Abstract
Effects of MHD slip flow of second grade fluid with heat transfer are studied in the presence of heat source along permeable stretching surface. The governing boundary layer equations are complex and partial in nature. Using Lie group theory the suitable similarity transformation is derived. The system of PDEs is transformed to system of ODEs by applying these similarity transformations. The combined effect of Hartman number and porosity on velocity profile and the influence of slip parameter on fluid velocity is observed. It is found that enhancing the second grade parameter, boundary layer thickens and ultimately speedup the fluid. Also, the effect of suction/injection parameter on velocity profile is checked. An excellent agreement is noticed that assures the correctness of results. Effects of various physical parameters on the velocity and temperature profile are elaborated with graphs.
Key Words
boundary value problem; exact solution; permeable surface; MHD flow; second grade fluid
Address
(1) Waheed Iqbal:
Department of Mathematics, Govt. College University Faisalabad, 38000, Faisalabad, Pakistan;
(2) Mudassar Jalil:
Department of Mathematics, COMSATS Institute of Information Technology, Park Road, Chak Shahzad, 44000 Islamabad, Pakistan;
(3) Mohamed A. Khadimallah:
Department of Civil Engineering, College of Engineering in Al-Kharj, Prince Sattam Bin Abdulaziz University, Al-Kharj, 11942, Saudi Arabia;
(4) Hamdi Ayed:
Department of Civil Engineering, College of Engineering, King Khalid University, Abha - 61421, Saudi Arabia;
(5) Ikram Ahmad, Javeria Umbreen, Bazal Fatima:
Department of Chemistry, University of Sahiwal, Sahiwal, 57000, Pakistan;
(6) Rana Muhammad Akram Muntazir:
Department of Mathematics, Lahore Leads University, 54792, Lahore, Pakistan;
(7) Abir Mouldi:
Department of Industrial Engineering, College of Engineering, King Khalid University, Abha - 61421, Saudi Arabia;
(8) Muzamal Hussain, Ghulam Murtaza:
Department of Mathematics, University of Sahiwal, Sahiwal, 57000, Pakistan;
(9) Essam Mohammed Banoqitah:
Nuclear Engineering Department, Faculty of Engineering, King Abdulaziz University, Jeddah P.O. Box 80204, Jeddah 21589, Saudi Arabia;
(10) Muhammad Taj:
Department of Mathematics, University of Azad Jammu and Kashmir, Muzaffarabad, 1300, Azad Kashmir, Pakistan;
(11) Zafer Iqbal:
Department of Mathematics, University of Sargodha, Sargodha, Punjab, Pakistan;
(12) Zafer Iqbal:
Department of Mathematics, University of Mianwali, Punjab, Pakistan.
Abstract
Cantilever structures demonstrate diverse nonlocal effects, resulting in either stiffness hardening or dynamic softening behaviors, as various studies have indicated. This research delves into the free and forced vibration analysis of rotaing nanoscale cylindrical beams and tubes under external dynamic stress, aiming to thoroughly explore the nonlocal impact from both angles. Utilizing Euler-Bernoulli and Reddy beam theories, in conjunction with higher-order tube theory and amilton's principle, nonlocal governing equations are derived with precise boundary conditions for both local and nonlocal behaviors. The study specifically examines two-dimensional functionally graded materials (2D-FGM), characterized by axially functionally graded (AFG) and radial porosity distributions. The resulting partial differential equations are solved using the generalized differential quadrature element method (GDQEM) and Newmark-beta procedures to acquire time-dependent results. This investigation underscores the significant influence of boundary conditions when nonlocal forces act on cantilever structures.
Key Words
beam theory; bending vibration; forced vibration; rotating; stability analysis; time dependent analysis; tube theory
Address
(1) Luxin He:
Beijing No. 5 Construction Engineering Group Co., Ltd.Beijing,100028, China;
(2) Mostafa Habibi:
Department of Biomaterials, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences, Chennai 600 077, India;
(3) Mostafa Habibi, Majid Khorami:
UTE University, Faculty of Architecture and Urbanism, Architecture Department, Calle Rumipamba S/N and Bourgeois, Quito, Ecuador;
(4) Mostafa Habibi:
Department of Mechanical Engineering, Faculty of Engineering, Haliç University, 34060, Istanbul, Turkey;
(5) Mostafa Habibi:
Institute of Research and Development, Duy Tan University, Da Nang 550000, Viet Nam.
