scholarly journals Temperature-Dependent Physical Characteristics and Varying Heat Effects on Nonlocal Rotating Nanobeams Due to Dynamic Load

2020 ◽  
Author(s):  
Ahmed E. Abouelregal ◽  
F. A. Mohammed ◽  
Mohamed V. Moustapha ◽  
Doaa Atta
Keyword(s):  
Thermal Conductivity ◽  
Current Model ◽  
Bending Moment ◽  
Thermodynamic Temperature ◽  
Dynamic Responses ◽  
Beam Model ◽  
Heat Effects ◽  
The Laplace Transform ◽  
Phase Lags ◽  
Generalized Heat Conduction

A theoretical nonlocal thermoelastic model for studying the effects of the thermal conductivity variability on a rotating nanobeam has been described in the present article. The theory of thermal stress is employed using the Euler–Bernoulli beam model and generalized heat conduction with phase lags. It is believed that the thermal conductivity of the current model varies linearly according to temperature. Due to variable harmonic heat, the considered nanobeam excited and was subjected to a time-varying exponential decay load. Using the Laplace transform process, the analytical solutions for displacement, deflection, thermodynamic temperature and bending moment of rotating nanobeams are provided in final forms and a numerical example has been taken to address the problem. A comparison of the stated results was displayed and additionally, the influences of non-local parameters and varying load were analyzed and examined. We also investigate how the linear changes in the temperature of physical properties can influence both the static and dynamic responses to the rotating nanobeam.

Influence of Initial Stress and Variable Thermal Conductivity on a Fiber-Reinforced Magneto-Thermoelastic Solid with Micro-Temperatures by Multi-Phase-Lags Model

2021 ◽  
pp. 2250007
Author(s):  
Amnah M. Alharbi ◽  
Samia M. Said ◽  
Elsayed M. Abd-Elaziz ◽  
Mohamed I. A. Othman
Keyword(s):  
Magnetic Field ◽  
Thermal Conductivity ◽  
Initial Stress ◽  
Thermodynamic Temperature ◽  
Variable Thermal Conductivity ◽  
Fiber Reinforced ◽  
Phase Lags ◽  
Multi Phase ◽  
The Impact ◽  
Physical Quantities

This paper presents the theory of multi-phase-lags thermoelasticity that was used to study the wave propagation on a fiber-reinforced thermoelastic medium with micro-temperatures. The medium was considered to be homogeneous, isotropic and thermal conductivity as a linear function of thermodynamic temperature. The Fourier transform and Laplace transform are employed to solve the governing equations and obtained the solution of the physical quantities. The graphical illustrations of the impact that initial stress, variable thermal conductivity, magnetic field, and the phase-lags have on the field functions are presented. The variable thermal conductivity, initial stress, and magnetic field have a good impact in all the physical quantities.

scholarly journals Thermoelastic Interactions in a Rotating Infinite Orthotropic Elastic Body with a Cylindrical Hole and Variable Thermal Conductivity

2017 ◽  
Vol 64 (4) ◽  
pp. 481-498 ◽  
Author(s):  
D. S. Mashat ◽  
A. M. Zenkour ◽  
A. E. Abouelregal
Keyword(s):  
Thermal Conductivity ◽  
Hoop Stress ◽  
Generalized Thermoelasticity ◽  
Variable Thermal Conductivity ◽  
Cylinder Surface ◽  
Laplace Transform Technique ◽  
Rotation Phase ◽  
The Laplace Transform ◽  
Phase Lags ◽  
Effects Of Rotation

Abstract In the present article, we introduced a new model of the equations of generalized thermoelasticity for unbounded orthotropic body containing a cylindrical cavity. We applied this model in the context of generalized thermoelasticity with phase-lags under the effect of rotation. In this case, the thermal conductivity of the material is considered to be variable. In addition, the cylinder surface is traction free and subjected to a uniform unit step temperature. Using the Laplace transform technique, the distributions of the temperature, displacement, radial stress and hoop stress are determined. A detailed analysis of the effects of rotation, phase-lags and the variability thermal conductivity parameters on the studied fields is discussed. Numerical results for the studied fields are illustrated graphically in the presence and absence of rotation.

