Abstract
An efficient and accurate classification method for failure modes of reinforced concrete (RC) columns was proposed based on key characteristic parameters. The weight coefficients of seven characteristic parameters for failure modes of RC columns were determined first based on the support vector machine-recursive feature elimination. Then key characteristic parameters for classifying flexure, flexure-shear and shear failure modes of RC columns were selected respectively. Subsequently, a support vector machine with key characteristic parameters (SVM-K) was proposed to classify three types of failure modes of RC columns. The optimal parameters of SVM-K were determined by using the ten-fold cross-validation and the grid-search algorithm based on 270 sets of available experimental data. Results indicate that the proposed SVM-K has high overall accuracy, recall and precision (e.g., accuracy>95%, recall>90%, precision>90%), which means that the proposed SVM-K has superior performance for classification of failure modes of RC columns. Based on the selected key characteristic parameters for different types of failure modes of RC columns, the accuracy of SVM-K is improved and the decision function of SVM-K is simplified by reducing the dimensions and number of support vectors.
Key Words
classification method; failure modes; key characteristic parameters; reinforced concrete columns; support vector machine
Address
Bo Yu: School of Civil Engineering and Architecture, Guangxi University, Nanning 530004, China; Key Laboratory of Engineering Disaster Prevention and Structural Safety of China Ministry of Education, China; Guangxi Key Laboratory of Disaster Prevention and Engineering Safety, Nanning 530004, China
Zecheng Yu: School of Civil Engineering and Architecture, Guangxi University, Nanning 530004, China
Qiming Li: Power China Central China Electric Power Engineering Co, Ltd., Zhengzhou 450007, China
Bing Li: School of Civil and Environmental Engineering, Nanyang Technological University, 639798, Singapore
Abstract
An experimental study is carried out to investigate the performance of the cutting tool regarding the insert wear, surface roughness, cutting forces, cutting power and material removal rate of three coated carbides GC2015 (TiCN-Al2O3-TiN), GC4215 (Al2O3-Ti(C,N)) and GC1015 (TiN) during the dry turning of AISI4140 steel. For this purpose, a Taguchi design (L9) was adopted for the planning of the experiments, the effects of cutting parameters on the surface roughness (Ra), tangential cutting force (Fz), the cutting power (Pc) and the material removal rate (MRR) were studied using analysis of variance (ANOVA), the response surface methodology (RSM) was used for mathematical modeling, with which linear mathematical models were developed for forecasting of Ra, Fz, Pc and MRR as a function of cutting parameters (Vc, f, and ap). Then, Multi-Objective Ant Lion Optimizer (MOALO) has been implemented for multi-objective optimization which allows manufacturers to enhance the production performances of the machined parts. Furthermore, in order to characterize and quantify the flank wear of the tested tools, some machining experiments were performed for 5 minutes of turning under a depth of 0.5 mm, a feed rate of 0.08 mm/rev, and a cutting speed of 350 m/min. The wear results led to a ratio (VB-GC4215/VB-GC2015) of 2.03 and (VB-GC1015/VB-GC2015) of 4.43, thus demonstrating the efficiency of the cutting insert GC2015. Moreover, SEM analysis shows the main wear mechanisms represented by abrasion, adhesion and chipping.
