seconds, respectively (P<0.01). The contours delineated with the AI tool for single brain metastasis were in close agreement with the ground truth. The developed AI tool can effectively reduce contouring time and aid in GK treatment planning of single brain metastasis in clinical practice.

Estimation of flexural modulus of layer graded polymer nanocomposite using finite element and micromechanics approach

The effective bending modulus of layer-graded polymer nanocomposites (LGPNCs) was investigated using finite element modeling (FEM). Five uniform layers of LGPNCs were prepared with varying weight fractions of alumina as the filler material and epoxy as the matrix, ranging from 0% to 1% along their thicknesses. MATLAB code was developed to create representative volume element (RVE) samples, and ANSYS APDL was used for the analysis. The study examined the effect of the shape, weight fraction, and orientation of the nanorod reinforcement on the effective flexural modulus of LGPNCs and polymer nanocomposites (PNCs). The study explored the influence of the interface between the matrix and the nanofillers on the effective modulus of LGPNCs. The simulations results revealed that cylindrical nanorod led to enhanced bending strength in LGPNCs, while such improvements were not observed with spherical nanofillers. The results were compared to the modified Mori-Tanaka (MT) method and showed a high degree of agreement.

Comparative analysis between size and mass ratio of nano-Al2O3 in the performance of dental composite and finding the optimum composition

Dental composites provide better bonding with tooth tissue as compared to other traditional materials such as amalgam. However, the development of dental composites relies on experimental results of physical, mechanical and thermal properties of the dental composite obtained after applying the strategy of filler technology, i.e., changing size, shape, surface modification and mass ratio of filler or reinforcement. In the present research, nano-Al2O3 particle size and filler mass ratio were varied to study their effect on the physical, mechanical and thermal behaviour of dental composite. The particle size was varied in the range of 30 nm, 50 nm and 70 nm. Nano-Al2O3 filler mass ratio was varied in the range of (0, 5, 10 and 15 wt. %). Fourier transform infrared analysis was done to check variations in absorption peak and band in the spectrum due to variation in the filler mass ratio and size. Physical properties, mechanical properties and thermal properties were investigated. It was observed that hardness, compressive strength, diametral tensile strength, flexural strength and stress intensity factor were increased by 133%, 13.6%, 27.4%, 25% and 20%, respectively, on adding 5 wt. % of nano-Al2O3 and decreased by 13.5%, 8.1%, 15.3%, 13.9% and 10.3%, respectively, on increasing particle size from 30 nm to 50 nm. The thermal degradation temperature was increased by 31.8% and 36% on adding 5 wt. % and increasing particle size from 30 nm to 50 nm, respectively. It can be concluded that in the case of nano-sized particulate filler, mass ratio played a more significant role than filler size in regards to optimization of physical, mechanical and thermal properties.

Penerapan Bulding Information Modelling (BIM) Autodesk Revit dalam Pembuatan Bar Bending Schedule (BBS) Pondasi Pile Cap Proyek Apartemen Jkt Living Star - Jakarta Timur

Bar bending schedule is a systeem of bending patterns of reinforcement that includes data on diameter, shape, length and number of reinforcement. The purpose of this study is to obtain images of bar bending schedule documents, pile cap foundation iron volumes and find out whether Autodesk Revit software is more efficient and effective than conventional methods. This research uses quantitative methods and the manufacturing process uses the concept of Building Information Modeling (BIM) with autodesk revit software. The results showed that the use of Autodesk Revit software makes it more effective, especially in making bar bending schedule documents, because everything is made automatically. The volume of pile cap iron produced by Autodesk Revit software is 46,878 kg has a difference with the existing (conventional) volume. The volume result of autodesk revit software is less with a difference of 1.29%. This shows that Autodesk Revit software is more efficient in terms of calculating the volume of concrete iron.

Effect of various reinforcement shapes on the ballistic resistance of reinforced concrete slabs

Concrete structures are often subjected to extreme hazards such as projectile, missile impacts, crash, and blasts. So, evaluation of ballistic resistance of such structures against impact loading has become important. The present study is aimed to evaluate the effects of different shapes of reinforcement on the ballistic performance of slab to improve the state-of-the-art in protective design of structures. A finite element (FE) based model was framed in ABAQUS/Explicit to determine the perforation characteristics of reinforced concrete (RC) targets. The reinforced square targets were impacted by a rigid ogive nose steel projectile for wide range of velocities. Appropriate material models were adopted to simulate the response of concrete and steel reinforcement respectively. The model was validated with the experimental results and further, the validated model was used to perform the numerical simulations. The influence of various shapes of reinforcement on the ballistic resistance of RC targets was evaluated and compared. Among the compared shapes, the extended spiral reinforcement was found to have better ballistic performance. Consequently, the findings of this study can have implications in the design of protective structures.

