Reinforcement Elements Research Articles

Sedir Ağacının (Cedrus libani) Farklı Kısımlarından Üretilmiş Alçı Esaslı Levhaların Özellikleri. 1. Bölüm. Fiziksel ve Mekanik Özellikler

In this study, it was found that the addition of wood had a reducing effect on water absorption (WA) and thickness swelling (TS) properties in gypsum-based boards. The lowest WA value of 41.56% was found sample prepared with cedrus’s bark/needle mixture (KaI3; 3:2 by weight). It has also been realized that experimental boards made only bark-gypsum (SKa6), cone-gypsum (SKo6) and needle-gypsum (SI6) proportions show Thickness Swelling (TS) values of 33.70%, 21.70% and 18.85%, respectively. However, the surface hardness (Shore D) has usually correlated with wood content but natural weathering negatively effects hardness that lowering from -6.9% (SKa1) to -30.3% (SKa2) in all typse experimental boards. It was found that panels produced with cedrus wood/cone (SKo); cedrus wood/needle (SI) and cedrus cone/needle (KoI) proportions have no higher values than standard Internal Bond (IB) value of 0.28 N/mm2. But the highest IB value of 0.48 N/mm2 was observed for a sample of SKa5 that produced with a ratio of 1:4 by cedrus wood/bark proportions (w/w). Moreover, the highest bending strength (MOR) values of 1.32 N/mm2 were calculated with SKa2 sample that produced with ratio of 4:1 by cedrus wood/bark proportions (w/w). These mechanical properties are probably related to experimental board manufacturing process, which consists of multi stage processing (slushing, soaking, formation, pressing and drying) may effect hindering reinforcement elements to develop the network matrix strength properly.

Vertical Fiberglass Micropiles as Soil-Reinforcing Elements.

This article is dedicated to developing a ground improvement technique using vertically oriented reinforcement elements prefabricated utilizing fiberglass pultruded pipe and helical shape wideners at the bottom toe. Structures of the prefabricated helical micropiles varied by the length and cross-section area introduced into the soil massive as reinforcing bearing elements. The effect of the reinforcements geometry variation was investigated through a reinforcement factor (µ), based on which a calculation method for measuring settlement of reinforced soil has been previously developed Full-scale field plate load tests were performed before and after reinforcing the soil to investigate the changes in the soil stiffness after the reinforcement process. Comparative analysis between the reinforced and reference soft sandy soil indicates an average increase in the deformation properties of the fiber reinforced soils by 8%, 30%, 63% at the applied pressures of 100, 300, and 550 kPa, respectively. The influence of the fiber reinforced polymers (FRP) geometrical properties on the final composite settlement was determined. A comparative analysis of the calculated and the actual plate load tests results reveals that the previously proposed settlement calculation method is adequate for further development.

Response of a model footing reinforced by novel three-dimensional elements

In this study, a new three-dimensional (3D) reinforcement element, comprising a horizontal ring connected to vertical legs, is introduced. A series of 1g laboratory-scale tests was conducted on a circular footing that rested on a sand bed containing planar or new 3D reinforcements. The effects of depth of the first layer, reinforcement configuration number and spacing of layers are reported. Tests were performed on discrete or contiguously attached elements. The new 3D elements were examined with either upward- or downward-facing legs. An improvement of about 16% was achieved by the upward-legged contiguous 3D elements over the performance delivered by planar contiguous elements. Also, the results show that the vertical legs are capable of exerting passive forces on the soil and increasing the stiffness and bearing capacity of the composite system, but the contributory effect is more pronounced for the upward-leg configuration. Finally, 17 and 26% improvements were achieved, respectively, for two planar and two 3D-reinforcement layers when compared with that of a single layer. The concept of planar reinforcement connected to vertical legs, could be adapted for developing a more efficient generation of reinforcement, such as geogrids with vertical ‘legs’, to take advantage of the passive resistance generated by ‘legs’.

