Open Engineering最新文献

{"title":"Effect of openings on simply supported reinforced concrete skew slabs using finite element method","authors":"Kaythar A. Ibrahim, S. Al-Darzi, M. H. Shukur","doi":"10.1515/eng-2022-0464","DOIUrl":"https://doi.org/10.1515/eng-2022-0464","url":null,"abstract":"Abstract Reinforced concrete skew slabs are commonly used in bridges due to space constraints in motorways and in congested urban areas. Such slabs also often need to contain openings for architectural requirements or services, and this study seeks to determine the effect of these openings on the strength of the skew slabs. The finite element method was used to analyze 13 cases of slabs with skew angles of 45°. The first and second cases were used to validate the results with experimental work. Other cases studied the effect of the position and shape of openings on the strength of the skew slabs under both one-point and four-point loading conditions. The study also showed that the worst location for the opening was near the obtuse corners since this is where most of the load is transferred. With respect to the shape of openings, three different shapes with the same area were used: skew, circle, and square shapes. It was found that the effect of the opening shape depends on how many steel reinforcements are removed, as well as the appearance of negative cracking brought on as a result of the opening. Overall, the square shape introduces the smallest reduction in the skew slab strength compared with a slab with no opening. Accordingly, the study recommends that the strength of skew slabs can best be maintained if square openings are employed near the acute corners, alongside negative steel reinforcement to avoid cracking.","PeriodicalId":19512,"journal":{"name":"Open Engineering","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47455753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design parameters and mechanical efficiency of jet wind turbine under high wind speed conditions","authors":"Abbas Waheed Dahham, Asylbek Zhumabekovich Kasenov, Mohammed Wahhab Aljibory, Mahmood Mohammed Hilal, Kairatolla Kayrollinovich Abishev, Mussina Zhanara Kereyovna, Nurbolat Sakenovich Sembayev, Hussein Waheed Dahham, Petr Olegovich Bykov, Adamov Abilmazhin Alirakhimovich","doi":"10.1515/eng-2022-0450","DOIUrl":"https://doi.org/10.1515/eng-2022-0450","url":null,"abstract":"Abstract Turbines are one of the most important means of producing clean energy, as they do not cause any negative emissions affecting the environment. Recently, the need to design turbines capable of facing strong winds has appeared because the currently designed turbines must be cut off in such circumstances. This study aims to find the best design parameters and investigate the efficiency of the jet turbine at high wind speed conditions. SolidWorks and MatLab are used to design and analyze small jet wind turbines. The design parameters were chosen to obtain the best efficiency. The turbine diameter is 0.5 m, and the short blade length helps withstand the generated stresses due to strong wind, especially fatigue stress, and resists bending. Blade pitch angle beta starts from 2° from the vertical axis at the hub and changes harmonically along the length to end at an angle of 88° at the blade’s tip to allow air to pass through and not form a wall. The blade number has chosen 15 blades, corresponding to the Betz limit, to obtain the maximum power coefficient. As a result, the assigned power was obtained at a wind speed of 28 m/s. At a lower wind speed, it will work with acceptable efficiency and more efficiently at higher speeds. Therefore, this turbine is suitable to use in such cases.","PeriodicalId":19512,"journal":{"name":"Open Engineering","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135401917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of varied waste concrete ratios on the mechanical properties of polymer concrete","authors":"Aliaa Rasheed, Shatha Sadiq, Aseel Shaaban","doi":"10.1515/eng-2022-0468","DOIUrl":"https://doi.org/10.1515/eng-2022-0468","url":null,"abstract":"Abstract Polymer concrete (PC) was developed at the end of the 1950s and gained popularity in the 1970s for precast parts, flimsy floor coverings, and repairs. Due to its superior performance over traditional Portland cement concrete, which offers many benefits, including mechanical properties, quick hardening, and durability. In this article, polymeric concrete was made using a mixture of sand and epoxy, and different proportions of sand were replaced with crushed concrete waste. This study found that the ideal ratio between resin and fine aggregate was 23% resin to 77% fine aggregate in