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CONTENTS
Volume 60, Number 2, October25 2016
 

Abstract
The present article is aimed at an investigation of stresses produced in a microstretch elastic halfspace due to a moving load. The expressions of normal stress, shear stress and tangential couple stress produced in this case have been obtained in closed form. To find the displacement fields the perturbation method is applied. Significant effect of moving load on variation of stresses developed at different depths below the surface due to the depth of substrate and frictional coefficient of the rough surface of the medium has been observed. The effects of different shapes of irregularity and depth of irregularity on normal, shear and tangential couple stresses have been discussed. Some particular cases have also been deduced from the present investigation. Finally, the analytical developments have been illustrated numerically for aluminiumepoxy- like material substrate under the action of moving load.

Key Words
moving load; microstretch; frictional coefficient; irregularity; stresses

Address
Tanupreet Kaur and Satish Kumar Sharma: School of Mathematics, Thapar University, Patiala-147004, Punjab, India
Abhishek Kumar Singh and Mriganka Shekhar Chaki: Department of Applied Mathematics, Indian School of Mines, Dhanbad-826004, Jharkhand, India

Abstract
In this study, wave force tests were carried out for the four types of offshore support structures with scale factor 1:25 and wave forces to the support structure shapes were investigated. As the results of this study, it was found that, as the wave period increased at the normal wave condition, wave force decreased for the most cases. Extreme wave force was affected by the impact wave force. Impact wave force of this study significantly effect on Monopile and slightly on GBS and Hybrid type. Accordingly, Hybrid type indicated even lower wave force at the extreme and irregular wave conditions than the Monopile although Hybrid type indicated higher wave force at the normal wave condition of the regular wave because of the larger wave area of wave body. In respects of the structural design, since critical loading is extreme wave force, it should be contributed to improve structural safety of offshore support structure. However, since the impact wave force has nonlinearity and complication dependent on the support structure shape, wave height, wave period, and etc., more research is needed to access the impact wave force for other support structure shapes and wave conditions.

Key Words
offshore; support structure; shape; wave force test; impact wave force; extreme wave

Address
Youn-Ju Jeong, Min-Su Park and Young-Jun You: Structural Engineering Research Institute, Korea Institute of Civil Engineering and Building Technology, 283 Goyangdae-ro, ilsanseo-gu, Goyang, Gyeonggi 10223, Republic of Korea

Abstract
Static loading and fluid impact tests on plates containing mesh reinforcement and polypropylene fibers in ratios of 0 to 3% by volume were performed. The objective was to observe the effect of fluid mass on the total impulse that caused the impact event and the influence of fiber amount on the impact resistance, and to estimate the velocity of fluid that causes scabbing, perforation or total disintegration. The study is the first to express the fluid impact resistance of polypropylene fiber reinforced concrete plates.

Key Words
fluid impact; polypropylene fibers; projectile; plate; static loading

Address
Hasan Korucu: Turkish Armed Forces Headquarters, Department of Engineering, 06100 Bakanliklar, Ankara, Turkey: Purdue University, Lyles School of Civil Engineering, West Lafayette, IN 47907, United States

Abstract
Fluid impact tests on plates containing mesh reinforcement and polypropylene fibers were modeled and simulated using explicit finite element analysis software, LS-DYNA. The scabbing dimensions obtained by the experiments and the simulations were compared and crack formations were matched. The objective was to test the accuracy and fidelity of the model and to confirm that damage caused by fluid impact on the plates can be estimated with a reasonable accuracy over a wide range of impact velocity.

Key Words
fluid impact; polypropylene fibers; projectile; LS-DYNA; smoothed particle hydrodynamics

Address
Hasan Korucu: Turkish Armed Forces Headquarters, Department of Engineering, 06100 Bakanliklar, Ankara, Turkey: Purdue University, Lyles School of Civil Engineering, West Lafayette, IN 47907, United States

Abstract
There are constraints on truck weight, axle configurations and size imposed by departments of transportation around the globe due to structural capacity limitations of highway pavements and bridges. In spite of that, freight movers demand some vehicles that surpass the maximum size and legal weight limits to use the transportation network. Oversized trucks serve the purpose of spreading the load on the bridge; thus, reducing the load effect on the superstructure. For such vehicles, often a quick structural analysis of the existing bridges along the traveled route is needed to ensure that the structural capacity is not exceeded. For a wide vehicle having wheel gage larger than the standard 1830 mm, the girder distribution factors in the design specifications cannot be directly used to estimate the live load in the supporting girders. In this study, a simple approach that is based on finite element analysis is developed by modifying the AASHTO LRFD\'s girder distribution factors for slab-on-steel-girder bridges to overcome this problem. The proposed factors allow for determining the oversized vehicle bending moment and shear force effect in the individual girders as a function of the gage width characteristics. Findings of the study showed that the relationship between the girder distribution factor and gage width is more nonlinear in shear than in flexure. The proposed factors yield reasonable results compared with the finite element analysis with adequate level of conservatism.