АВТОМАТИЗАЦИЯ АРМИРОВАНИЯ ЖЕЛЕЗОБЕТОННЫХ ЭЛЕМЕНТОВ (ВОДОВОДОВ)

This work is devoted to the development of a script to reduce the time of reinforcement elements based on the use of an automation algorithm developed in the Dynamo environment. Thus, the purpose of the work is to solve the problem of automating the process of reinforcing reinforced concrete pipes in the Autodesk Revit software package using the Dynamo add-on. The developed algorithm has been tested in the reinforcement of several types of pipes. To adjust the algorithm, the existing norms for the reinforcement of reinforced concrete pipes are determined and taken as a basis. The presented approach can be optimized and used in the reinforcement of water conduits of technically complex objects, for example, hydraulic structures.

Mechanical behavior of entangled metallic wire materials-polyurethane interpenetrating composites

Composite materials exhibit the impressive mechanical properties of high damping and stiffness, which cannot be attained by employing conventional single materials. Along these lines, a novel material architecture is presented in this work in order to fabricate composites with enhanced mechanical characteristics. More specifically, entangled metallic wire materials were used as the active matrix, whereas polyurethane was employed as the reinforcement elements. As a result, an entangled metallic wire material-polyurethane composite with high damping and stiffness was prepared by enforcing the vacuum infiltration method. On top of that, the mechanical properties (loss factor, energy consumption, and average stiffness) of the proposed composite materials were characterized by performing dynamic tests, and its fatigue characteristics were verified by the micro-interface bonding, as well as the macro-damage factor. The impact of the density, preloading spacing, loading amplitude, and exciting frequency on the mechanical properties of the composites were also thoroughly analyzed. The extracted results indicate that the mechanical properties of the composites were significantly enhanced than those of the pure materials due to the introduction of interface friction. Moreover, the average stiffness of the composites was about 10 times the respective value of the entangled metallic wire material. Interestingly, a rise in the loading period leads to some failure between the composite interfaces, which reduces the stiffness property but enhances the damping dissipation properties. Finally, a comprehensive dynamic mechanical model of the composites was established, while it was experimentally verified. The proposed composites possess higher damping features, i.e., stiffness characteristics, and maintain better fatigue characteristics, which can broaden the application range of the composites. In addition, we provide a theoretical and experimental framework for the research and applications in the field of metal matrix composites.

Delamination of an Element of Reinforcement of the Half Plane Under Cyclic Loading

Delamination of an Element of Reinforcement of the Half Plane Under Cyclic Loading

Study of the Mechanical Properties of Polymer Composites Based on Polyolefins with the Addition of Rice Husk and Compatibilizer

The present work studies the mechanical behavior of rice husk as a reinforcement element in mixtures of polyolefins. The composites were made by polyolefin mixtures of 30% LDPE, 40% HDPE and 30% PP, rice husk and Polybond as a compatibilizer. Samples for the tensile test were prepared by injection and compressive methods. The results confirm that rice husk alongside the compatibilizer bring about positively in the strength of composites. In reference to the adherence of rice husk to the mixture of polyolefins, which was studied from the microstructure of composites, the addition of compatibilizer improves the adherence between the polyolefins and rice husk, and thereby the quality in the fracture surface. These composites are considered to be a good alternative for the recovery of plastic agricultural waste.

Interlayer Reinforcement in Shotcrete-3D-Printing

Additive manufacturing with cement-based materials has recently become increasingly common on construction site. The high degree of freedom in individual geometric shapes, the associated potential for resource-efficient designs, and the high degree of automation could make this technology a milestone in the history of construction industry. Many of the existing manufacturing techniques are initially based on unreinforced concrete. However, for many structural elements, the use of reinforcement is indispensable and therefore the reinforcement integration represents a prerequisite. One promising reinforcement strategy is the use of interlayer reinforcement. This method specifically uses the layered characteristic of the additive manufacturing process by integrating reinforcement between the applied layers. In combination with an adaptive path planning, it is therefore possible to manufacture force-flow-compliant reinforced elements with a minimal increase in process complexity compared to an unreinforced production. However, besides the integration process itself, material-process interactions represent an important research topic. Especially for Shotcrete-3D-Printing, the use of accelerators can significantly change the structural build-up of the applied material and thus effect the bonding ability of the sprayed concrete to the integrated reinforcement element. The present study investigates the effect of accelerator dosage on the bond properties of integrated rebars. The resulting bond is analyzed non-destructively via computed tomography and mechanically by pull-out tests according to RILEM RC6. The results show that the material compaction caused by the sprayed application leads to excellent bond properties. However, by using high accelerator dosages, bond deteriorations can be observed.

