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Three-Dimensional nonlinear finite element modeling for Bond Performance of Ribbed Steel Bars in Concrete Under Lateral Tensions

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INTERNATIONAL JOURNAL OF CIVIL ENGINEERING 2020年第5A期18卷 595-617页

作者： Jiang, Tao Wu, Zhimin Huang, Le Ye, Hailong Dalian Univ Technol Lab Coastal & Offshore Engn 2 Linggong Rd Dalian Liaoning Peoples R China Univ Hong Kong Dept Civil Engn Pokfulam Hong Kong Peoples R China

Development of experimental studies in bond behavior between deformed bar and concrete under complex stress conditions in the last 2 decades is significantly affecting the concrete design specification. This article presents a rib-scale finite element model (FEM) to study the bond behavior of deformed bar in concrete under lateral tensions. In this model, detailed modeling including the reinforcing bar ribs and the concrete keys in contact region is realized with real geometric parameters. At the concrete-bar interface, surface-to-surface contacts with tie constraints are used and relative sliding or separation between contact surfaces are inhibited;adhesion between concrete and deformed bar is ignored. A user-defined subroutine named VUSDFLD in ABAQUS software was incorporated into the concrete damaged plasticity (CDP) model to acquire more accurate concrete constitutive relations. The FEM is calibrated using pullout test data from published papers. The simulation results show that all specimens failed in splitting mode. The lateral tension is an adverse factor on the bond property between steel bar and concrete, both the ultimate bond strength and the slip at the peak bond stress decrease with the increase of the lateral tensions. Comparison of computational simulation with the experimental data indicates that the proposed model gives a reasonable prediction of the bond stress-slip curves as well as the concrete crack patterns.

关键词： nonlinear finite element modeling Ribbed reinforcing bar Concrete User-defined subroutine Bond stress-slip relationship Lateral tensions

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Punching shear performance of reinforced concrete slab-to-steel column connections incorporating ECC and UHPECC

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ENGINEERING STRUCTURES 2025年 322卷

作者： Hamoda, Ahmed Abadel, Aref A. Ahmed, Mizan Wang, Vincent Vrcelj, Zora Liang, Qing Quan Kafrelsheikh Univ Fac Engn Dept Civil Engn Kafrelsheikh Egypt King Saud Univ Coll Engn Dept Civil Engn Riyadh 11421 Saudi Arabia Curtin Univ Ctr Infrastruct Monitoring & Protect Sch Civil & Mech Engn Kent St Bentley WA 6102 Australia Victoria Univ Coll Sport Hlth & Engn POB 14428 Melbourne Vic 8001 Australia

Unlike the conventional reinforced concrete (RC) slab-column connection, the punching shear generated at the RC slab-to-steel column connection may lead to brittle punching shear failure due to the small area around the steel column. Moreover, the unexpected moments arising from eccentric loading can also lead to the failure of the slab in punching shear mode. This paper proposes employing high-performance concrete (HPC) to fill the critical punching shear zone to improve the punching shear resistance of RC slabs to steel column joints. Experiments on eight RC slabs to steel column connections are reported. The test parameters under investigation are the type of HPC used to fill the critical punching shear zone, the distance (S) of the HPC zone measured from the flanges of the steel column and loading condition (concentric and eccentric). The types of HPC include engineered cementitious composite (ECC) and ultra-high performance ECC (UHPECC). The experimental results show that the proposed techniques can significantly improve the cracking load, elastic stiffness, energy absorption capacity, ductility, failure modes, and ultimate load of the slab-to-column connections. The ultimate load of the tested connections is increased by as much as 33 %, and 28 % for the slabs subjected to concentric and eccentric loading, respectively. However, the ultimate load and energy absorption capacity of the slab with UHPECC having a S value of 1d, where d is the effective depth are lower than those of the control slab. Three-dimensional nonlinear finite element models are developed to simulate the performance of tested slab-to-column connections and validated by experimental results. The parametric study shows that the n (=S/d) value greater than 3.5 has insignificant effects on the ultimate punching shear capacity of the slab. It is demonstrated that the proposed formulas faithfully estimate the ultimate punching shear capacity of slab-to-column connections constructed with differen

关键词： Punching shear High-performance concrete Engineered cementitious composite nonlinear finite element modeling

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Strengthening Reinforced Concrete Walls with Externally Bonded Galvanized Steel Sheets and Near-Surface Mounted Steel Bars

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BUILDINGS 2025年第4期15卷 636-636页