Dynamic Rate Effects on Timoshenko Beam Response

1985 ◽  
Vol 52 (2) ◽  
pp. 439-445 ◽  
Author(s):  
T. J. Ross
Keyword(s):  
Timoshenko Beam ◽  
Bending Moment ◽  
Laplace Transform Method ◽  
Transform Method ◽  
Rate Effects ◽  
The Laplace Transform ◽  
Step Loading ◽  
Fixed End ◽  
Constitutive Formulation ◽  
Viscoelastic Timoshenko Beam

The problem of a viscoelastic Timoshenko beam subjected to a transversely applied step-loading is solved using the Laplace transform method. It is established that the support shear force is amplified more than the support bending moment for a fixed-end beam when strain rate influences are accounted for implicitly in the viscoelastic constitutive formulation.

Vibration and sound radiation analysis of the final drive assembly considering the gear-shaft coupling dynamics

2016 ◽  
Vol 230 (7-8) ◽  
pp. 1258-1275 ◽  
Author(s):  
Yawen Wang ◽  
Junyi Yang ◽  
Dong Guo ◽  
Teik C Lim
Keyword(s):  
Dynamic Models ◽  
Acoustic Analysis ◽  
Bending Moment ◽  
Moment Of Inertia ◽  
System Dynamic ◽  
Dynamic Responses ◽  
Propeller Shaft ◽  
Hypoid Gear ◽  
Gyroscopic Effect ◽  
Gear Mesh

A generalized dynamic model of driveline system is formulated that includes the coupling effect and gyroscopic moments of the propeller shaft and hypoid gear rotor assembly. Firstly, the dynamic models with only gear-shaft coupling, with only gyroscopic effect, and with both gear-shaft coupling and gyroscopic effect are analyzed and compared. The results show that the combined effects of the gear-shaft interaction and gyroscopic behavior have considerable influence on the system dynamic responses surrounding gear bending resonances, especially for the bearing responses. However, the gear out-of-phase torsional modes still dominate the gear mesh frequency response. Secondly, the influence of pinion bending moment of inertia, propeller shaft stiffness and bearing stiffness on the system dynamic responses are examined. The system responses are then applied to perform further vibration and acoustic analysis for an axle housing structure. Computational results reveal that NVH (noise, vibration, and harshness) refinement can be achieved by tuning the pinion bearing rotational stiffness and pinion bending moment of inertia for the example considered. This study provides an understanding of the interaction between hypoid gear pair and propeller shaft, and can be employed to enhance driveline system design.

scholarly journals Effect of Slam Force Duration on the Vibratory Response of a Lightweight High-Speed Wave-Piercing Catamaran

2015 ◽  
Vol 59 (02) ◽  
pp. 69-84
Author(s):  
Jason John McVicar ◽  
Jason Lavroff ◽  
Michael Richard Davis ◽  
Giles Thomas
Keyword(s):  
High Speed ◽  
Bending Strength ◽  
Experimental Studies ◽  
Bending Moment ◽  
Higher Order ◽  
Acute Angle ◽  
Beam Model ◽  
Higher Order Modes ◽  
Hull Structure ◽  
Vertical Bending Moment

When the surface of a ship meets the water surface at an acute angle with a high relative velocity, significant short-duration forces can act on the hull plating. Such an event is referred to as a slam. Slam loads imparted on ships are generally considered to be of an impulsive nature. As such, slam loads induce vibration in the global hull structure that has implications for both hull girder bending strength and fatigue life of a vessel. A modal method is often used for structural analysis whereby higher order modes are neglected to reduce computational effort. The effect of the slam load temporal distribution on the whipping response and vertical bending moment are investigated here by using a continuous beam model with application to a 112 m INCAT wave-piercing catamaran and correlation to full-scale and model-scale experimental data. Experimental studies have indicated that the vertical bending moment is dominated by the fundamental longitudinal bending mode of the structure. However, it is shown here that although the fundamental mode is dominant in the global structural response, the higher order modes play a significant role in the early stages of the response and may not be readily identifiable if measurements are not taken sufficiently close to the slam location. A relationship between the slam duration and the relative modal response magnitudes is found, which is useful in determining the appropriate truncation of a modal solution.