Reconstruction of Industrial Buildings with Replacement of Floors with Wood-Composite

The article emphasizes the importance of involving unused construction objects in the economy, while preserving their historical value. A variant of the reconstruction of floors based on tree-composite beams is proposed. The design work was carried out and the optimal variant of the work was identified. The relevance of this topic is due to the fact that the problem has a global scale, in most cases they are trying to solve it by demolishing a cultural heritage object, or replacing wooden floors with reinforced concrete or metal structures. The purpose of the published work is to propose an option for the possible return of functionality to construction objects while preserving them as a cultural heritage, using new wooden bending elements with elements of composite reinforcement.

Nonlinear supersonic post-flutter response of two-bay composite laminate curved panels

Aeronautical external structures are typically composed of multiple curved panels connected by reinforcement elements that allow structural interaction between the bays. In this context, the present study performs a numerical investigation on the nonlinear aeroelastic behavior of multibay composite laminate curved panels exposed to cross-stream supersonic flow. The post-flutter behavior of thin cylindrical shallow shells with H/h=1 and H/h=2 curvature ratios is examined for symmetric and asymmetric cross-ply laminates. Different from the majority of the studies, the nonlinear panel flutter assessment was not exclusively based on oscillation amplitudes but also energy quantification. Results have shown that the interaction between adjacent bays leads the system to a more complex behavior with higher energetic LCO compared to the widely used single panel approach. Additionally, the mechanical energy discretization concerning the fluttering two-bay panel arrangement exhibited how each bay operates with remarkably distinctive amounts of mechanical energy, which may be used as a direction in the design of active and passive control techniques for flutter suppression.

Evaluation of Mechanical Properties in Concrete Structure Reinforced with Carbon Fiber Coating

In this study, it was possible to evidence the efficiency of the use of carbon fiber coating in concrete structures and its application to promote the protection and maintenance of these materials, seeking to prolong the useful life of this type of structure. From mechanical tests, such as compressive strength, it was possible to observe an increase of 37% in the breaking load, as well as an increase of about 40% in compressive strength, when compared to tests with pure concrete. Therefore, the results pointed to the optimization of the mechanical properties of the structure, coated with carbon fiber and cured with epoxy resin. In other words, the use of this external load combined with epoxy resin was an important element in concrete reconstruction and reinforcement. Another interesting point was the issue of the high fiber rigidity observed in the AFM, allowing an excellent interaction with the resin in the coating of the specimen. The study showed that this type of coating can be used for the recovery of structures, as well as a reinforcement element, since many projects have difficulties with the high maintenance cost, as well as the daily monitoring of concrete structures.

Role of numerical modelling choices on the structural response of onshore wind turbine shallow foundations

Structural modelling of wind turbine shallow foundations on granular soil strata deals with combined complex phenomena, such as soil-structure interaction, material nonlinearities, local stress concentration in both reinforced concrete foundation and soil. Numerical finite element analyses are performed employing three-dimensional elements for both concrete foundation and soil and one-dimensional elements for reinforcement. The results of the nonlinear static simulations are validated with experimental results of recent tests carried out on 1:15 scaled models having reinforcement ratios and stress conditions similar to the prototype foundations designed according to current codes. The validated modelling strategies are also applied to investigate the role of nonlinearities in both soil and concrete foundation, emphasizing the parameters and the nonlinear constitutive laws that significantly affect the foundation response. Three different reinforcement layouts are considered in both testing and simulations of the prototype: (a) complete prototype reinforcement, (b) prototype without shear reinforcement and (c) prototype without shear reinforcement and with 50% of remaining reinforcement replaced by steel fibres. A critical comparison is also made with models employing elastic two-dimensional shell finite elements lying over elastic supports, typically adopted for design purposes.

A review on the application of industrial waste as reinforced earth fills in mechanically stabilized earth retaining walls.

