Abstract
The advantage of using yielding dampers with a multi-phase yielding mechanism (MPYM) is that the dampers yield
gradually, preventing the dampers from suddenly losing stiffness and strength. The study investigated the numerical and
analytical behavior of U-shaped dampers (UD) with an MPYM. Initially, the numerical model was calibrated using experimental
and analytical data. Then, extensive parametric analyses were conducted to investigate UD with an MPYM. The model's
variables encompassed the dimensions of the UD and their number in the model. The effects of these variables on elastic and
effective stiffness, energy dissipation, maximum strength, and equivalent viscous damping ratio (EVDR) were then calculated.
Analytical equations were proposed to estimate the force-displacement diagrams of the models. In addition, approximate
equations were presented to predict the effective stiffness, ultimate strength, and energy dissipation of the damper, making
calculations simpler. The UD was yielded in order from the highest elastic stiffness to the lowest in the model. Increasing the
ratio of elastic stiffness, yield strength, and the number of dampers in the model increased energy dissipation and EVDR.
Comparing the MPYM damper with traditional dampers reveals that the models do not exhibit a significant decrease in strength
and stiffness after the initial yield.
Key Words
energy dissipation; multi-phase yielding mechanism; numerical analysis; U-shaped yielding dampers
Address
Kambiz Cheraghi: Department of Civil Engineering, Faculty of Engineering, Razi University, Kermanshah, Iran.
Mehrzad TahamouliRoudsari:Department of Civil Engineering, Kermanshah Branch, Islamic Azad University, Kermanshah, Iran
Abstract
This study focuses on deriving an analytical approach to understand the free vibrational behavior of three
dimensional (3D) graphene foam-reinforced polymer matrix composites (GrF-PMC) cylindrical shells. The composite
incorporates porous graphene foams characterized by their 3D scaffold structures, aimed at enhancing the overall rigidity of the
material. Furthermore, the 3D graphene foams can be positioned either uniformly or variably across the shell's thickness. The
composite's effective Young's modulus, mass per unit volume, and Poisson's ratio are calculated using a mixture rule. Applying
first-order shear deformation shell theory, Donnell's assumptions, and Hamilton's principle, the governing equations are derived
and tackled through the state-space method. Numerical solutions are provided for various boundary constraints. The accuracy
and reliability of this approach are confirmed by benchmarking against existing literature. Additionally, the work explores how
the type of 3D-GrF framework, its weight proportion, foam coefficient, and geometric parameters such as thickness-to-radius
and length-to-radius ratios, along with boundary conditions, impact the natural frequencies of the cylindrical panel. The findings
reveal that both the configuration of the 3D-GrF network and its relative weight significantly affect the vibrational characteristics
of the GrF-PMC structures.
Key Words
curved panels; first order shear deformation shell theory; state space method; three-dimensional graphene
foams; vibration
Address
Ali Ahmadi:Civil and Environmental Engineering Program, Graduate School of Advanced Science and Engineering,
Hiroshima University, Hiroshima, Japan
Abstract
In this research, we tested 10 simply supported concrete-encased composite columns under monotonic eccentric
loads and investigated their shear behaviour. The specimens tested were two reinforced concrete specimens, three steel
reinforced concrete (SRC) specimens with an H-shaped steel section (also called a beam section), and five SRC specimens with
a cruciform-shaped steel section (also called a column section). The experimental variables included the transverse steel shape's
depth and the longitudinal steel flange's width. Experimental observations indicated the following. (1) The ultimate load
carrying capacity was controlled by web compression failure, defined as a situation where the concrete within the diagonal
strut's upper end was crushed. (2) The composite effect was strong before the crushing of the concrete outside the steel shape.
(3) We adjusted the softened strut-and-tie SRC (SST-SRC) model to yield more accurate strength predictions than those
obtained using the strength superposition method. (4) The MSST-SRC model can more reasonably predict shear strength at an
initial concrete softening load point. The rationality of the MSST-SRC model was inferred by experimentally observing shear
behaviour, including concrete crushing and the point of sharp variation in the shear strain.
Key Words
composite column; concrete-encased; shear strength; steel-reinforced concrete
Address
Keng-Ta Lin:Department of Civil and Environmental Engineering, National University of Kaohsiung, No.700,
Kaohsiung University Rd., 811, Kaohsiung, Taiwan, R.O.C.
Cheng-Cheng Chen:Department of Construction Engineering, National Taiwan University of Science and Technology,
No. 43, Sec. 4, Keelung Rd, 106, Taipei, Taiwan, R.O.C.