作者： Hamoda, Ahmed Bahrami, Alireza Abadel, Aref A. Ahmed, Mizan Ghalla, Mohamed Kafrelsheikh Univ Fac Engn Civil Engn Dept Kafrelsheikh 6860404 Egypt Univ Gavle Fac Engn & Sustainable Dev Dept Bldg Engn Energy Syst & Sustainabil Sci S-80176 Gavle Sweden King Saud Univ Coll Engn Dept Civil Engn Riyadh 11421 Saudi Arabia Curtin Univ Ctr Infrastruct Monitoring & Protect Sch Civil & Mech Engn Kent St Bentley WA 6102 Australia

Reinforced concrete (RC) walls are mainly used in RC structures to resist gravity and lateral forces. These structural elements may need to be upgraded to withstand additional forces and extend their life cycle. Therefore, it is crucial to provide effective strengthening techniques using low-cost sustainable materials under optimal conditions to rehabilitate RC walls. This study presents an experimental and numerical investigation of reinforced normal concrete (NC) walls strengthened with near-surface mounted (NSM) steel bars, confined with or without an externally bonded reinforced (EBR) galvanized steel sheets (GSSs). A total of six RC walls were constructed, loaded, and tested to failure. The examined parameters included the type of strengthening technique, materials used, and the position and configuration of the strengthening. Both EBR and NSM techniques were applied using GSSs and steel bars, respectively. The configurations were introduced in vertical and horizontal positions to resist gravity and lateral forces, respectively. The experiments revealed that these parameters significantly influenced the crack control, energy absorption, mode of collapse, and ultimate load capacity. nonlinear three-dimensional finite element models were developed and verified against experimental results, achieving a validation accuracy of 95% on average. This was followed by a parametric study investigating the effect of confinement with or without vertical reinforcements. Both experimental and numerical results confirmed that the strengthening could increase the ultimate load capacity from 20% to 38%.

关键词： reinforced concrete wall externally bonded reinforcement galvanized steel sheet nonlinear finite element modeling

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Numerical modeling of Squat Reinforced Concrete Shear Walls with High-Strength Materials

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ACI STRUCTURAL JOURNAL 2024年第5期121卷 175-188页

作者： Devine, Robert D. Barbachyn, Steven M. Kurama, Yahya C. Thrall, Ashley P. Univ Notre Dame Notre Dame IN 46556 USA Univ Minnesota Theodore V Galambos Struct Engn Lab Minneapolis MN USA Univ Minnesota Multiaxial Subassemblage Testing MAST Lab Minneapolis MN USA Univ Notre Dame Civil Engn Notre Dame IN USA Univ Notre Dame Struct Engn Notre Dame IN USA

This paper presents a numerical study that simulates the behavior of squat reinforced concrete (RC) shear walls with high-strength reinforcing steel and high-strength concrete. The finite element models are critically evaluated based on previous experiments of four deep-beam specimens and four squat shear-wall specimens with varied material strengths, base moment-to-shear ratios, and section shapes (rectangular and flanged). Monotonic lateral load analyses provided reasonable predictions of the peak lateral strength for squat walls tested under reversed-cyclic loading. However, reversed-cyclic models were necessary for more accurate predictions of the cyclic lateral load versus drift behavior, including cracking, stiffness degradation, lateral load-resistance mechanism, peak strength and corresponding drift, and energy dissipation. Importantly, the model predictions for specimens using high-strength materials were as good as or better than those using normal-strength materials with the same base moment-to-shear ratio. Thus, the use of higher-strength materials did not negatively impact the ability of the models to predict wall behavior.

关键词： deep beams high-strength concrete (HSC) high-strength steel reinforcement low aspect ratio nonlinear finite element modeling shear design shear walls stocky walls

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Computational investigation of bistable and non-bistable deployable scissor structures

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STRUCTURES 2024年 61卷

作者： Azorin, Rodrigo Gimenez Santana, Murillo V. B. Berke, Peter Z. Univ Libre Bruxelles ULB Bldg Architecture & Town Planning BATir Dept CP194-250 Ave Franklin Roosevelt B-1050 Brussels Belgium Aix Marseille Univ CNRS IUSTI F-13013 Marseille France

Deployable scissor structures can be classified as non-bistable and bistable (exhibiting snap-through) based on their transformation behavior. The question whether the advantage of bistable scissor structures of instantaneous serviceability upon deployment outweighs the disadvantages of their design and structural complexity is researched in this contribution through the application of design optimization to a lightweight emergency footbridge for non-bistable and bistable approaches. The originalities of the present work include the setup of a computational methodology coupling finite element simulations and structural optimization and a critical quantitative comparison of the two design strategies performed by defining and employing different performance indicators for varying structural parameters. The maximum footbridge span respecting weight (transportability) and deflection constraints is also derived for both designs. A total of 24 cases with varying spans and number of constituting modules is critically compared. It is shown that the non-bistable design is generally superior (lower weight and complexity) and dominant parameters influencing the performance indicators are identified.

