Mohammed Sid Ahmed Houari, Aicha Bessaim, Tarek Merzouki, Ahmed Amine Daikh, Aman Garg, Abdelouahed Tounsi, Mohamed A. Eltaher and Mohamed-Ouejdi Belarbi
Abstract
This article introduces a novel analytical model for examining the impact of porosity on shear correction factors
(SCFs) in functionally graded porous beams (FGPB). The study employs uneven and logarithmic-uneven modified porositydependent power-law functions, which are distributed throughout the thickness of the FGP beams. Additionally, a modified exponential-power law function is used to estimate the effective mechanical properties of functionally graded porous beams. The correction factor plays a crucial role in this analysis as it appears as a coefficient in the expression for the transverse shear stress resultant. It compensates for the assumption that the shear strain is uniform across the depth of the cross-section. By applying the energy equivalence principle, a general expression for static SCFs in FGPBs is derived. The resulting expression aligns with the findings obtained from Reissner's analysis, particularly when transitioning from the two-dimensional case (plate) to the onedimensional case (beam). The article presents a convenient algebraic form of the solution and provides new case studies to demonstrate the practicality of the proposed formulation. Numerical results are also presented to illustrate the influence of porosity distribution on SCFs for different types of FGPBs. Furthermore, the article validates the numerical consistency of the mechanical property changes in FG beams without porosity and the SCF by comparing them with available results.
Key Words
functionally graded beam; modified exponential-power law function; porosity; shear correction factor; transverse shear
Address
Mohammed Sid Ahmed Houari: Laboratoire d'Etude des Structures et de Mécanique des Matériaux, Département de Génie Civil, Faculté des Sciences et de la Technologie, Université Mustapha Stambouli, Mascara, Algérie
Aicha Bessaim: Laboratoire d'Etude des Structures et de Mécanique des Matériaux, Département de Génie Civil, Faculté des Sciences et de la Technologie, Université Mustapha Stambouli, Mascara, Algérie
Tarek Merzouki: LISV, University of Versailles Saint-Quentin, 10-12 Avenue de l'Europe, 78140 V'elizy, France
Ahmed Amine Daikh: Département de Génie Civil, Faculté des Sciences et de la Technologie, Université Mustapha Stambouli, Mascara, Algérie; Department of Technology, University Centre of Naama, P.O.Box 66, 45000 Naama, Algeria
Aman Garg: State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
Abdelouahed Tounsi: YFL (Yonsei Frontier Lab), Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea; Material and Hydrology Laboratory, Faculty of Technology, Civil Engineering Department, University of Sidi Bel Abbes,
Sidi Bel Abbes, Algeria
Mohamed A. Eltaher: Mechanical Engineering Department, Faculty of Engineering, King Abdulaziz University, P.O. Box 80204, Jeddah 21589, Saudi Arabia; Mechanical Design & Production Department, Faculty of Engineering, Zagazig University, P.O. Box 44519, Zagazig 44519, Egypt
Mohamed-Ouejdi Belarbi: Laboratoire de Recherche en Génie Civil, LRGC, Université de Biskra, B.P. 145, R.P. 07000, Biskra, Algeria; School of Engineering, Lebanese American University, Byblos, Lebanon
Abstract
The nonlinear snap-through buckling of functionally graded (FG) carbon nanotube reinforced composite (CNTRC) curved tubes is analytically investigated in this research. It is assumed that the FG-CNTRC curved tube is supported on a threeparameter nonlinear elastic foundation and is subjected to the uniformly distributed pressure and thermal loads. Properties of the curved nanocomposite tube are distributed across the radius of the pipe and are given by means of a refined rule of mixtures approach. It is also assumed that all thermomechanical properties of the nanocomposite tube are temperature-dependent. The governing equations of the curved tube are obtained using a higher-order shear deformation theory, where the traction free boundary conditions are satisfied on the top and bottom surfaces of the tube. The von Kármán type of geometrical non-linearity
is included into the formulation to consider the large deflection in the curved tube. Equations of motion are solved using the twostep perturbation technique for nanocomposite curved tubes which are simply-supported and clamped. Closed-form expressions are provided to estimate the snap-buckling resistance of FG-CNTRC curved pipes rested on nonlinear elastic foundation in thermal environment. Numerical results are given to explore the effects of the distribution pattern and volume fraction of CNTs, thermal field, foundation stiffnesses, and geometrical parameters on the instability of the curved nanocomposite tube.