Review on Reinforcement-concrete Bonded Anchorage

In order to obtain the study of the bonding properties between the reinforcement-concrete and give full play to the material properties, a lot of research has been carried out on reinforcement-concrete. Existing reinforcement-concrete studies contain mainly reinforcement-concrete bonds, reinforcement lap, and anchorage of reinforcement. The reinforcement-concrete bond test mainly measures the bond-slip curve between the two to determine the bond strength between reinforcement and concrete. The reinforcement lap test is mainly used for the performance study of the anchorage length of reinforcement in concrete, whether the lap bars are in contact with each other, which can be divided into two forms: contact lap and indirect lap. The anchorage test of reinforcement is conducted to study the reduction of the connection length between reinforcement and concrete while meeting the force requirements. According to a large number of tests, the bond strength of the reinforcement is affected by the shape of the mixed reinforcement, the thickness of the protective layer of the diameter concrete, the spacing of the reinforcement, the transverse reinforcement restraint, and the material properties of the reinforcement and concrete. This paper discusses the test methods, influencing factors, and the lack of existing research in the study of the performance of reinforcement-concrete bonding, and lap and anchorage properties.

Designing the internal reinforcements of a sailing boat using a topology optimization approach

In naval design it is common practice to define an internal regular web frame made of longitudinal elements and transversal sections with the purpose of giving stiffness to the whole structure and, at the same time, promoting lightness. In this work, FEM simulation and Topology Optimization (TO) tools are implemented to present a different approach in placing the reinforcements inside the hull of a sailing dinghy. The methodology proposed in this paper considers as a starting point the volume inside the hull and the deck completely filled with material and the result after the simulations is a free form shape of the sailboat reinforcements. The TO procedure is based on two different input FEM solutions: one is the result of a structural analysis on the boat loaded with real forces acting during navigation and the other one is the result of a modal analysis aimed to extract natural frequencies of the structure. The result must fulfil several requirements such as weight, stiffness and stress. TO models have been compared with a traditionally designed sailboat with the same total mass and relevant improvements have been obtained in terms of local stiffness and reduction of moments of inertia.

Investigations on the interface-dominated deformation mechanisms of two-dimensional MAX-phase Ti3Al(Cu)C2 nanoflakes reinforced copper matrix composites

Two-dimensional (2D) materials showing the giant advantage over their bulk counterparts are believed to be the ideal reinforcement for metal matrix composites, whereas the deformation mechanism of which is currently unknown. Herein, we investigated the interface effect of 2D MAX phase Ti3Al(Cu)C2 nanoflakes (MAX NFs) obtained by a Cu-atoms-diffusion assisted exfoliation method on the plastic deformation process of Cu matrix. Tensile tests demonstrated a simultaneous enhancement in strength and fracture elongation with the increase of MAX NFs content. The composites exhibited a four-stage deformation process involving an extended “yield plateau” before obvious strain hardening stage. Microstructural examination revealed that the 2D nature of MAX NFs and the coherent interface structure facilitated the nucleation of partial dislocations, which coordinated the initial plastic deformation by gliding and interacting to form Lommer-Cottrel (LC) locks. At high strain levels, both LC locks and MAX NFs served as obstacles for dislocation cross-slip and thus achieved significant forest hardening (or latent hardening) effect, validated by EBSD texture from the in-situ tensile tests and visco-plastic self-consistent simulation. This sort of interface-induced microstructure evolution promoted tortuous micro-cracks along discontinuous slip bands and significant crack bridging and deflection extrinsic toughening mechanisms. The current findings provide a possible strategy of simultaneously enhancing strength and ductility through tailoring 2D geometric shape of reinforcements and their interface with the metal matrix.