关键词： Deployable scissor structures Bistability Structural optimization nonlinear finite element modeling Footbridge Structural complexity

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Marginal integrity in minimally invasive molar resin composite restorations: Impact of polymerization shrinkage

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JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS 2024年 155卷 106554页

作者： Weimann, Dominique Fleck, Claudia Razi, Hajar Tech Univ Berlin Mat Sci & Engn Berlin Germany Swiss Fed Inst Technol Zurich Switzerland Empa Cellulose & Wood Mat Lab WoodTec Grp Dubendorf Switzerland

Objectives: This study utilized non -linear finite element (FE) models to explore polymerization shrinkage and its impact on marginal integrity in molars following both selective caries removal (SCR) and conventional treatment. Specifically, we performed 2D in silico simulations to study residual stresses post -resin polymerization shrinkage and their influence on the marginal integrity of various restoration types. Methods: Initially, FE models were developed based on a cohesive zone framework to simulate crack propagation along the bonded interfaces between restoration and tooth structure in SCR-treated molars with class I and class II restorations. The modeled resin composite restorations first underwent polymerization shrinkage and were then subjected to various occlusal loading conditions. Stress magnitudes and distributions were identified to evaluate the margin integrity and predict the mechanism and location of interfacial failure. Results and discussion: The FE models computed polymerization shrinkage stresses of less than 1 MPa, exerting a minor influence on the composite/tooth interface. Occlusal loading, however, significantly impacted the loadbearing capacity of the composite/tooth (c/t) interface, potentially jeopardizing the restoration integrity. Especially under bi -axial occlusal loading, interfacial debonding occurred in the vertical cavity walls of the class I restorations, increasing the risk of failure. Notably, SCR-treated teeth exhibited better margin integrity than restored teeth after complete caries removal (NCR). These findings provide valuable insights into the mechanical behavior of SCR-treated teeth under different loading conditions and highlight the importance of considering the load scenarios that may lead to failure at the c/t interface. By investigating the factors influencing crack initiation and delamination, this novel research contributes to the optimization of restorative treatments and aids in the design of more resilient de

关键词： Selective caries removal Tooth-restoration marginal integrity Polymerization shrinkage Minimally invasive dentistry nonlinear finite element modeling Failure/crack modeling

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A comprehensive numerical study on examining the failure mechanisms of masonry walls via continuous micro modeling

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ENGINEERING FAILURE ANALYSIS 2025年 177卷

作者： Komurcu, Sedat Istanbul Tech Univ Dept Civil Engn TR-34469 Sariyer Istanbul Turkiye

modeling the failure mechanisms of masonry structures is one of the most challenging issues in structural engineering. This study presents nonlinear analysis to determine the failure mechanisms of masonry walls via continuous micro modeling. The stages of creating a continuous micromodel and applying a nonlinear material model and failure criteria to determine the failure mechanisms of masonry walls are presented. The study systematically and comprehensively examines the failure mechanisms of masonry walls via continuous micro modeling considering different structural scenarios such as dynamic effects and short column effect. Distributions of stresses, strains, occurred under cyclic loads for the masonry walls are determined in dynamic analysis. nonlinear finite element analyses on masonry walls are performed to investigate the effects of design parameters such as bond style and mortar thickness. nonlinear structural behavior of confined masonry walls having different infill ratio are analyzed and failure mechanisms of walls are investigated. It was seen that to determine the failure mechanisms of masonry walls, continuous micro modeling technique can be used efficiently in nonlinear structural analysis.

关键词： Confined masonry wall Continuous micro modeling Failure mechanisms Masonry design parameters nonlinear finite element modeling Short column effect

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An investigation into mechanical properties of jute-polyester laminates for numerical prediction of strength and failure

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POLYMER COMPOSITES 2021年第11期42卷 5975-5999页

作者： Karthika, Muthuthevar Ramamoorthy Deb, Anindya Venkatesh, Gude Subbaraya Indian Inst Sci CPDM Bangalore Karnataka India VTU PG Ctr Bangalore Karnataka India