Address
Dan Chen, Jun Shao: Taizhou Vocational College of Science & Technology, Taizhou 318020, Zhejiang, China
Zhengrong Xu: Taizhou Jurong Plastics Co., LTD, Taizhou 318020, Zhejiang, China
Hadi Babaei: Department of Mechanical Engineering, South Tehran Branch, Islamic Azad University, Tehran, Iran
Abstract
Ratcheting is the cyclic buildup of inelastic strain on a structure resulting from a combination of primary and
secondary cyclic stress. It can lead to excessive plastic deformation, incremental collapse, or fatigue. Ratcheting has been numerically investigated on a cantilever beam, considering the current study's primary and secondary bending loads. In addition, the effect of input frequency on the onset of ratcheting has been investigated. The non-linear dynamic elastic-plastic approach has been utilized. Analogous to Yamashita's bending-bending ratchet diagram, a non-dimensional ratchet diagram with a frequency effect is proposed. The result presents that the secondary stress values fall sequentially with the increase of primary
stress values. Moreover, a displacement amplification factor graph is also established to explain the effect of frequency on ratchet occurrence conditions. In terms of frequency effect, it has been observed that the lower frequency (0.25 times the natural frequency) was more detrimental for ratchet occurrence conditions than the higher frequency (2 times the natural frequency) due to the effect of dynamic displacement. Finally, the effect of material modeling of ratcheting behavior on a beam is shown using different hardening coefficients of kinematic hardening material modeling.
Key Words
dynamic loading; finite element method; frequency; plastic deformation; ratcheting
Address
Sk. Tahmid Muhatashin Fuyad: Department of Mechanical Engineering, Khulna University of Engineering & Technology, Khulna, Bangladesh
Md Abdullah Al Bari: Department of Mechanical Engineering, Khulna University of Engineering & Technology, Khulna, Bangladesh; Department of Chemical and Petroleum Engineering, University of Calgary, Canada
Md. Makfidunnabi: Department of Mechanical Engineering, Khulna University of Engineering & Technology, Khulna, Bangladesh
H.M. Zulqar Nain: Department of Nuclear Engineering, University of Dhaka, Dhaka, Bangladesh
Mehmet Emin Özdemir: Department of Civil Engineering, Cankiri Karatekin University, 18100, Çankiri, Turkey
Murat Yaylaci: Department of Civil Engineering, Recep Tayyip Erdogan University, 53100, Rize, Turkey
Abstract
The present research delves into the analysis of nonlinear free and forced vibrations of porous functionally graded
(FG) shallow shells reinforced with oblique stiffeners, which are embedded in a nonlinear elastic foundation (NEF) subjected to external excitation. Two distinct types of PFG shallow shells, characterized by even and uneven porosity distribution along the thickness direction, are considered in the research. In order to model the stiffeners, Lekhnitskii's smeared stiffeners technique is implemented. With the stress function and first-order shear deformation theory (FSDT), the nonlinear model of the oblique stiffened shallow shells is established. The strain-displacement relationships for the system are derived via the FSDT and
utilization of the von-Kármán's geometric assumptions. To discretize the nonlinear governing equations, the Galerkin method is employed. The model such developed allows analysis of the effects of the stiffeners with various angles as desired, in addition to the quantitative investigation on the influence of the surrounding nonlinear elastic foundations. To numerically solve the problem of vibrations, the 4th-order P-T method is used, as this method, known for its enhanced accuracy and reliability, proves to be an effective choice. The validation of the present research findings includes a comprehensive comparison with outcomes
documented in existing literature. Additionally, a comparative analysis of the numerical results against those obtained using the 4th Runge-Kutta method is performed. The impact of stiffeners with varying angles and material parameters on the vibration characteristics of the present system is also explored. The researchers and engineers working in this field may use the results of this study as benchmarks in their design and research for the considered shell systems.
Key Words
FSDT; nonlinear elastic foundation; nonlinear free and forced vibrations; oblique stiffeners; porous FG
shallow shells; P-T method
Address
Kamran Foroutan and Liming Dai: Industrial Systems Engineering, University of Regina, Regina, SK, S4S 0A2, Canada
Abstract
In this study, a new sustainable material was proposed to prepare precast tunnel lining segments (TLS), which were produced using a fiber-reinforced slag-based geopolymer composite. Slag was used as the geopolymer binder. In addition, polypropylene and carbon fibers were added to reinforce TLSs. TLSs were examined in terms of flexural performance, loaddeflection response, ductility, toughness, crack characteristics, and tunnel boring machine (TBM) thrust force. Simultaneously, numerical simulation was performed using finite element analysis. The mechanical characteristics of the geopolymer composite with a fiber content of 1% were used. The results demonstrated that the flexural performance and load-deflection response of the precast TLSs were satisfactory. Furthermore, the numerical results were capable of predicting and realistically capturing the structural behavior of precast TLSs. Therefore, fiber-reinforced slag-based geopolymer composites can be applied as precast TLSs.