Key Words
bridges; girder distribution factor; finite element; oversized vehicle; permit truck; super load

Address
Sami W. Tabsh: Department of Civil Engineering, American University of Sharjah, P.O. Box 26666, Sharjah, UAE
Muna M. Mitchell: Walter P Moore, 221 West Sixth Street, Suite 800, Austin, TX 78701, USA

Abstract
In common structural systems, there are some limitations to provide adequate lateral stiffness, high ductility, and architectural openings simultaneously. Consequently, the concept of T-Resisting Frame (TRF) has been introduced to improve the performance of structures. In this study, Configuration of TRF is a Vertical I-shaped Plate Girder (V.P.G) which is placed in the middle of the span and connected to side columns by two Horizontal Plate Girders (H.P.Gs) at each story level. System performance is improved by utilizing rigid connections in link beams (H.P.Gs). Plastic deformation leads to tension field action in H.P.Gs and causes energy dissipation in TRF; therefore, V.P.G. High plastic deformation in web of TRF\'s members affects the ductility of system. Moreover, in order to prevent shear buckling in web of TRF\'s members and improve overall performance of the system, appropriate criteria for placement of web stiffeners are presented in this study. In addition, an experimental study is conducted by applying cyclic loading and using finite element models. As a result, hysteresis curves indicate adequate lateral stiffness, stable hysteretic behavior, and high ductility factor of 6.73.

Key Words
T-Resisting Frame; experimental study; finite element; link beams; shear yielding; ductility factor

Address
Payam Ashtari: Department of Civil Engineering, University of Zanjan, Zanjan, 45371-38791, Iran
Helia Barzegar Sedigh: Department of Civil Engineering, Imam Khomeini International University, Qazvin, 34149-16818, Iran
Farzaneh Hamedi: Department of Civil Engineering, Imam Khomeini International University, Qazvin, 34149-16818, Iran

Abstract
In this article, based on the higher-order shear deformation plate theory, buckling analysis of a rectangular plate made of functionally graded piezoelectric materials and its effective parameters are investigated. Assuming the transverse distribution of electric potential to be a combination of a parabolic and a linear function of thickness coordinate, the equilibrium equations for the buckling analysis of an FGP rectangular plate are established. In addition to the Maxwell equation, all boundary conditions including the conditions on the top and bottom surfaces of the plate for closed and open circuited are satisfied. Considering double sine solution (Navier solution) for displacement field and electric potential, an analytical solution is obtained for full simply supported boundary conditions. The accurate buckling load of FGP plate is presented for both open and closed circuit conditions. It is found that the critical buckling load for open circuit is more than that of closed circuit in all loading conditions. Furthermore, it is observed that the influence of dielectric constants on the critical buckling load is more than those of others.

Key Words
buckling; functionally graded piezoelectric; rectangular plate; dielectric constants; piezoelectric constants; analytical solution

Address
M.A. Ghasemabadian and M. Kadkhodayan: Department of Mechanical Engineering, Ferdowsi University of Mashhad, Mashhad, Iran

Abstract
In a concrete member under pure tension, the stress in concrete is uniformly distributed over the whole concrete section. It is supposed that a local bond failure occurs at each crack, and there is a relative slip between steel and surrounding concrete. The compatibility of deformation between the concrete and reinforcement is thus not maintained. The bond transfer length is a length of reinforcement adjacent to the crack where the compatibility of strain between the steel and concrete is not maintained because of partially bond breakdown and slip. It is an empirical measure of the bond characteristics of the reinforcement, incorporating bar diameter and surface characteristics such as texture. Based on results from a series of previously conducted long-term tests on eight restrained reinforced concrete slab specimens and material properties including creep and shrinkage of two concrete batches, the ratio of final bond transfer length after all shrinkage cracking, to THE initial bond transfer length is presented.