Studi Perilaku Balok Beton dengan Tulangan Bambu Laminasi Limbah Plastik

The method used in this study is an experimental method by conducting a series of tests ranging from bamboo preservation, bamboo lamination and aggregate testing. The design of concrete mix design uses the SK SNI 03-2834 - 2000 method. The dimensions of the beam used are 900 mm long, 100 mm wide, and 150 mm high. Variations in the shape of the bamboo reinforcement used are square and circle diameter of 10 mm.The results showed that the flexural strength produced by steel reinforcing concrete blocks was 842.4253 Kgm, square laminated bamboo reinforcement concrete blocks amounted to 546.7123 Kgm, and circular laminated bamboo reinforcement concrete blocks amounted to 536.5153 Kgm. The percentage of average flexural strength of laminated bamboo reinforcement is equivalent to 60% of steel reinforcement.

Stress–strain model for confined concrete in rectangular columns with corroded transverse reinforcement

Reinforcement corrosion and the configuration of transverse reinforcement have evident influences on the stress–strain relation of confined concrete in rectangular corroded columns, which are not properly considered by current stress–strain models. In this paper, the experimental results of 27 reinforced concrete (RC) rectangular columns with corroded transverse reinforcement were discussed, which revealed that key variables such as corrosion degrees have significant influences on the maximum stress and the corresponding axial strain of specimens. Based on test data and nonlinear regression analyses, empirical equations were proposed to account for the impacts of both reinforcement corrosion and the rectangular shape of transverse reinforcement on three important characteristic parameters of the stress–strain curves, namely the maximum strength, the axial strain at maximum strength and the ultimate strain of confined concrete. Comparisons revealed that the proposed stress–strain model outperformed existing models and demonstrated good agreement with test results.

Effect of reinforcement shape on the compression performance of ZTAp/40Cr three-dimensional interpenetrating network composites

The architectural design of the metal matrix composites can fully exploit their strength and toughness, and the experimental research has confirmed the development of the three-dimensional (3D) interpenetrating network as an essential approach for the design of the composite architecture. The traditional experimental method is incapable of meeting the needs for developing the architectural composites. The effect of the reinforcement shape on the compression performance of the 3D interpenetrating network composites was numerically analyzed in this study, using the finite element simulation method to model three types of reinforcement shapes (irregular polyhedral, regular 24-faceted body and solid sphere). The effect of the reinforcement shape on the macroscopic crack extension was compared. The influence of the reinforcement shape on the failure and fracture of the 3D interpenetrating network composites was obvious. Further, the bearing capacity of each phase of the 3D interpenetrating network configuration composites during uniaxial compression was investigated. The findings obtained in this study serve both as a theoretical and design foundation for gaining further insights into the performance of the 3D interpenetrating network composites.

Effect of FeTi-FeB inoculation on the shape of carbide reinforcements in hypoeutectic high chromium white cast iron

Abstract FeTi-FeB was added to molten high chromium white cast iron in amounts of 0.5–2.5 wt% at 50 °C above the melting temperature. The samples were produced in four groups. The first group samples were investigated as cast, the second group homogenized at 1000 °C for 1 h, and the other two groups were also homogenized at 1000 °C but for 3 and 6 h, respectively. To study the effect of FeB and FeTi on the microstructure, the samples were characterized by optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction and hardness tests. Wear tests were performed using a pin-on disc. A homogeneously dispersed carbide microstructure was produced by the homogenization heat treatment method. The addition of FeTi-FeB inoculants to high Cr white cast iron played an important role in the distribution of hard carbides. The chemical rate and the carbide volume varied on account of the added hard inoculant particles. TiB2, Cr3C2, M7C3, M23C6, and γ-FeCr phases formed on the surfaces. The hardness and wear resistance were improved considerably due to FeTi-B inoculation.

Performance of variously shaped glass-fibre-reinforced polymer bars in concrete columns

An investigation was carried out into the structural performance of concrete columns reinforced with various shapes of glass-fibre-reinforced polymer bars and stainless steel stirrups under concentric loading at ultimate limit state. Six square-section columns were cast to investigate the effects of different reinforcement types. The results showed failure modes depended on reinforcement material, shape and stirrup spacing. Across all specimens, steel-reinforced columns had higher loading capacity and better ductile performance, followed by L-shape and then round polymer bars. Smaller spiral spacing increased confinement efficiency and ductility and provided sufficient restraint against longitudinal polymer bar buckling. Finite-element models were also calibrated, and the results were in close agreement with experimental measurements. Based on the calibrated models, numerical parameters were studied to understand further the behaviour of composite columns reinforced with glass-fibre-reinforced polymer.