The infrastructure development of a country is focussed on the development of roadways that includes the construction of many bridges and flyovers with retaining walls. The construction of the mechanically stabilized earth (MSE) retaining wall gained momentum since 1960 owing to the various beneficial aspects in terms of its durability, economy, stability, appearance, sustainability aspects, etc. A typical MSE retaining wall is a composite structure made up of compacted backfill and reinforcement elements, fixed to a wall facing. The increasing rate of urbanization leads to the development of more industries resulting in the production of wastes such as fly ash, waste foundry sand, pond ash, slags, etc. The disposal of these wastes is often a big issue for the industries, and hence, their utilization in the construction industry is studied by researchers to solve the problem of waste dumping. This review article summarizes the studies involving the potential use of industrial waste material as reinforced earth fills in the MSE retaining wall. The researchers used waste materials from industries like thermal power plant, mining, construction, metal smelting units etc. The important fill properties such as particle size, friction angle, and density were compared with the standard codal provisions. The different dimensions of the research experiments involving the MSE backfill using various industrial wastes were presented in this review.

Examination of the Use of Sculpture in the Open-Green Areas of Selçuk University Alaeddin Keykubat Campus

The sculpture, which is the expression of beliefs and fears in prehistoric times, has taken on different roles as an urban reinforcement element in all cultures with numerous themes. In the Middle Ages, it became an organic part of the architectural structure, teaching the truth about religious beliefs. With the Renaissance movement, it became independent by breaking away from the architectural structure and moved to the urban space. In the twenty-first century, its dimensions have grown to be equivalent to architecture, it has created its own space and established new aesthetic and functional relations with the audience. In this study, the relationship of some sculptures on the Alaeddin Keykubat campus of Selcuk University with the landscape elements was examined in terms of design elements and basic design principles. In the light of the data obtained, suggestions have been developed in order to increase the life and aesthetic quality of the campus.

Designing and Explanation of Reinforcement of Operated High Fills with the Injection of Solidifying Solutions

Stability loss of slopes of the operated high fills is associated with a complex of adverse factors. Formation of glide lines under loss of stability is of the probabilistic nature and depends on the soil physical and mechanical properties as well as on the weakened zones location. Loss of stability of the slope parts of the fill can occur according to various scenarios, for each of which its own reinforcement zones location is possible. Therefore, in order to assess the reinforcement zones of high fills and to further determine the optimal reinforcement schemes, three structural designs of high fills are considered, which model various scenarios of the stability loss. Numerical modeling allowed us to assess the stress-strain state of the high fill in operation and to identify the most adverse zones in the subgrade body that are of high priority for reinforcement – locations of weak zones. Assessment of reinforcement zones of the high fills in operation alongside with identification of their locations as well as evaluation of the nature of the stress-strain state are made based on the results of modeling the deformations and the stability loss of the high fill according to the revealed effects of the loads heavy impact with the application of the finite element method. Models of the operated high fills strengthened by reinforcement with the injection of solidifying solutions are theoretically substantiated and developed. For each model, an element-by-element description is performed and its application conditions are justified. Reinforcement elements in the models are selected with due regard to peculiarities of the stress-strain state in the zones which need reinforcement. Modeling the operation of the reinforced exploited high fills is carried out according to modern approaches to the mechanics description of the anisotropic medium that is represented by the soil mass which contains its reinforcing elements.

Ensuring the operational suitability of buildings, railways and bridges in of the Arctic zone in conditions of global warming

The effect of global warming, the trend of which in the western part of the Russian permafrost zone will be at least 2оС / 50 years is in the focus of the article. The main purpose of this study is to prevent the thawing of the permafrost base of buildings and structures of the transport infrastructure. It requires provision for strengthening the bases and foundations of objects erected according to principle I. The article provides an analysis of various reinforcement options. The elements of reinforcement (thermalstabilizers, injection wells) are shown to introduce significant thermal and deformation disturbances into the base, which requires a correct calculation justification of the reinforcement project.

A Two-Level Homogenization Approach for Polymer Nanocomposites with Coated Inclusions

In polymer nanocomposites, other than the matrix and inclusion, a third phase so-called interphase, is commonly observed. Inter-phase properties affect the overall macroscopic mechanical behavior. It is crucial to model the interphase and obtain the effective composite properties accordingly. Homogenization theory is very useful and powerful; however, many of the homogenization-based techniques have deficiencies. The goal of the study is to combine two very well-known homogenization techniques to model the polymer nanocomposites with coated inclusions. One of the goals of the study is to demonstrate the deficiency that originated from the interphase modeling and overcome this problem by the proposed two-level homogenization method. This method aims to model load transfer between the matrix and the reinforcement element through the interphase in a correctly. For this purpose, first, an effective inclusion is formed using finite element homogenization, then the effective inclusion and the matrix are homogenized using micromechanics-based Double Inclusion method. The proposed method provides a remarkable improvement compared to the micromechanics-based method for the soft interphase case.

