Challenge journal of structural mechanics最新文献

{"title":"Fuzzy logic based prediction of retaining wall stability","authors":"Esra Aslı Çubukçu, Esra Uray, Vahdettin Demir","doi":"10.20528/cjsmec.2023.04.003","DOIUrl":"https://doi.org/10.20528/cjsmec.2023.04.003","url":null,"abstract":"In geotechnical engineering, retaining walls are widely employed to solve the problem of supporting horizontal loads occurring between two different soil levels. In the traditional retaining wall design, stability checks continue until a safe design is obtained according to selected wall dimensions and soil properties. This design method is a process that is time-consuming and based on trial and error. In this study, the stability control of the retaining wall, which is a complex engineering design, has been carried out with fuzzy logic methods. Adaptive network-based fuzzy inference systems (ANFISs) including Grid Partition (ANFIS-GP) and Substructive Clustering (ANFIS-SC) have been utilized as fuzzy logic methods. The sliding stability criterion of the cantilever retaining wall has been obtained by performing 1024 retaining wall designs which are created using different wall dimensions. Ninety percent and ten percent of the 1024 sliding safety factor values acquired through numerical analyses were respectively allocated to the training and testing phases. The prediction performances of the methods have been evaluated by considering the Root Mean Square Error (RMSE), Mean Absolute Error (MAE), and Coefficient of Determination (R²) obtained for the sliding safety factors during the training and testing stages. Upon juxtaposing the actual and anticipated sliding safety factors for a dataset comprising 1024 observations, it has become evident that the ANFIS-SC methodology outperforms the ANFIS-GP approach in terms of predictive accuracy. Furthermore, this analysis culminated in the determination that the application of fuzzy logic methods stands as an efficacious and dependable means for checking the stability criteria of retaining walls.","PeriodicalId":488266,"journal":{"name":"Challenge journal of structural mechanics","volume":" 22","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138995083","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":"Potential improvement of clinker sand in the mechanical high temperature and transport properties with GGBS-based prepacked geopolymer composite","authors":"Haluk Görkem Alcan, Bilge Aksu Alcan, Barış Bayrak, Abdulkadir Cüneyt Aydın","doi":"10.20528/cjsmec.2023.03.002","DOIUrl":"https://doi.org/10.20528/cjsmec.2023.03.002","url":null,"abstract":"In this study, a new generation prepacked geopolymer composite (PGC) material that can meet different needs was obtained by combining geopolymer concrete (GPC) and prepacked aggregate concrete (PAC) technology. In the production of PGC, 5-8 mm quartz aggregates were placed in molds and, geopolymer mortar was injected between these aggregates. Aluminosilicate based blast furnace slag (GBFS) was used as binding in geopolymer mortars; sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) was used as alkali activator. In addition, clinker aggregate in different proportions was used as fine aggregate (0–4 mm) in the production of mortar. Within the scope of the study, the physical, mechanical, permeability and high temperature resistance properties of PGC were investigated. The produced samples were cured at 30 and 60 °C for 6 and 8 hours. Hardened unit weights of PGC vary between 2342 and 2539 kg/m3, and sorptivity values vary between 0 and 0.04 kg/m2.min0.5. While the increase in curing temperature and curing time increases the hardened unit weight values, it decreased permeability values. While the increase of clinker aggregate in the mortar phase does not change the hardened unit weight, it significantly reduced permeability. When the PGC samples are cured at 30 °C, the compressive strengths are 20.38–39.03 MPa; when curing at 60 °C, the compressive strengths are 35.21–57.04 MPa. Flexural strengths, 2.35–6.96 MPa with 30 °C cure, achieved 4.27–9.93 MPa results with 60 °C curing. Increasing the curing time and curing temperature significantly increased the compressive and flexural strengths. The increase in the amount of clinker aggregate added to the mortar phase decreased the strength values. While the compressive strength values of PGC mixtures do not fall below 15 MPa after being exposed to 300 °C high temperature; after the application of 600 °C high temperature, it lost up to 70% of its strength. Increasing the curing time and curing temperature, increased the high temperature resistance. The increase in the amount of