Abstract
Transient dynamic behavior of a sandwich beam under thermal and impulsive loads has been researched in the
context of higher-order beam theory. The impulse load of blast type has been enforced on the top exponent of the sandwich
beam while it is in a thermal environment. The core of the sandwich beam is cellular with auxetic rectangular pattern, whereas
the layers have been built with the incorporation of graphene oxide powder (GOP) and are micromechanically introduced
through Halpin-Tsai formulization. Governing equations for the sandwich beam have been solved through inverse Laplace
transform style for obtaining the dynamical deflections. The connection of beam deflections on temperature variability, GOP
quantity, pulse load situation and core relative density has been surveyed in detail.
Abstract
In order to study the shear mechanical behavior of prefabricated and assembled multi-key group stud connectors,
this paper conducted push-out tests on 10 prefabricated and assembled multi-key group stud connectors, distributed in 5 groups,
and detailed the failure modes of each specimen. Based on the finite element software, a total of 22 models of this type of stud
connector are established, and validated the finite element models using the push-out tests. Furthermore, the effects of stud
diameter, number of key groups, and spacing of key groups on the shear resistance of prefabricated and assembled multi-key
group stud connectors are analyzed. Combined with the test and finite element, the force analysis is carried out for the stud and
first-pouring and post-pouring concrete. The results show that the spacing and number of key groups have a significant impact
on the shear capacity and shear stiffness of the specimen. For a single stud, the shear force is transferred to the surrounding
concrete via the stud's root. When the stud is finally cut, the steel and the concrete plate are separated. Under vertical shear force,
the top row of studs experiences the highest shear, while the middle row has the least. Based on statistical regression, a formula
of assembled multi-key group stud connectors is proposed.
Key Words
complex networks; mathematical simulation; mechanical behavior; nanotechnology
Address
Liang Fan:1)School of Civil Engineering, Chongqing Jiaotong University, Chongqing 400074, China 2)State Key Laboratory of Mountain Bridge and Tunnel Engineering, Chongqing 400074, China
Wen Zeng, Wenhao Zhao and Mengting Wang:School of Civil Engineering, Chongqing Jiaotong University, Chongqing 400074, China
Abstract
The measurement of pile bearing capacity is crucial for the design of pile foundations, where in-situ tests could be
costly and time needed. The primary objective of this research was to investigate the potential use of fuzzy-based techniques to
anticipate the maximum weight that concrete driven piles might bear. Despite the existence ofseveral suggested designs, there is
a scarcity of specialized studies on the exploration of adaptive neuro-fuzzy inference systems (𝐴𝑁𝐹𝐼𝑆) for the estimation of pile
bearing capacity. This paper presents the introduction and validation of a novel technique that integrates the fire hawk optimizer
(𝐹𝐻𝑂) and equilibrium optimizer (𝐸𝑂) with the 𝐴𝑁𝐹𝐼𝑆, referred to as 𝐴𝑁𝐹𝐼𝑆𝐹𝐻𝑂 and 𝐴𝑁𝐹𝐼𝑆𝐸𝑂 , respectively. A
comprehensive compilation of 472 static load test results for driven piles was located within the database. The recommended
framework was built, validated, and tested using the training set (70%), validation set (15%), and testing set (15%) of the
dataset, accordingly. Moreover, the sensitivity analysis is performed in order to determine the impact of each input on the output.
The results show that 𝐴𝑁𝐹𝐼𝑆𝐹𝐻𝑂 and 𝐴𝑁𝐹𝐼𝑆𝐸𝑂 both have amazing potential for precisely calculating pile bearing capacity.
The 𝑅2 values obtained for 𝐴𝑁𝐹𝐼𝑆𝐹𝐻𝑂 were 0.9817, 0.9753, and 0.9823 for the training, validating, and testing phases. The
findings of the examination of uncertainty showed that the 𝐴𝑁𝐹𝐼𝑆𝐹𝐻𝑂 system had less uncertainty than the 𝐴𝑁𝐹𝐼𝑆𝐸𝑂 model.