Key Words
bond transfer length; creep; shrinkage; pure tension; one way slab

Address
Behnam Vakhshouri: Centre for Built Infrastructure Research (CBIR), Faculty of Engineering and Information Technology (FEIT), University of Technology Sydney (UTS), Sydney, Australia

Abstract
In this article, a four-variable refined plate theory is presented for buckling analysis of functionally graded plates subjected to uniform, linear and non-linear temperature rises across the thickness direction. The theory accounts for parabolic distribution of the transverse shear strains, and satisfies the zero traction boundary conditions on the surfaces of the plate without using shear correction factor. Young\'s modulus and Poisson ratio of the FGM plates are assumed to remain constant throughout the entire plate. However, the coefficient of thermal expansion of the FGM plate varies according to a power law form through the thickness coordinate. Equilibrium and stability equations are derived based on the present theory. The influences of many plate parameters on buckling temperature difference such ratio of thermal expansion, aspect ratio, side-to-thickness ratio and gradient index will be investigated.

Key Words
thermal properties; buckling; refined plate theory; functionally graded material; thermal expansion ratio; analytical modeling

Address
Abdelmoumen Anis Bousahla: Centre Universitaire de Relizane, Algerie; Laboratoire de Modelisation et Simulation Multi-echelle, Université de Sidi Bel Abbes, Algeria
Samir Benyoucef: Material and Hydrology Laboratory, Faculty of Technology, Civil Engineering Department, University of Sidi Bel Abbes, Algeria
Abdelouahed Tounsi: Laboratoire de Modelisation et Simulation Multi-echelle, Universite de Sidi Bel Abbés, Algeria; Material and Hydrology Laboratory, Faculty of Technology, Civil Engineering Department, University of Sidi Bel Abbes, Algeria
S.R. Mahmoud: Department of Mathematics, Faculty of Science, King Abdulaziz University, Saudi Arabia; Mathematics Department, Faculty of Science, University of Sohag, Egypt

Abstract
Even though extensive researches have been performed for steam explosion due to their complex mechanisms and inherent uncertainties, establishment of severe accident management guidelines and strategies is one of state-of-the arts in nuclear industry. The goal of this research is primarily to examine effects of vessel failure modes and locations on nuclear facilities under typical steam explosion conditions. Both discrete and integrated models were employed from the viewpoint of structural integrity assessment of steel components and evaluation of the cracking and crushing in reinforced concrete structures. Thereafter, comparison of systematic analysis results was performed; despite the vessel failure modes were dominant, resulting maximum stresses at the all steel components were sufficiently lower than the corresponding yield strengths. Two failure criteria for the reinforced concrete structures such as the limiting failure ratio of concrete and the limiting strains for rebar and liner plate were satisfied under steam explosion conditions. Moreover, stresses of steel components and reinforced concrete structures were reduced with maximum difference of 12% when the integrated model was adopted comparing to those of discrete models.

Key Words
containment wall penetration; finite element analysis; main piping; reactor cavity; steam explosion

Address
Seung Hyun Kim and Yoon-Suk Chang: Department of Nuclear Engineering, Kyung Hee University, 1732 Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do, 17104, Republic of Korea
Yong-Jin Cho: Korea Institute of Nuclear Safety, 62 Gwahak-ro, Yuseong-gu, Daejeon-si, 34142, Republic of Korea

Abstract
Exact solutions for stresses, strains, displacements, and the stress concentration factors of a rectangular plate perforated by an arbitrarily located circular hole subjected to in-plane pure shear loading are investigated by two-dimensional theory of elasticity using the Airy stress function. The hoop stresses, strains, and displacements occurring at the edge of the circular hole are computed and plotted. Comparisons are made for the hoop stresses and the stress concentration factors from the present study and those from a rectangular plate with a circular hole under uni-axial and bi-axial uniform tensions and in-plane pure bending moments on two opposite edges.

Key Words
perforated plate; stress concentration factor; non-central hole; in-plane pure shear; hoop stress; airy stress function; exact solution

Address
Yeong-Bin Yang: Department of Civil Engineering, National Taiwan University, Taipei 10617, Taiwan; School of Civil Engineering, Chongqing University, Chongqing 400045, China
Jae-Hoon Kang: Department of Architectural Engineering, Chung-Ang University, Seoul 156-756, Republic Korea


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