clinker aggregate in the mixtures, decreased the strength loss rate.","PeriodicalId":488266,"journal":{"name":"Challenge journal of structural mechanics","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135397056","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 dosage on the mechanical properties of epscrete","authors":"Mehmet Canbaz, Emir Günaltılı, Uğur Albayrak","doi":"10.20528/cjsmec.2023.03.001","DOIUrl":"https://doi.org/10.20528/cjsmec.2023.03.001","url":null,"abstract":"Epscrete, which is made by employing aggregate made of expanded polystyrene beads, is often used to make wall panels, block components, and insulating plates. For these products to have greater mechanical qualities, 400, 600, and 800 dose epscrete specimens were made in this research, which also considered the influence of cement quantity. The water-cement ratio was considered to be 0.5. In addition to the reference specimens, the same manufacture was carried out utilizing a 1% plasticizer admixture. Specimens were subjected to unit weight, ultrasonic pulse, water absorption, bending, and comprehension tests 7 and 28 days after production. The effects of the dose and plasticizer rate on the physical and mechanical properties of early and ultimate epscrete specimens were determined according to the unit weight, ultrasonic pulse velocity, water absorption rates, bending and compressive strength values. Increasing the dosage increased the ultrasonic pulse velocity, reduced water absorption by reducing the amount of gap and reduced water absorption, and increased compressive strength by approximately 65 % and bending strength by about 60 %. It has been determined that the mechanical and physical properties of epscrete are affected by dose and mixture ratios. By increasing the dosage, it has been seen that carrier light carrier blocks can be obtained.","PeriodicalId":488266,"journal":{"name":"Challenge journal of structural mechanics","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135397057","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":"Viscoelastic rod using the generalized finite difference method","authors":"Fuat Korkut, Turgut Tokdemir","doi":"10.20528/cjsmec.2023.03.004","DOIUrl":"https://doi.org/10.20528/cjsmec.2023.03.004","url":null,"abstract":"The finite difference method is quite extensively used to obtain the approximate solutions of many equations of mathematical physics. In this study, the precise algorithm in the time domain is combined with the generalized finite difference method to solve dynamic viscoelasticity problems. The numerical results obtained are satisfactory, and they are presented together with finite difference and finite element solutions.","PeriodicalId":488266,"journal":{"name":"Challenge journal of structural mechanics","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135397055","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":"Three-dimensional static analysis of reinforced concrete cantilever beam using MATLAB Partial Differential Equation Toolbox","authors":"Olgun Köksal, Zeki Karaca, Erdem Türkeli","doi":"10.20528/cjsmec.2023.03.003","DOIUrl":"https://doi.org/10.20528/cjsmec.2023.03.003","url":null,"abstract":"Nowadays, three-dimensional (3D) solid model of the structures can be prepared by using computer aided design programs. There are many numerical methods for static, dynamic and temperature analysis of structural systems. The most preferred among these methods is the finite element method (FEM). In this method, the structural model with different geometry and boundary conditions should be solved by utilizing partial differential equations. Due to the long solution time while performing, finite element programs require computers with very good features. Therefore, analyses with desired features can be performed by using open source programs to shorten the duration of analysis. In this study, specifically, the static analysis of the selected reinforced concrete (RC) cantilever beam was carried out by using the open source MATLAB partial differential toolbox based on the FEM. Since the program used is open source, different concrete classes and finite element models were selected for the cited cantilever beam and static analyses were performed. As a result of the MATLAB partial differential toolbox analyses, the displacement, stress and deformation of the cantilever beam were obtained in 3D and compared with the ones obtained from ANSYS computer program.","PeriodicalId":488266,"journal":{"name":"Challenge journal of structural mechanics","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135397059","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}