Thermo-viscoelastic fractional model of rotating nanobeams with variable thermal conductivity due to mechanical and thermal loads

2021 ◽  
pp. 2150297
Author(s):  
Ahmed E. Abouelregal ◽  
Hijaz Ahmad ◽  
Taher A. Nofal ◽  
Hanaa Abu-Zinadah
Keyword(s):  
Thermal Conductivity ◽  
Fractional Derivative ◽  
Integral Transformation ◽  
Nonlocal Parameter ◽  
Dynamic Strength ◽  
Thermodynamic Temperature ◽  
Phase Lag ◽  
Euler Beam ◽  
Two Phase ◽  
Conduction Model

This paper analyzes the thermoelastic dynamic behavior of simply supported viscoelastic nanobeams of fractional derivative type due to a dynamic strength load. The viscoelastic Kelvin–Voigt model with fractional derivative with Bernoulli–Euler beam theory is introduced. The generalized thermoelastic heat conduction model with a two-phase lag is also used. It is assumed that the beam is rotating at a uniform angular velocity and that the thermal conductivity varies linearly depending on the temperature. Due to a variable harmonic heat and retreating time-dependent load, the nanobeam is excited. The Laplace integral transformation technique is used as the solution method. The thermodynamic temperature, deflection function, bending moment, and displacement are numerically calculated. Results of fractional and integer viscoelastic material models are compared. In the studied system, the effect of the nonlocal parameter, viscosity and varying load on the solutions is shown, and the temperature-dependence of the thermal conductivity is analyzed.

scholarly journals Evaluation of Dynamic Soil-Pile-Structure Interactive Behavior in Dry Sand by 3D Numerical Simulation

2019 ◽  
Vol 9 (13) ◽  
pp. 2612 ◽  
Author(s):  
Sun Yong Kwon ◽  
Mintaek Yoo
Keyword(s):  
Numerical Model ◽  
Load Condition ◽  
Inertial Force ◽  
Bending Moment ◽  
Dynamic Responses ◽  
Finite Difference Approximation ◽  
Difference Approximation ◽  
Interactive Behavior ◽  
Dry Sand ◽  
Pile Length

A 3D numerical model based on finite-difference approximation was formulated to predict the dynamic soil-pile-structure interaction (SPSI) in dry sand. A non-linear elastic, Mohr–Coulomb plastic soil-constitutive model was adopted for the proposed methodology with a hysteretic damping model which can simulate nonlinear behavior of soil and an interface model which can predict separation and slippage between soil and pile according to the external load condition. Simplified continuum model was used to properly simulate the semi-infinite boundary and improve analysis efficiency. The proposed numerical model was validated by comparison with experimental results performed by Yoo (2013). Thereafter, a parametric study was also carried out to investigate the complex dynamic behavior of pile foundation under varying conditions. It was demonstrated that inertial force induced by superstructure is dominant for dynamic SPSI in dry sand whereas the kinematic force induced by soil deformation is relatively insignificant. Pile peak bending moment occurs at 30% of the pile length when pile length is no longer than 5 T and at about 30% of 5 T (1.6 T) when the pile length is longer than 5 T. The pile head fixity governed the peak bending moment profile of pile and affected the dynamic responses of the system in conjunction with other factors, such as pile rigidity.

scholarly journals Thrust and bending moment of rigid piles subjected to moving soil

2010 ◽  
Vol 47 (2) ◽  
pp. 180-196 ◽  
Author(s):  
Wei Dong Guo ◽  
H. Y. Qin
Keyword(s):  
Current Model ◽  
Bending Moment ◽  
Soil Movement ◽  
Model Pile ◽  
Experimental Apparatus ◽  
Lateral Soil Movement ◽  
Laterally Loaded ◽  
The Given ◽  
Maximum Thrust

An experimental apparatus was developed to investigate the behaviour of vertically loaded free-head piles in sand undergoing lateral soil movement (wf). A large number of tests have been conducted to date. Presented here are 14 typical model pile tests concerning two diameters, two vertical pile loading levels, and varying sliding depths with the movement wf driven by a triangular loading block. Results are provided for driving force as well as for induced shear force (T), bending moment (M), and deflection ( y) along the piles with wf / normalized sliding depth. The tests enable simple expressions to be proposed, drawn from the theory for a laterally loaded pile. The new expressions well capture the evolution of M, T, and y with soil movement observed in current model tests, and the three to five times difference in maximum bending moment (Mmax) from the two modes of loading. They further offer a good estimate of Mmax for eight in situ pile tests and one centrifuge test pile. The study quantifies the sliding resistance offered by a pile for the given wf profiles, pile location (relative to the boundary), and vertical load. It establishes the linear correlation between the maximum thrust (resistance T) and Mmax, regardless of the magnitudes of wf.

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