The research found that the 𝐴𝑁𝐹𝐼𝑆𝐹𝐻𝑂 model provides a more satisfactory estimation of the bearing capacity of concrete driven
piles when considering various performance evaluations and comparing it with existing literature.
Abstract
In the current study, we aim to evaluate both microstructural characteristics and economic benefits of composite
structures from supply chain utilizing AI-based method. In this regard, the various aspects of microstructure of composite
materials along with the features of supply chain are discussed and quantified. In addition, the final economic aspects of the
composite materials and are also presented. Based on available data, a designed artificial neural network is utilized for prediction
of both microstructure and economical feature of the composite material. The results indicate that the supply chain could affect
the microstructure of final composite materials which in turn make changes in the mechanical properties and durability of
composite materials.
Abstract
Aluminum foams sandwich panel (AFSP) has been used in engineering field, where cyclic loading is used in most
of the applications. In this paper, the fatigue life of AFSP prepared by the bonding method was investigated through a three-point
bending test. The mathematical statistics method was used to analyze the influence of different plate thicknesses and core
densities on the bending fatigue life. The macroscopic fatigue failure modes and damage mechanisms were observed by
scanning electron microscopy (SEM). The results indicate that panel thickness and core layer density have a significant
influence on the bending fatigue life of AFSP and their dispersion. The damage mechanism of fatigue failure to cells in
aluminum foam is that the initial fatigue crack begins the cell wall, the thinnest position of the cell wall or the intersection of the
cell wall and the cell ridge, where stress concentrations are more likely to occur. The fatigue failure of aluminum foam core
usually starts from the semi-closed unit of the lower layer, and the fatigue crack propagates layer by layer along the direction of
the maximum shear stress. The results can provide a reference for the practical engineering design and application of AFSP.
Moulgada Abdelmadjid, Zagane Mohammed El Sallah, Murat Yaylaci, Ait Kaci Djafar, Benouis Ali,
Baltach Abdelghani, Seyyal Ozturk, Mehmet Emin Ozdemir and Ecren Uzun Yaylaci
Abstract
This study delves into the interaction dynamics between lateral notches and inclusions, providing valuable insights
for more effective engineering of structural components. By employing the finite element method, the research analyzes how
inclusions affect the dimensions and contours of the plastic zone under confined plasticity conditions. Several parameters were
investigated, including loading influence, the distance between the inclusion and notch tip, inclusion stiffness, and the
distribution of Von Mises stress, as well as normal stresses σxx and σyy, and Comparison between different stresses. Examining
stress distributions under varying loading conditions reveals a significant intensification, particularly near the crack tip.
Moreover, the presence of an inclusion near the notch base reduces both the size and shape of the plastic zone. The distribution
of the stresses for different loads knows an increase in intensity, especially near the crack head, which is the most requested by
the tensile forces on its upper part, which can cause either the crack's initiation or opening, inducing significant stresses.