Key Words
AISI4140 steel, cutting force, flank wear, multiple objective ant lion optimizer, PVD/CVD/MTCVD coated carbides, rsm, surface roughness, turning
Address
Billel Hamadi: Advanced Technologies in Mechanical Production Research Laboratory (LRTAPM), Badji Mokhtar-Annaba University, P.O. Box 12, 23000 Annaba, Algeria
Mohamed Athmane Yallese: Mechanics and Structures Research Laboratory (LMS), May 8th 1945 University, P.O. Box 401, Guelma 24000, Algeria
Lakhdar Boulanouar: Advanced Technologies in Mechanical Production Research Laboratory (LRTAPM), Badji Mokhtar-Annaba University, P.O. Box 12, 23000 Annaba, Algeria
Mourad Nouioua, Abderazek Hammoudi: Mechanics Research Center (CRM), BP N73B, Freres Ferrad, Ain El Bey, 25021 Constantine, Algeria
Abstract
This paper investigates the artificial neural network (ANN) to predict the dimensionless parameters for contact pressures and contact lengths under the rigid punch, the initial separation loads, and the initial separation distances of a contact problem. The problem consisted of two elastic infinitely layers (EL) loaded by means of a rigid cylindrical punch and resting on a half-infinite plane (HP). Firstly, the problem was formulated and solved theoretically using the Theory of Elasticity (ET). Secondly, the contact problem was extended based on the ANN. External load, the radius of punch, layer heights, and material properties were created by giving examples of different values used at the training and test stages of ANN. Finally, the accuracy of the trained neural networks for the case was tested using 134 new data, generated via ET solutions to determine the best network model. ANN results were compared with ET results, and well agreements were achieved.
Key Words
artificial neural network, contact problem, theory of elasticity
Address
Ecren Uzun Yaylaci: Surmene Faculty of Marine Science, Karadeniz Technical University, 61530, Trabzon, Türkiye
Erdal Öner: Department of Civil Engineering, Bayburt University, 69010, Bayburt, Türkiye
Murat Yaylaci: Department of Civil Engineering, Recep Tayyip Erdogan University, 53100, Rize, Türkiye
Mehmet Emin Özdemir: Department of Civil Engineering, Cankiri Karatekin University, 18100, Çank
Abstract
This paper presents an experimental investigation into the effectiveness of using carbon fibre reinforced polymer (CFRP) and steel plates to repair damaged reinforced concrete (RC) beams with circular web openings at shear zones. It highlights the effectiveness of externally bonded CFRP and steel plates in repairing damaged RC beams by analysing the repaired beams' load capacity, deflection, strain, and failure mode. For the experiment, a total of five beams were used, with one solid beam as a control beam and the other four beams having an opening near the shear zone. Two beams with openings were repaired using inclined and vertical configuration CFRP plates, and the other two were repaired using inclined and vertical configuration steel plates. The results confirm the effectiveness of CFRP and steel plates for repairing damaged RC beams with circular openings. The CFRP and steel plates significantly increase ultimate capacity and reduce deflection under the openings. The inclined configuration of both CFRP and steel plates was more effective than the vertical configuration. Using an inclined configuration not only increases the ultimate capacity of the beams but also changes the mode of failure from shear to flexural.
Key Words
CFRP plate; circular web opening; RC beams; repair configuration; steel plate
Address
Moatasem M. Fayyadh: Asset Lifecycle, Sydney Water, 2150 NSW, Australia
Mohammed J. Abed: Department of Environmental Engineering, University of Tikrit, Sallahuddin, Iraq
Abstract
Major engineering requirements and technological developments in the steel construction industry are discussed to support a new innovative system, namely corrugated web beams, for future structural projections. These new-generation steel beams, fabricated as welded plate girders with corrugated webs, are designed to combine large spans with very low weight. In the present study, the flexural capacity of optimally designed trapezoidal and sinusoidal corrugated web beams was aimed at. For this purpose, the new metaheuristic methods, specifically hunting search and firefly algorithms, were used for the minimum weight design of both beams according to the rules of Eurocode EN 1193 15 and DASt-Ri 015. In addition, the strengthening effects of the corrugation geometry at the web posts on the load capacity of fabricated steel beams were tested in a reaction frame. The experimental tests displayed that the lateral capacity of trapezoidal web beams is more durable under flexural loads compared to sinusoidal web beams. These thin-walled beams were also simulated using a 3-D finite element model with plane strain to validate test results and describe the effectiveness of the ABAQUS software.