Abstract
Concrete, consisting mainly of cement, water and aggregates; is the most used construction material all over the world. Cement manufacturing industry is one of the carbon dioxide producing sources that contributes to global warming. Therefore, in the last few years, there is a growing interest in using waste materials and by-products as cement replacement materials. Using these kinds of materials as a part of cement replacement reduces the air pollution, cost and also enhances some properties of concretes. In the present work, marble dust (MD) was examined as a partial cement replacement material with seven proportions as 0%, 10%, 20%, 30%, 40%, 50%, 60% and glass powder (GP) was used as an additive, 8% by cement weight, in a 0.55 water-binder ratio concrete. In order to evaluate their effects; workability, strength (compressive, flexural and split tensile), alkalinity, sulphate resistance and ultrasonic pulse velocity tests were performed. Experimental results indicated that with MD replacement and GP addition; there is a loss in the workability but improvement in mechanical properties. With 10% replacement of MD compressive, flexural and tensile strengths increased by 10.7%, 6.2% and 5.3% respectively. Moreover, up to 30% replacement of MD reasonable strength values were obtained.
Abstract
As a supplemental energy dissipation device, friction dampers are widely employed to augment the behaviour of buildings under seismic forces. In the current work, a methodology for the design of the friction damping system of RC frame buildings is offered using performance-based plastic design (PBPD) method. Here 2% of maximum interstorey drift ratio for life safety (LS) level is taken into account as a target drift to estimate the design base shear. In this approach, the distribution of friction damper is determined based on the hysteretic energy demand of that storey. Two frames, five storey three bay (5S3B) and eight storey three bay (8S3B) RC frame building with and without friction damping systems are also taken up for the investigation. The suggested design approach is validated by the nonlinear time history analysis (NLTHA) procedure. Inter story drift ratio (ISDR) and storey displacement, which are the more closely related to structural damage during seismic excitation are evaluated. The results show that the friction damping system on a retrofitted RC frame building performs effectively under seismic excitations and that storey displacement and ISDR are within the limit at moderate and high seismic intensities.
Key Words
friction damper; nonlinear time history; performance based plastic design; reinforced concrete; retrofitting
Address
Department of Civil Engineering, National Institute of Technical Teachers' Training & Research, Kolkata, Kolkata-700106, West Bengal, India.
Abstract
The behavior of confined steel fiber-reinforced concrete (including confinement models) with compressive strengths ranging from normal to high strength is still rarely studied. This paper presents the results of an investigation of fifteen confined concrete cylinders containing steel fiber. The design parameters evaluated in the experiment included concrete compressive strength (covers normal to high strength), volume fraction of steel fiber and hoop spacing. The main objective of this study was to evaluate the behavior of confined steel fiber concrete by reviewing several design parameters, such as concrete strength (normal to high strength). It is then developed to be an analytical stress-strain expression for confined steel fiber concrete. The experimental program was carried out by making cylindrical specimens with a diameter of 100 mm and a height of 200 mm. The cylindrical test object is compressed in a monotonic uniaxial loading. Experimental results have shown steel fiber in concrete has an important role in increasing the compressive strength and strain of cylindrical concrete without steel fiber. In addition, the value of strength enhancement of confined concrete (K) along with increasing fiber fraction volume; which applies to normal to high-strength concrete. The value of K also increases if the compressive strength of the concrete tends to decrease and the spacing of the hoops is closer. The comparison of stress-strain behavior between the confined steel fiber concrete proposed by other researchers and the experimental results in general significantly different in post-peak response. The statistical analysis indicates that the value of Coefficient of Variation for the confinement model by Campione is the closest compared to other existing confinement models in predicting the values of K and Toughness Index. Furthermore, the analytic stress-strain expression of confined steel fiber concrete was developed by adopting and modifying several equations from the present models. The proposed analytical expression is then verified with the experimental results. The results of the verification show that the stress-strain behavior of confined steel fiber concrete is relatively close.
Address
(1) Purwanto:
Universitas Semarang, Department of Civil Engineering, Semarang, Indonesia;
(2) Antonius, Lisa Fitriyana:
Universitas Islam Sultan Agung, Department of Civil Engineering, Semarang, Indonesia.