Key Words
crack; inclusion; notch; plate; rigidity
Address
Moulgada Abdelmadjid: 1)Department of Mechanical Engineering, University of Ibn Khaldoun Tiaret, BP 78 14000, Tiaret, Algeria 2)LMPM Department of Mechanical Engineering, University of Djillali Liabes Sidi Bel Abbes, 22000, Algeria
Zagane Mohammed El Sallah: 1)Department of Mechanical Engineering, University of Ibn Khaldoun Tiaret, BP 78 14000, Tiaret, Algeria 2)LMPM Department of Mechanical Engineering, University of Djillali Liabes Sidi Bel Abbes, 22000, Algeria
Ait Kaci Djafar: LMPM Department of Mechanical Engineering, University of Djillali Liabes Sidi Bel Abbes, 22000, Algeria
Benouis Ali: 1)LMPM Department of Mechanical Engineering, University of Djillali Liabes Sidi Bel Abbes, 22000, Algeria 2)University of Moulay Taher, BP 138, City Ennasr Saida, 20000, Algeria
Baltach Abdelghani: Department of Mechanical Engineering, University of Ibn Khaldoun Tiaret, BP 78 14000, Tiaret, Algeria
Sevval Ozturk: Department of Civil Engineering, Recep Tayyip Erdogan University, 53100, Rize, Turkey
Mehmet Emin Ozdemir: Department of Civil Engineering, Cankiri Karatekin University, 18100, Çank
Abstract
This paper has focused on presenting vibration analysis of trapezoidal sandwich plates with a damaged core and FG wavy CNT-reinforced face sheets. A damage model is introduced to provide an analytical description of an irreversible rheological process that causes the decay of the mechanical properties, in terms of engineering constants. An isotropic damage is considered for the core of the sandwich structure. The classical theory concerning the mechanical efficiency of a matrix embedding finite length fibers has been modified by introducing the tube-to-tube random contact, which explicitly accounts for the progressive reduction of the tubes' effective aspect ratio as the filler content increases. The First-order shear deformation theory of plate is utilized to establish governing partial differential equations and boundary conditions for the trapezoidal plate. The governing equations together with related boundary conditions are discretized using a mapping-generalized differential quadrature (GDQ) method in spatial domain. Then natural frequencies of the trapezoidal sandwich plates are obtained using GDQ method. Validity of the current study is evaluated by comparing its numerical results with those available in the literature. After demonstrating the convergence and accuracy of the method, different parametric studies for laminated trapezoidal structure including carbon nanotubes waviness (0≤w≤1), CNT aspect ratio (0≤AR≤4000), face sheet to core thickness ratio (0.1 ≤ hf hc ≤ 0.5), trapezoidal side angles (30 0 ≤ α, β
≤ 90 0 ) and damaged parameter (0 ≤=≤ D 〈
1) are carried out. It is explicated that the damaged core and weight fraction, carbon nanotubes (CNTs) waviness and CNT aspect ratio can significantly affect the vibrational behavior of the sandwich structure. Results show that by increasing the values of waviness index (w), normalized natural frequency of the structure decreases, and the straight CNT (w=0) gives the highest frequency. For an overall comprehension on vibration of laminated trapezoidal plates, some selected vibration mode shapes were graphically represented in this study.
Address
Vanessa Valverde:Facultad de Mecanica, Escuela Superior Politecnica de Chimborazo (ESPOCH),
Panamericana Sur km 1 1/2, Riobamba, 060155, Ecuador
Patrik Viktor:Óbuda University, Keleti Karoly Faculty of Business and Management, Obuda University,
Tavaszmezou. 15-17, H-1084 Budapest, Hungary
Sherzod Abdullaey:1)Senior Researcher, Faculty of Chemical Engineering, New Uzbekistan University, Tashkent, Uzbekistan
2)Senior Researcher, Scientific and Innovation Department, Tashkent State Pedagogical University named after Nizami,
Tashkent, Uzbekistan
Nasrin Bohlooli:Nabi Data Science & Computational Intelligence Research Co., Tehran, Iran
Abstract
This paper presents an experimental and analytical study on a steel slit damper designed as an energy dissipative
device for earthquake protection of structures considering soil-structure interaction. The steel slit damper is made of a steel plate
with a number of slits cut out of it. The slit damper has an advantage as a seismic energy dissipation device in that the stiffness
and the yield force of the damper can be easily controlled by changing the number and size of the vertical strips. Cyclic loading
tests of the slit damper are carried out to verify its energy dissipation capability, and an analytical model is developed validated
based on the test results. The seismic performance of a case study building is then assessed using nonlinear dynamic analysis
with and without soil-structure interaction. The soil-structure system turns out to show larger seismic responses and thus seismic
retrofit is required to satisfy a predefined performance limit state. The developed slit dampers are employed as a seismic energy
dissipation device for retrofitting the case study structure taking into account the soil-structure interaction. The seismic
performance evaluation of the model structure shows that the device works stably and dissipates significant amount of seismic
energy during earthquake excitations, and is effective in lowering the seismic response of structures standing on soft soil.