Experimental investigations on tensile and flexural properties of epoxy resin matrix waste marble dust and tamarind shell particles reinforced bio-composites

A great gain has been made in recent years in the creation of hybrid bio-composites by combining different natural resources as reinforcement and filler elements. The waste marble dust particles and tamarind shell powder particles were additional to the epoxy resin matrix in this experiment to study the tensile and flexural characteristics of the epoxy resin matrix. Tamarind shell powder and waste marble dust particles are used as reinforcing materials. To create hybrid bio-composite specimens, researchers varied the reinforcement material weight percentages while maintaining the epoxy resin weight percentage as constant. Hot injection moulding was used to create hybrid biocomposites boards. The hybrid bio-composite specimens for tensile and flexural tests are cut away from the hybrid bio-composite boards using the water jet machining method as per ASTM specifications. Research shows that adding small amounts of fine waste marble dust particles and tamarind shell powder to an epoxy resin matrix enhances the hybrid bio-composites' tensile and flexural capabilities significantly. The maximum tensile strength, yield strength, elongation percentage, flexural strength and flexural modulus of 34.63 MPa, 32.81 MPa, 3.3 %, 36.17 and 38.53 MPa were obtained from 35 wt% tamarind shell powder and 15 wt% waste marble dust powder composite specimens (C4 Composites) correspondingly.

Fabrication of Al-Zr -Mg-Ni matrix composite with TiC reinforcement by multi-pass recursive friction stir processing and its characterization

A titanium carbide (TiC)-reinforced Al-Zr-Mg-Ni matrix was utilized for conjunction with multi-pass friction stir processing to create the composite. Reverse engineering and geometric reconstruction techniques were employed to produce a spherical channel at a prearranged depth from the area using wire-EDM and filled with reinforcement elements to prevent the spread of reinforcement particles during fabrication. Multiple recursive passes during friction stir processing were studied to determine the effects on particle distribution and crystallographic texture, as well as surface roughness and mechanical properties. The results showed that increasing the number of passes significantly improved particle distribution and reduced defects such as particle agglomeration and voids. After six passes, the grain size was condensed to 2.40 nm while the dislocation density increased due to the uniform distribution of TiC particles. Grain refinement led to a significant increase in the texture index, which resulted in a surface roughness of 153.593 nm. After six passes, the composite's hardness and tensile strength had increased due to the even distribution of TiC particles and various strengthening mechanisms.

Experimental investigations on flexural and compressive properties of epoxy resin matrix sugarcane fiber and tamarind seed powder reinforced bio-composites

Hybrid bio-composites have been developed in recent years by incorporating various natural resources as reinforcement and filler components to achieve the desired qualities. Experiments were conducted in this study to investigate the impact of short sugarcane fibres and tamarind seed powder particles on epoxy resin matrix flexural and compressive characteristics. Reinforcement elements include sugarcane fibres and tamarind seed powder particles. Samples of hybrid bio-composite material were created by altering the proportion of reinforcing components and maintaining the same proportion of the epoxy resin. A hot injection moulding machine was used to create hybrid bio-composite boards. With the use of a water jet machining technique, hybrid bio-composite specimens for flexural and compression testing are cut away from the hybrid bio-composite boards. The maximum flexural strength, flexural modulus and compressive strength of 36.543 MPa, 12.129 GPa and 21.32 MPa was obtained for 35 wt% SCF/15 wt% TSP composites correspondingly. The minimum flexural strength, flexural modulus and compressive strength of 25.058 MPa, 5.828 GPa and 14.21 MPa was obtained for 40 wt% SCF and 10 wt% TSP composites correspondingly. For the hybrid bio-composites, restricted insertion of short sugarcane fibre and tamarind seed powder particles into epoxy resin matrix greatly improves certain flexural and compressive performances.