Abstract
An analytical investigation is proposed in this paper for cylindrical shell structures made of functionally graded
material(FGM) subjected to non-uniform external pressure for the first time. Elastic properties of shell material change
exponentially with respect to radial coordinate, and non-uniform lateral pressure is assumed to be arbitrary. The relation between
buckling pressure and non-uniform external pressure is directly established based on the perturbation method. Utilizing the
presented formula, uniform, axial linear, circumferentially varying and general non-uniform external pressure loads are analyzed
in detail. The obtained buckling pressure results are all new. The comparative studies indicate that buckling pressure for uniform
pressure coincides with those in literatures, and buckling pressure ratios of axial linear and circumferentially varying external
pressure for pure ceramic or metal material are in good agreement with those for isotropic shells. Furthermore, buckling pressure
for general non-uniform pressure is also validated by the Galerkin method. Numerical calculation and discussion on the effects
of shell dimensions, load parameters and material properties on buckling pressure are also conducted.
Key Words
analytical; buckling; cylindrical shells; FGM; non-uniform external pressure
Address
Licai Yang: National Key Laboratory of Nuclear Reactor Technology, Nuclear Power Institute of China, Chengdu, Sichuang, 610213, China
Abstract
The Steel Tube Reinforced Concrete (STRC) bridge pier is an advanced steel-concrete composite system, featured
by the integration of a centrally placed core steel tube into conventional reinforced concrete (RC) piers. This study
experimentally evaluates the fundamental seismic behavior of STRC piers through cyclic-loading test on six pier specimens,
comprising three STRC and three RC counterparts, designed with shear span ratios spanning 1.5 to 3.0. Damage progression and
failure modes were meticulously documented, followed by a systematic comparative analysis of key seismic performance
indicators between the two structural typologies. Experimental results reveal that STRC piers exhibit stable hysteretic responses
with gradual strength attenuation and stiffness degradation. While the embedded steel tube has negligible influence on initial
lateral stiffness, it significantly enhances lateral load capacity, deformability, energy dissipation, and self-centering capability
compare to RC piers. Crucially, the core steel tube suppresses brittle shear failure mechanisms in low shear span ratio specimen,
facilitating a transition to a relatively ductile failure mode. These findings validate that STRC piers integrate high load-carrying
capacity with controlled damage progression under severe seismic loading, providing a viable solution for enhancing the
resilience and post-earthquake serviceability of transportation infrastructure in seismically active regions.
Key Words
complex networks; mathematical simulation; mechanical behavior; nanotechnology
Address
Tian Tian:Hunan Provincial Communications Planning, Survey & Design Institute Co., Ltd., Changsha, P.R. China
Wen-wu Li:Hunan Provincial Communications Planning, Survey & Design Institute Co., Ltd., Changsha, P.R. China
Song Yan:Hunan Provincial Communications Planning, Survey & Design Institute Co., Ltd., Changsha, P.R. China
Wen-liang Qiu:School of Civil Engineering, Dalian University of Technology, Dalian, P.R. China
Abstract
Complex tubular structures are often exposed to aggressive environments that produce corrosion and, occasionally,
must be able to withstand extreme mechanical overloads. Thus, health monitoring, computational simulation tools, and repair
projects are critically required to assure the fulfillment of the expected service life. A very important retrofitting technique
consists of the use of carbon fiber-reinforced polymers. This paper proposes a new multi-scale formulation that describes the
coupling of corrosion/repair processes with plasticity and local buckling effects, specifically adapted for the analysis of complex
structures. A lumped damage model is proposed that includes corrosion laws in the constitutive equations. Coupling between
corrosion, repair, plasticity and local buckling is carried out by extended "interaction diagrams". Repair is characterized as a
"negative corrosion increment". The structural assessment is carried out by the introduction of a "damage driving rotation" that
determines the closeness of local buckling during cyclic loadings. Collapse risks are evaluated by using a local buckling state
variable. This new model is implemented as a finite element in which corrosion is a nodal degree of freedom. This
computational tool can be used for the design of deterministic or reliability-based management of inspection, maintenance, or
repair of offshore and other complex tubular structures.
Key Words
complex networks; mathematical simulation; mechanical behavior; nanotechnology
Address
Scarlet K. Montilla:School of Civil Engineering, Chongqing University, 400045, Chongqing, China
Yongtao Bai:School of Civil Engineering, Chongqing University, 400045, Chongqing, China
JiePeng Liu:School of Civil Engineering, Chongqing University, 400045, Chongqing, China
Ricardo Picon:Catholic University of Temuco. Department of Civil Engineering and Geology, Chile
Nestor Guerrero:Department of Civil Engineering, University of Ibague, Ibague, Colombia
Mohamed Elchalakani:School of Civil Engineering, Chongqing University, 400045, Chongqing, China
Julio Florez-Lopez:School of Civil Engineering, Chongqing University, 400045, Chongqing, China