terms of the total weight of the combination to get the best dispersion of fine aggregate. Waste concrete replaced 5, 10, 15, and 20% of aggregate in PC, respectively. It was further demonstrated that increased waste concrete aggregate content in PC increased the 28-day compressive strength by 7.7, 13.44, 16.8, and 18.97%, respectively; flexural strength increased by 16.68, 25.32, 37.16, and 47.71% at 28 days’ age; and direct tensile strength was higher than the reference mixture by values of 3.41, 17.21, 23.54, and 30.38% at 28 days age. The findings recommended using recycled fine aggregate on PC and suggested a 20% replacement ratio as an optimum percentage.","PeriodicalId":19512,"journal":{"name":"Open Engineering","volume":"99 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136207652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A comparative study to solve fractional initial value problems in discrete domain","authors":"Alaa Mohsin Abed, Hosein Jafari, Mohammed Sahib Mechee","doi":"10.1515/eng-2022-0480","DOIUrl":"https://doi.org/10.1515/eng-2022-0480","url":null,"abstract":"Abstract In this article, we used some methods to solve Riemann-type fractional difference equations. Firstly, we use a method that is a composite method based on the successive approximation method with the Sumudu transform. Secondly, we use a method that is a composite method that consists of the homotopic perturbation method with the Sumudu transform. It was found that the results obtained from these combined methods are identical when compared. We also provided theories and illustrative examples to support the research findings.","PeriodicalId":19512,"journal":{"name":"Open Engineering","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136302036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of nano chromium addition on the corrosion and erosion–corrosion behavior of cupronickel 70/30 alloy in seawater","authors":"Ayad Mohammed Nattah, Asia Mishaal Salim, Nawal Mohammed Dawood","doi":"10.1515/eng-2022-0491","DOIUrl":"https://doi.org/10.1515/eng-2022-0491","url":null,"abstract":"Abstract Cupronickel alloys have found widespread use in various applications such as heat exchangers, refrigeration systems, equipment, pumps, and pipes. However, the inherent structure of cupronickel alone may not be able to withstand certain aggressive environments effectively. To address this issue, the mechanical properties and corrosion resistance of cupronickel alloys can be enhanced by carefully selecting the appropriate alloying compositions. The addition of nano chromium (20 nm) has been proposed as a means of designing cupronickel alloys with improved performance. In the present study, corrosion and erosion–corrosion behaviors of cupronickel 70/30 alloys produced by the casting method without and with three different additions of nano Cr (1, 1.2, and 1.5 wt%) were investigated. The prepared specimens were subjected to electrochemical tests in 3.5 wt% sodium chloride solutions to evaluate their corrosion behavior. Additionally, an erosion–corrosion test was conducted at an impact angle of 90°, using a slurry solution containing 1 wt% SiO 2 sand in 3.5 wt% NaCl solution as the erodent. The specimens were comprehensively characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction techniques. The surfaces of the alloy specimens exhibited superficial attacks, but no pits were observed. Moreover, the surfaces developed a greenish coloration. The electrochemical tests conducted using saline solution revealed that the corrosivity of the cupronickel alloy with nano chromium addition varied from moderate to low, depending on the selected concentration. Despite undergoing corrosion in the saline environment, the modified cupronickel alloys demonstrated good resistance to this corrosive process. Therefore, they can be considered suitable for use in highly aggressive environments, such as in seawater capture systems. The erosion–corrosion test results indicated that the addition of nano chromium significantly enhanced the resistance of the specimens to erosion–corrosion. At 1.5 wt% Cr, the erosion–corrosion rate was reduced by 99.27%.","PeriodicalId":19512,"journal":{"name":"Open Engineering","volume":"239 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135212044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Discharge coefficient and energy dissipation on stepped weir","authors":"Samaa H. Hantoosh, M. Shamkhi","doi":"10.1515/eng-2022-0427","DOIUrl":"https://doi.org/10.1515/eng-2022-0427","url":null,"abstract":"Abstract High volumes of kinetic energy are generated as water is transported to the dam downstream. Stepped weir are some of