Key Words
corrugated web beams; finite element method; optimization; sinusoidal web beams; trapezoidal web beams
Address
Ferhat Erdal: Department of Civil Engineering, Akdeniz University, Antalya, Türkiye
Osman Tunca: Department of Civil Engineering, Karamanoglu Mehmetbey University, Karaman, Türkiye
Harun Taylan, Ramazan Ozcelik, Huseyin Sogut: Department of Civil Engineering, Akdeniz University, Antalya, Türkiye
Abstract
In the last ten years, many researchers have studied the vibrations of carbon nanotubes using different beam theories. The nano- and micro-scale systems have wavy shape and there is a demand for a powerful tool to mathematically model waviness of those systems. In accordance with the above mentioned lack for the modeling of the waviness of the curved tiny structure, a novel approach is employed by implementing the Timoshenko-beam model. Owing to the small size of the micro beam, these structures are very appropriate for designing small instruments. The vibrations of double walled carbon nanotubes (DWCNTs) are developed using the Timoshenko-beam model in conjunction with the wave propagation approach under support conditions to calculate the fundamental frequencies of DWCNTs. The frequency influence is observed with different parameters. Vibrations of the double walled carbon nanotubes are investigated in order to find their vibrational modes with frequencies. The
aspect ratios and half axial wave mode with small length are investigated. It is calculated that these frequencies and ratios are dependent upon the length scale and aspect ratio.
Address
Emad Ghandourah: Nuclear Engineering Department, Faculty of Engineering, King Abdulaziz University, Jeddah, Saudi Arabia
Muzamal Hussain: Department of Mathematics, Govt. College University Faisalabad, 38040, Faisalabad, Pakistan
Faisal Al Thobiani: Marine Engineering Department, Faculty of Maritime Studies, King Abdulaziz University, Jeddah, Saudi Arabia
Mohammed Hefni: Mining Engineering Department, Faculty of Engineering, King Abdulaziz University, Jeddah, Saudi Arabia
Sami Alghamdi: Electrical and Computer Engineering Department, King Abdulaziz University, Jeddah, Saudi Arabia; Center of Nanotechnology, King Abdulaziz University, Jeddah, Saudi Arabia
Abstract
The updated Turkish Building Earthquake Code has been significantly renovated and expanded compared to
previous seismic design codes. The use of earthquake ground motion levels with different probabilities of exceedance is one of the major advances in structural mechanics with the current code. This study aims to investigate the earthquake performance of steel structure in settlements with different seismic hazards for various earthquake ground motion levels. It is focused on earthquake and structural parameters for four different ground motion levels with different probabilities of exceedance calculated according to the location of the structure by the updated Turkish Hazard Map. For this purpose, each of the seven different geographical regions of Turkey which has the same seismic zone in the previous earthquake hazard map has been considered. Earthquake parameters, horizontal design elastic spectra obtained and comparisons were made for all different
ground motion levels for the seven different locations, respectively. Structural analyzes for a sample steel structure were carried out using pushover analysis by using the obtained design spectra. It has been determined that the different ground motion levels significantly affect the expected target displacements of the structure for performance criteria. It is noted that the different
locations of the same earthquake zone in the previous code with the same earthquake-building parameters show significant variations due to the micro zoning properties of the updated seismic design code. In addition, the main innovations of the updated code were discussed.
