Journal of Structural Engineering & Applied Mechanics - Golden Light Publishing ® | Trabzon

Journal of Structural Engineering & Applied Mechanics

ARTICLES

Kasilingam Senthil Shailja Bawa C.P. Aswin

The numerical investigations has been carried out on simulating bond-slip behaviour between concrete and steel reinforcing bar using ABAQUS Explicit finite element code. The major contribution of this paper is to study the influence of varying concrete strength and diameter of reinforcing bar on bond slip behaviour. The inelastic behaviour of concrete and steel reinforcing bar were defined using concrete damaged plasticity model and Johnson-Cook model respectively which is available in ABAQUS/CAE. A spring-translator element available in ABAQUS, was used to simulate the bond slip phenomena in reinforced concrete during pull-out. The results thus predicted through simulations were compared with the experimental results available in literature. It was observed that the translator used in the present study simulates the bond behaviour efficiently. It was also observed that the predicted and measured deformed profile was found in good agreement. Further, the simulations were conducted on principal parameters to study the influence of concrete compressive strength and the bar diameter. In case of 40MPa concrete the bond stress improved by 60% when 16 mm diameter bars were replaced by 20 mm diameter bars. Increasing the bar diameter is an efficient method to improve the bond strength characteristics. However, the improvement in bond stress was found to be insignificant when concrete strength was increased from 60 MPa to 100 MPa.

https://doi.org/10.31462/jseam.2018.03105116


Onur Araz Volkan Kahya

Using different optimization techniques, the optimum characteristics of multiple tuned mass dampers (MTMD) for reducing the dynamic response of primary structure due to various excitations are studied by many researchers. In this paper, the five practical MTMD models are considered which consist of different combinations of the mass, damping, stiffness coefficient and damping ratio in the MTMD. The criteria selected for the optimality is the minimization of the maximum value of the displacement dynamic magnification factor (DMF) of the primary structure with the MTMD system under external harmonic excitation. The optimum parameters of the MTMD systems are investigated using Sequential Quadratic Programming (SQP). Results obtained illustrate that the optimum MTMD-1 and MTMD-4 have nearly the same control performance and provide higher effectiveness than all the other types of MTMDs of the same mass ratio in reducing the displacement response of primary structure. Finally, a robustness analysis of optimally designed MTMD systems to investigate their performance under errors in the tuned frequencies is also performed in detail.

https://doi.org/10.31462/jseam.2018.03117127


B.B. Аhmedov Ali M. Najafov A.I. Abdullayev

The petrol industry has very big impact on the modern world economy and politics. With any options and scenarios for the development of the economy in the coming years, natural resources, especially fossil oil products, will be the main factor of world economic growth. The sucker-rod pumps are one of the important aggregates for the mechanized oil recovery on land. However, the low efficiency, the big expenditure of the electric power, an incomplete construction of driving gear and reformative mechanisms, impossibility of use in existing aggregates of electric motors with a rotation high frequency lead to research of more perfect construction of a mechanical drive pumps. The present study describes a new design solution for a beamless sucker-rod pump for oil production, characterized by small dimensions and metal consumption, less energy consumption, better dynamic characteristics. The results of analytical kinematical studies and numerical calculations of the new beamless sucker-rod pump are presented.

https://doi.org/10.31462/jseam.2018.03128135


Gökhan Adıyaman Ahmet Birinci

In this paper, the receding contact problem of functionally graded (FG) layer resting on a Winkler foundation is considered. It is assumed that the shear modulus of the layer change functionally along the depth whereas Poisson ratio remains constant. Arbitrary concentrated loads by means of arbitrary rigid punches are applied to the top of the layer. The problem is considered as a plain strain problem. A general formulation is obtained using elasticity theory and Fourier integral transform. Obtained formulation is valid for both symmetric and asymmetric systems. A parametric study is carried out to investigate the effect of material properties and loading on contact distances and contact pressures. It is found that, increasing rigidity of the bottom of the FG layer compared to the top of the FG layer, the contact distances between the circular punch and FG layer contact surface decreases whereas maximum contact pressure increases. In addition, placement of the rigid punches has an effect on the contact distances and contact pressures.

https://doi.org/10.31462/jseam.2018.03136146


Muhammet Karaton Halmat Ahmet

In this study, the nonlinear static Pushover analyses of a reinforced concrete portal frame are obtained by using Fiber element method based on displacement. For calculating of cyclic behavior of concrete, the Mander-Priestley-Park model is used. Cyclic behavior of the reinforcement is obtained by using Mengotto-Pinto steel model. Different longitudinal reinforcement ratios are selected for investigating effect on the nonlinear behavior of a portal frame under horizontal forces. Concrete mean strength is 20 MPa and confinement factor is 1.2. The yield strength of reinforcement model is 420 MPa. Obtained results are evaluated with regard to the top displacement-base shear force and top rotation-base moment. The lateral load capacities and the overturning moment capacities obtained from 2nd, 3rd, 4th and 5th cases were calculated more between 81-200% and 101-286% than 1st case, respectively. As a results, it is determined that the lateral load capacity and the overturning moment capacity increase depending on increasing of longitudinal reinforcement ratio in columns.

https://doi.org/10.31462/jseam.2018.03147154