the best in lowering the kinetic energy of a flow traveling downstream. In stepped weirs, the steps’ design can impact how much of the flow’s kinetic energy is transferred downstream. Because these weirs could dissipate more power, recently, pooled designs have been more common than smooth ones. Therefore, this work investigated the impact of sills at the ends-edge of the steps and discharge values on flow patterns, particularly energy dissipation. Seventy-five experiments were conducted and five models were used with a slope angle of 35° with different step dimensions, different numbers of steps (14, 10, 7, 5, and 3), and other discharges. Three-step configurations were used: flat, fully pooled, and zigzag pooled steps. The results indicated that increasing the number of steps increased the energy dissipation rate. In addition, an increase in the discharge leads to an increase in the discharge coefficient and thus decreases the energy dissipation rate. A coefficient of determination R 2 {R}^{2} gives a good agreement for the discharge coefficient (0.73).","PeriodicalId":19512,"journal":{"name":"Open Engineering","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45972162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A review of rutting in asphalt concrete pavement","authors":"A. Albayati","doi":"10.1515/eng-2022-0463","DOIUrl":"https://doi.org/10.1515/eng-2022-0463","url":null,"abstract":"Abstract Undoubtedly, rutting in asphalt concrete pavement is considered a major dilemma in terms of pavement performance and safety faced by road users as well as the road authorities. Rutting is a bowl-shaped depression in the wheel paths that develop gradually with the increasing number of load applications. Heavy axle loadings besides the high pavement summer temperature enhance the problem of rutting. According to the AASHTO design equation for flexible pavements, a 1.1 in rut depth will reduce the present serviceability index of relatively new pavement, having no other distress, from 4.2 to 2.5. With this amount of drop in serviceability, the entire life of the pavement in effect has been lost. Therefore, it is crucial to look at the mechanism, possible reasons, as well as techniques, to reduce the rutting in order to offer long service life and safe roadways. To this end, the need has been arising for this research which deals mainly with a thorough review of the existing literature to highlight some key points for the researchers and pavement engineers related to rutting mechanism, measurement, and criteria, both intrinsic (mixture variables) and extrinsic (traffic and temperature) contributory factors to rutting, material characterization, test methods, and prediction methodologies, as well as possible ways to minimize the rutting distress in asphalt concrete pavement. So far, this research attempts to bridge the gap in the literature that frequently only addresses a single aspect of rutting by providing an in-depth review of rutting in asphalt concrete and thereby offers a complete comprehensive understanding of this major distress type.","PeriodicalId":19512,"journal":{"name":"Open Engineering","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42602419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study of the behavior of reactive powder concrete RC deep beams by strengthening shear using near-surface mounted CFRP bars","authors":"A. A. Azeez, A. Jaafar, M. M. Yussof, A. A. Blash","doi":"10.1515/eng-2022-0433","DOIUrl":"https://doi.org/10.1515/eng-2022-0433","url":null,"abstract":"Abstract The applications of modern materials especially reactive powder concrete for improving concrete structures have been significantly growing in recent years. Great conduct properties creep, shrinkage, little permeability, ultra-high strength, and expanded safety against corrosion are the important features of Reactive Powder Concrete. In addition, the use of the Near-Surface Mounted technique in recent decades has helped strengthen and repair shears-reinforced concrete (RC) for deep beams using carbon fiber replacement reinforcing bars. The parameters studied in the present research investigated the impact of the maximum load, deflection, stress–strain curve of concrete, first shear crack, crack pattern, and crack width. Considering the aforesaid cause and objective, one specimen of Reactive Powder Concrete RC deep beams has a rectangular cross-section of 150 mm in width, 500 mm in depth, and a total length of 1.2 m. One control specimen was tested for comparison. In addition, 12 control specimens (cylinder and cubes) are used for experimental investigation on the mechanical properties of normal and Reactive Powder Concrete