Key Words
GID software; finite element analysis; three-point flexural strength; toughness; tunnel lining
segment
Address
Arass Omer Mawlod: Civil Engineering Department, University of Raparin, Kurdistan Region, Iraq
Dillshad Khidhir Hamad Amen Bzeni: Civil Engineering Department, Salahadin University-Erbil, Kurdistan Region, Iraq
Abstract
Strengthening of hollow structural sections using through-bolts is a cost-effective and straightforward approach. It's a versatile method that can be applied during both design and service phases, serving as a non-disruptive and budget-friendly retrofitting solution. Existing research on axially loaded hollow sections T-joints has demonstrated that this technique can amplify the joint strength by 50%, where single bolt could enhance the strength of the joint by 35%. However, there's a gap in understanding their use for K-joints. As the behavior of K-joints is more complex, and they are widely existent in structures, this study aims to bridge that gap by conducting comprehensive parametric study using finite element analysis. Numerical investigation was conducted to evaluate the effect of through bolts on K-joints focusing on using single through bolt to achieve most of the strengthening effect. A full-scale parametric model was developed to investigate the effect of various geometric parameters of the joint. This study concluded the existence of optimal bolt location to achieve the highest strength gain for the joint. Moreover, a rigorous statistical analysis was conducted on the data to propose design equations to predict optimal bolt location and the corresponding strength gain implementing the verified by finite element models.
Key Words
finite element modeling; hollow sections; K-joints; strengthening; through bolt
Address
Amr Fayed, Ali Hammad and Amr Shaat: Department of Structural Engineering, Ain Shams University, Cairo, Egypt
Abstract
During strong seismic events, inelastic shear deformation occurs in beam-column joints. To capture inelastic shear deformation, an analytical model for beam-column joint in reinforced concrete (RC) frame structures has been proposed in this study. The proposed model has been developed using a rotational spring and rigid links. The stiffness properties of the rotational spring element have been assigned in terms of a moment rotation curve developed from the shear stress-strain backbone curve. The inelastic rotation behavior of joint has been categorized in three stages viz. cracking, yielding and ultimate. The joint shear stress and strain values at these stages have been estimated using analytical models and experimental database respectively. The stiffness properties of joint rotational spring have been modified by incorporating a geometry factor based on dimensions of adjoining beam and column members. The hysteretic response of the joint rotational spring has been defined by a pivot hysteresis model. The response of the proposed analytical model has been verified initially at the component level and later at the structural level with the two actually tested RC frame structures. The proposed joint model effectively emulates the inelastic behavior precisely with the experimental results at component as well as at structural levels.
Address
Kanak Parate: Department of Posts, Mumbai, India
Onkar Kumbhar: Walter P Moore, Pune, India
Ratnesh Kumar: Department of Applied Mechanics, Visvesvaraya National Institute of Technology, Nagpur, India
Abstract
Using negative Poisson's ratio materials, an innovative metallic-yielding damper is introduced for the first time in
this study. Through the use of ABAQUS commercial software, a nonlinear finite element analysis is conducted to determine the performance of the proposed system. Mild steel plates with elliptical holes are used for these types of dampers, which dissipate energy through an inelastic deformation of the constitutive material. To assess the capability of the proposed damper, nonlinear quasi-static finite element analyses have been conducted on the damper with a variety of geometric parameters. According to the results, the proposed system is ductile and has a high capacity to dissipate energy. The proposed auxetic damper has a specific energy absorption of 910.8 J/kg and a ductility of 33.6. Therefore, this damper can dissipate a large amount of earthquake input energy without buckling by increasing the buckling load of the brace with its ductile behavior. In addition, it was found that by incorporating auxetic dampers in the steel frame, the frame was made harder, stronger, and ductile and its energy absorption increased by 300%.
Key Words
ductility; energy dissipation; finite element modeling; yield damper
Address
Milad Masoodi, Ahmad Ganjali, Hamidreza Irani and Aboozar Mirzakhani: Department of Civil Engineering, Shahrood Branch, Islamic Azad University, Shahrood, Iran