Key Words
design spectra; earthquake; probability of exceedance; site-specific; steel structure
Address
Ercan Işik: Department of Civil Engineering, Bitlis Eren University, TR-13000, Bitlis, Türkiye
İbrahim Baran Karaşin, Abdulhalim Karaşin: Department of Civil Engineering, Dicle University, TR-21100, Diyarbak
Abstract
It is widely known that axially loaded fiber-reinforced polymer (FRP) confined concrete presents significant and enhanced mechanical properties with reference to the unconfined concrete. Therefore, to predict the mechanical behavior of FRP-confined concrete two quantities-peak strength and ultimate strain are required. Despite the significant advances, the determination of the ultimate strain of FRP-confined concrete is one of the most challenging problems to be resolved. This is often attributed to our persistence in desiring the conventional methods as the sole technique to examine this phenomenon and
the complex nature of the ultimate strain of FRP-confined concrete. To bridge the research gap, this study adopted two machine learning (ML) techniques-artificial neural network (ANN) and Gaussian process regression (GPR)-to analyze observations obtained from 627 datasets of FRP-confined concrete circular and non-circular sections under axial loading test. Besides, the techniques are also used to predict the ultimate strain of FRP-confined concrete. Seven parameters namely width/diameter of the specimens, corner radius ratio, the strength of concrete, FRP elastic modulus, FRP thickness, FRP tensile rupture strain, and the axial strain of unconfined concrete-are the input parameters used to predict the ultimate strain of FRP-confined concrete. The results of the current study highlight the merit of using AI techniques in structural engineering applications given their extraordinary ability to comprehend multidimensional phenomena of FRP-confined concrete structures with ease, low computational cost, and high performance over the existing empirical models.
Key Words
artificial neural network, concrete, Gaussian process regression, prediction, ultimate strain
Address
Ibrahim A. Tijani: Applied Laboratory for Advanced Materials & Structures (ALAMS), School of Engineering, The University of British Columbia, Kelowna, BC, V1V 1V7, Canada
Abiodun I. Lawal: Department of Energy Resources Engineering, Inha University, Yong-Hyun Dong, Nam Ku, Incheon, Korea; Department of Mining Engineering, Federal University of Technology, Akure, Nigeria
S. Kwon: Department of Energy Resources Engineering, Inha University, Yong-Hyun Dong, Nam Ku, Incheon, Korea
Abstract
Steel plate shear walls (SPSWs) are commonly utilized to provide lateral stiffness in high-rise structures. The simplified model is frequently used instead of the fine-scale model in the design of buildings with SPSWs. To predict the lateral strength of steel plate shear walls with diagonal stiffeners (DS-SPSWs), a simplified model is presented, namely the cross bracestrip model (CBSM). The bearing capacity and internal forces of columns for DS-SPSWs are calculated. In addition, a modification coefficient is introduced to account for the shear action of the thin plate. The feasibility of the CBSM is validated by comparing the numerical results with theoretical and experimental results. The numerical results from the CBSM and finescale model, which represent the bearing capacity of the DS-SPSW with varied stiffened plate dimensions, are in good accord with the theoretical values. The difference in bearing capacity between the CBSM and the fine-scale model is less than 1.35%. The errors of the bearing capacity from the CBSM are less than 5.67% when compared to the test results of the DS-SPSW. Furthermore, the shear and axial forces of CBSM agree with the results of the fine-scale model and theoretical analysis. As a result, the CBSM, which reflects the contribution of diagonal stiffeners to the lateral resistance of the SPSW as well as the effects on the shear and axial forces of the columns, can significantly improve the design accuracy and efficiency of buildings with DS-SPSWs.
Address
Yuqing Yang, Zaigen Mu and Boli Zhu: School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China
Abstract
It has previously been proposed that the yield-line method of analysis for reinforced concrete slabs could be automated via the use of rigid finite elements, assuming all deformations occur along element edges. However, the solutions obtained using this approach can be observed to be highly sensitive to mesh topology. To address this, a revised formulation that incorporates modified yield criteria to account for the presence of non-zero shear forces at interfaces between elements is proposed. The resulting formulation remains simple, with linear programming (LP) still used to obtain solutions for problems
involving Johansen's square yield criteria. The results obtained are shown to agree well with literature solutions for various slab problems involving uniform loading and a range of geometries and boundary conditions.
Key Words
linear programming; slabs and plates; yield-line analysis
Address
H. Ahmed: Jacobs UK Limited, London, UK
M. Gilbert: Department of Civil and Structural Engineering, University of Sheffield, Sheffield, UK