deep beams. Following the specimens’ processing, they were subjected to one concentrated load pressure test through a hydraulic jack. Moreover, six core drill specimens were taken from those deep beams to obtain the real mechanical properties of those beams, including maximum stress, modulus of elasticity, density, stress–strain curve, and Poisson’s ratio, after subjecting them to the pressure machine. Depending on the results, the ultimate strength, deflection, and first shear crack capacity for the specimens (RPCDB1P-4NSM & RPCDB1P-8NSM) have increased by (21, 25), (47, 27), and (133, 150)%, respectively, compared with (CDB1PC20). Moreover, the specimens above have reduced the first shear crack width by (9, 33.25)% respectively compared with (CDB1PC20) at 65% of the ultimate shear load.","PeriodicalId":19512,"journal":{"name":"Open Engineering","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45389950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estimation method of corrosion current density of RC elements","authors":"Faustyn Recha","doi":"10.1515/eng-2022-0430","DOIUrl":"https://doi.org/10.1515/eng-2022-0430","url":null,"abstract":"Abstract The work is theoretical with the use of analytical calculations, subsequently confirmed by a numerical method, in which an attempt was made to verify the method of estimating the corrosion current density based on the deflection of reinforced concrete (RC) elements affected by reinforcement corrosion. The focus was on the possibility of estimating the corrosion current intensity on the basis of external measurements of deflections of RC elements subjected to reinforcement corrosion. The method can be used as an element supporting the diagnosis of RC structures. The article presents an example of analytical and numerical deflection calculations, on the basis of which an attempt was made to estimate the corrosion current density. The obtained results were considered satisfactory, which is sent for further considerations, and above all for experimental verification of the proposed method. The analysis was based on the theoretical work of a simply supported beam, whose analytical results were verified using the finite element method. For the purposes of theoretical considerations, the impact of corrosion of the beam reinforcement was assumed in the form of a history of changes in the intensity of the corrosion current obtained in another research work. Finally, the obtained results confirmed the assumptions regarding the possibility of estimating the corrosion current density on the basis of the deflection of the analyzed beam.","PeriodicalId":19512,"journal":{"name":"Open Engineering","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48291169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Punching shear of reinforced concrete slabs bonded with reactive powder after exposure to fire","authors":"R. Atea, Hasanain M. Dheyab, Rasha A. Aljazaari","doi":"10.1515/eng-2022-0393","DOIUrl":"https://doi.org/10.1515/eng-2022-0393","url":null,"abstract":"Abstract Reactive powder concrete (RPC) is one of the most recent and significant advancements in the world of building. Due to its higher concrete characteristics, it has a common excessive benevolence happening in the globe at the moment, excessive ductility, shrinkage resistance, and corrosion and abrasion resistance. Investigated is the method for amending the RPC experimentally in punching shear slab action and the properties of construction material to investigate properties of volumetric ratios of steel fiber, and silicas fume, tensile steel ratio, the most important component for construction is reinforced concrete, which works well with other materials to create structures in any shape that is needed. In the present research, investigational work of RC slab with (1,000 × 1,000 × 60) mm dimensions was tested. This study aims to see how the relative volume of steel fibers (Vf) and silica fume content (Sf) affect the actions of RC slabs after being exposed to fire. It originated that a concrete mix containing 2% steel fibers improved the RPC slab's cracking and final punching shear. The existence of reactive powder increases fire resistance. This study's experiment aimed to see how reactive powder and Slab's ultimate punching shear strength were affected by replacement ratio. Whenever a fire is present. After fire exposure, the initial and subsequent stiffness of reinforced concrete slabs reduced considerably the temperature grew from 25 to 750°C.","PeriodicalId":19512,"journal":{"name":"Open Engineering","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49028465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}