Empirical estimates of the fundamental frequency of tall buildings vary inversely with their height, a dependency not exhibited by the various familiar models of beam behavior. This paper examines and explains this apparent discrepancy by analyzing the consequences of using two models to estimate such natural frequencies: A two-beam model that couples the bending of a classical cantilever to th...

The complete stress field, including the microstress, the moment-stress, and the line forces are derived for the pure bending of a rigid-plastic beam of rectangular cross-section in the model of strain-gradient plasticity. The workless spherical parts of the microstress and the moment-stress tensors are incorporated in the analysis. Their determination is shown to be of importance for the fulfi...

The use of a three dimensional Discrete Element Method (DEM) is proposed to study concrete submitted to rock-fall impacts. The model has already been validated through quasi-static, as well as dynamic simulations (SHPB tests). The simulation of four-point beam bending tests has validated the introduction of the reinforcement in the model. With this approach all the local parameters can be ident...

The modified mapping-collocation (MMC) method is applied to the problem of an isotropic curved beam with a circumferential crack under pure bending moment. Using least squares method to solve the overdetermined system of boundary condition equations causes numerical difficulties. Alternatively zeroth-order Tikhonov regularization is applied to solve the system. The regularization technique appe...

Finite element analysis facilitates optimal design of MEMS/NEMS devices for reliability. The same is used here to analyze the effect of types of fractal rough surfaces on static response of nanobeams Three-dimensional rough surfaces are generated using modified two variable Weierstrass-Mandelbrot function with given fractal parameters. Beam with various fractal roughness are modelled to observe...

A hybrid finite–discrete element method (FDEM) is proposed to investigate dynamic pure-mode-II fracture behaviors. The transition of continuum discontinuum was applied the FDEM through use three modes, so that whole process could be modeled naturally. then employed model behavior rock during a four-point bending test with prefabricated notch. results showed initiated from tip notch under relati...

Displacement finite element models of various beam theories have been developed using traditional finite element interpolations (i.e., Hermite cubic or equi-spaced Lagrange functions). Various finite element models of beams differ from each other in the choice of the interpolation functions used for the transverse deflection w, total rotation φ and/or shear strain γxz, or in the integral form u...

the welding in cold formed areas is not only an open question for statically loaded sections (brittle fracture) but also for dynamically loaded structures (fatigue resistance). a lot of structures are subjected to dynamic loadings and unfortunately very little information about the influence of welding in the cold formed areas on fatigue resistance is available. in order to establish the fatigu...

Observations of the self-deflection effect for an asymmetrical continuous-wave laser beam in sodium vapor are described, and comparisons based on theoretical calculations are made. A self-bending angle as large as eight diffraction widths was recorded, and strong attenuation of the on-axis radiation due to self-bending was measured. At -200'C the self-deflection angle increased linearly with be...

using computation software to simulate fracture behaviors of structures can shorten the time to estimate safety of engineering structures and reduce a lot of cost of experiment. However three dimensional numerical simulation for fracture process is a challenging issue, because the convergence and accuracy are not easily obtained and high computational cost is generated. In this paper, three new...