Abstract
The present research is focused on the study of plane harmonic waves in a two-dimensional orthotropic magneto-thermoelastic media with fractional order theory of generalized thermoelasticity in the light of twotemperature and rotation due to time harmonic sources. Here, we studied three types of waves namely quasilongitudinal (QL), quasi-transverse (QTS) and quasi thermal (QT) waves. The variations in the wave properties such as phase velocity, attenuation coefficient and specific loss have been noticed with respect to frequency for the reflected waves. Further the value of amplitude ratios, energy ratios and penetration depth are computed numerically with respect to angle of incidence. The numerical simulated results are presented graphically to show the effect of fractional parameter based on its conductivity (0 Key Words
amplitude ratios; attenuation coefficient; energy ratios; fractional order; frequency; harmonic plane waves; orthotropic medium; penetration depth; phase velocity; rotation; specific loss; three-phase lags
Address
Himanshi and Parveen Lata: Department of Mathematics, Punjabi University, Patiala, Punjab, India
Abstract
A theoretical method is developed to analyze the free vibration of an elastic annular plate in contact with an ideal liquid. The displacement potential functions of the contained liquid are expressed as a combination of the Bessel functions that satisfy the Laplace equation and the liquid boundary conditions. The compatibility condition along the interface between the annular plate and the contained liquid is taken into account to consider the fluidstructure coupling. The dynamic displacement of the wet annular plate is assumed to be a combination of dry eigenfunctions, allowing for prediction of the natural frequencies using the Rayleigh-Ritz method. The study investigates the effect of radial liquid boundary conditions on the natural frequencies of the wet annular plate, considering four types of liquid bounding: outer container bounded, outer and inner bounded, inner bounded, and radially unbounded. The proposed theoretical method is validated by comparing the predicted wet natural frequencies with those obtained from finite element analysis, showing excellent accuracy. The results indicate that the radial liquid bounding effect on the natural frequencies is negligible for the axisymmetric vibrational mode, but relatively significant for the mode with one nodal diameter (n = 1) and no nodal circle (m' = 0). Furthermore, the study reveals that the wet natural frequencies are the largest for the plate with an inner bounded cylinder among the radial liquid boundary cases, regardless of the vibration mode.
Address
Kyeong-Hoon Jeong: SMART System Development Division, Korea Atomic Energy Research Institute, 111 Daedeok-daero 989 Beon-gil, Yuseong, Daejeon, 34057, Republic of Korea
Abstract
In this study, a simple method for the determination of the shear correction factor for composites beam with a rectangular cross section is presented. The plane stress elasticity assumption is used after simplifications of the expression of the stress distribution in the beam. The different fiber orientation angle and volume fraction are considered in this work. The studied structure is subjected to various loading type (thermal and hygrothermal). The
numerical results obtained show that there is a dependence of the shear coefficient on the orientation of the fibers.
The evolution of the shear correction factors depends not only on the orientation of the fibers and also on the volume
fraction and the environment. the advantage of this developed formula of the shear correction factor is to obtain more precise results and to consider several parameters influencing this factor which are neglected if the latter is constant.
Key Words
beams; correction factors; fiber orientation; hygrothermal environment; shear; stress distribution
Address
Soumia Benguediab: Department of Civil Engineering and Hydraulic, University of Saida, Algeria; Material and Hydrology Laboratory, Faculty of Technology, Civil Engineering Department, University of Sidi Bel Abbes, Algeria
Fatima Zohra Kettaf: Department of Mechanical Engineering, University of Sciences and Technology Mohamed Boudiaf Oran,
Algeria
Mohammed Sehoul: Institute of Sciences and Technology, University Center Nour Bachir of El Bayadh, Algeria; Laboratory of Materials and Reactive Systems, Department of Mechanical Engineering, University Djillali Liabes of Sidi Bel Abbes, Algeria
Fouad Bourada: Material and Hydrology Laboratory, Faculty of Technology, Civil Engineering Department, University of Sidi Bel Abbes, Algeria; Science and Technology Department, Faculty of Science and Technology, Tissemsilt University, Algeria
Abdelouahed Tounsi: Material and Hydrology Laboratory, Faculty of Technology, Civil Engineering Department,
University of Sidi Bel Abbes, Algeria; YFL (Yonsei Frontier Lab), Yonsei University, Seoul, Korea; Department of Civil and Environmental Engineering, King Fahd University of Petroleum & Minerals, 31261 Dhahran, Eastern Province, Saudi Arabia
Mohamed Benguediab: Laboratory of Materials and Reactive Systems, Department of Mechanical Engineering, University Djillali Liabes of Sidi Bel Abbes, Algeria
Abstract
The determination of the blast protection level and the corresponding minimum load-bearing capacity for a laminated glass (LG) window is of crucial importance for safety and security design purposes. In this paper, the focus is given to the window response under near-field blast loading, i.e., where relatively small explosives would be activated close to the target, representative of attack scenarios using small commercial drones. In general, the assessment of the load-bearing capacity of a window is based on complex and expensive experiments, which can be conducted for a small number of configurations. On the other hand, nowadays, validated numerical simulations tools based on the Finite Element Method (FEM) are available to partially substitute the physical tests for the assessment of the performance of various LG systems, especially for the far-field blast loading. However, very little literature is available on the LG window performance under near-field blast loads, which differs from far-field situations in two points: i) the duration of the load is very short, since the blast wavelength tends to increase with the distance and ii) the load distribution is not uniform over the window surface, as opposed to the almost plane wave configuration for far-field configurations. Therefore, the current study focuses on the performance assessment and structural behaviour of LG windows under near-field blasts. Typical behavioural trends are investigated, by taking into account possible relevant damage mechanisms in the LG window components, while size effects for target LG windows are also addressed under a multitude of blast loading configurations.
Key Words
blast; damage; failure; glass windows; near-field; numerical modelling
Address
Chiara Bedon: Department of Engineering and Architecture, University of Trieste, 34172 Trieste, Italy
Damijan Markovic, Vasilis Karlos, Martin Larcher: European Commission, Joint Research Centre, 21027 Ispra, VA, Italy
Abstract
Scarce research has been published on crack propagation fracture of flywheels manufactured with carbon fiber-reinforced polymers. The present work deals with a calculation method to determine the conditions for which a crack propagates in the axial direction of the flywheel. The assumptions are: flywheels made with just a single thick ply or ply clustering laminates, oriented following the hoop direction; a single crack is analyzed in the plane defined by the hoop and axial directions; the crack starts close to one of the free edges; its axial length is initially large enough so that its tip is far away from that free edge, and the crack expands the entire circumferential perimeter and keeps its concentric position. The developed method provides information for a good design of flywheels. It is concluded that a fracture-based crack propagation criterion generally occurs at a lower speed than a stress-based criterion. Also, that the evolution of failure with thickness using the fracture criterion is exponential, demonstrating that thin flywheels are relatively not sensitive to crack propagation, whereas thick ones are very prone.
Key Words
analytical stress analysis; composite material flywheel; crack growth; failure criteria; finite elements; linear fracture mechanics
Address
Lluis Ripoll, Pere Maimí, Emilio V. González: 1Mechanical Engineering & Industrial Construction, Universitat de Girona, 17003 Girona, Spain
José L. Pérez-Aparicio: Continuum Mechanics & Theory of Structures, Universitat Politècnica de València, 46022 Valencia, Spain