The study of natural fiber-based composites, which are being seen as a potential eco-friendly alternative to popular synthetic fiber-reinforced composites, has, of late, gained considerable momentum. Replacing the latter composites is, however, an uphill task especially for advanced mechanical and structural engineering applications, which often require assessment of behaviors of materials and components numerically till failure. An implied scenario, for example, would be to design automotive body components using natural fiber-reinforced composites of sufficient strength for meeting crashworthiness requirements. In the current study, bi-directionally woven jute fabric, due to its established supply base and consistent quality, has been chosen along with a general purpose polyester resin for fabrication of laminates of high fiber volume fraction obtained by combining the hand layup method with compression molding. A detailed and comprehensive mechanical characterization includes, for the first time, determination of tensile, compressive, shear, and flexural behaviors of jute-polyester laminates in a single unified study. The consistency of the generated mechanical properties, including deployment of secant moduli instead of conventional initial tangent moduli, in a finite element constitutive model is established by predicting the test-based stress-strain or load-displacement behaviors and failure modes using a commercially available explicit nonlinear dynamic analysis code viz. LS-DYNA.

关键词： fiber volume fraction and density jute-polyester composite nonlinear finite element modeling tensile compression shear and flexural testing

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A sensor-enabled cloud-based computing platform for computational brain biomechanics

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COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2023年 233卷 107470-107470页

作者： Menghani, Ritika R. Das, Anil Kraft, Reuben H. Penn State Univ Dept Mech Engn University Pk PA 16802 USA Penn State Univ Dept Biomed Engn University Pk PA 16802 USA Penn State Univ Inst Computat & Data Sci University Pk PA 16802 USA 320 Leonhard Bldg University Pk PA 16802 USA

Background and Objectives: Driven by the risk of repetitive head trauma, sensors have been integrated into mouthguards to measure head impacts in contact sports and military activities. These wearable devices, referred to as "instrumented" or "smart" mouthguards are being actively developed by various research groups and organizations. These instrumented mouthguards provide an opportunity to further study and understand the brain biomechanics due to impact. In this study, we present a brain model-ing service that can use information from these sensors to predict brain injury metrics in an automated fashion. Methods: We have built a brain modeling platform using several of Amazon's Web Services (AWS) to enable cloud computing and scalability. We use a custom-built cloud-based finite element modeling code to compute the physics-based nonlinear response of the intracranial brain tissue and provide a frontend web application and an application programming interface for groups working on head impact sensor technology to include simulated injury predictions into their research pipeline. Results: The platform results have been validated against experimental data available in literature for brain-skull relative displacements, brain strains and intracranial pressure. The parallel processing capabil-ity of the platform has also been tested and verified. We also studied the accuracy of the custom head surfaces generated by Avatar 3D. Conclusion: We present a validated cloud-based computational brain modeling platform that uses sensor data as input for numerical brain models and outputs a quantitative description of brain tissue strains and injury metrics. The platform is expected to generate transparent, reproducible, and traceable brain computing results. (c) 2023 Published by Elsevier B.V.

关键词： Brain biomechanics Cloud computing nonlinear finite element modeling Integrated mouthguard sensors

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Dynamic Behavior of a Geotextile-Reinforced Pond Ash Embankment

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JOURNAL OF EARTHQUAKE ENGINEERING 2020年第11期24卷 1803-1828页

作者： Vijayasri, Thanikella Raychowdhury, Prishati Patra, Nihar Ranjan Indian Inst Sci Bangalore Dept Civil Engn Bangalore Karnataka India Indian Inst Technol Kanpur Dept Civil Engn Kanpur Uttar Pradesh India

The present study investigates the applicability of woven geotextile in improving the seismic performance of a pond ash embankment located in Renusagar, in seismic zone III of India. Reinforcing materials used are woven geotextiles, placed at 1 and 3 layers of pond ash embankment. To obtain the material models, strain-controlled cyclic triaxial tests had been carried out. A general expression was developed for shear modulus and damping ratio of pond ashes reinforced with and without woven geotextiles considering the data taken from seismic zones of III and IV. The proposed equations have been compared with the reported results of other pond ashes located in India. finite element model of the pond ash embankment reinforced with geotextiles has been developed. A fluid solid porous material model has been employed to incorporate pore pressure build up during cyclic loading. A parametric study has also been performed to study the effect of reinforcements on the seismic behavior of Renusagar pond ash embankment. Results showed that using the three layers of geotextile, the lateral displacement reduces up to 17%, and the excess pore pressure reduces as much as 30-45%. From the study, it can be concluded that use of woven geotextile in pond ash dykes can be beneficial for its application as reinforcing material in highway embankments, building fills, and earth dams.

关键词： Pond Ash Embankment Seismic Analysis nonlinear finite element modeling Ground Response Analysis Woven Geotextiles Liquefaction Potential

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