Effect Of Stiffness Distribution Research Articles

Effects of flexural stiffness on constraints of imposed deformations in reinforced concrete structures

Constraints from imposed deformations are external constraints that occur, for example, through differential settlements in statically indeterminate systems and are directly proportional to stiffness. The flexural stiffness of reinforced concrete structures is a complex issue that is considerably dependent on concrete cracking. Considering constraints in the design is not easy because many variables must also be considered. The constraint value depends on loading conditions with favourable or unfavourable effects. To obtain realistic results, experimental investigations on constraints derived from differential settlements are conducted. The degree of reinforcement, slenderness, concrete strength, and the effect of constraints are investigated as parameters. The tests showed that the constraint was reduced nearly constantly from the beginning of loading and was no longer present when the maximum load was reached. For this reason, the non-constant stiffness and the effect of stiffness distribution on the internal force distribution could be identified.

Effects of stiffness distribution and spanwise deformation on the dynamics of a ray-supported caudal fin

Using a fluid-structure interaction model, we study the effect of ray stiffness distribution on the deformation and performance of a caudal fin. By prescribing a simple swaying motion, our results show that through passive structural deformation alone it is possible to reproduce some complicated fin movements (e.g. the cup and ‘W’-shape deformations) observed in real fish. Moreover, it has been numerically shown that, compared with a fin with uniform ray stiffness, at the same (average) ray stiffness fins with nonuniform stiffness distribution may achieve further performance enhancement, e.g. increase in propulsion efficiency and decrease in lateral force generation. This is attributed to spanwise deformations caused by phase differences between different rays.

An effective computer modelling approach to the study of aeroelastic characteristics of an aircraft composite wing with high aspect ratio

Static aeroelastic and flutter characteristics of an aircraft composite wing with high aspect ratio were analysed by an effective Computational Fluid Dynamics and Computational Structure Dynamics coupled method. Effects of stiffness distribution on aeroelastic characteristics were considered. Honeycomb core sandwich composite was considered to be equivalent to an orthotropic material by stiffness and inertance equivalent method to allow highly efficient numerical simulation, which was used for analysis of bending and torsional stiffness distribution. The results showed that the redistributed aerodynamic load leads to a decrease of pressure difference between the upper and lower airfoils. The flutter speed of the composite wing is near 0.64 Ma. Both bending and torsional stiffness increases with a small increase of beam size. Stiffness of the wing root has a major influence generally on the static aeroelastic characteristics. Both the lift coefficient and the loss percent decrease with a small increase of beam size. Effects of stiffness distribution on frequency are not obvious. Flutter speed remains close to the initial value when the beam size is changed.

Finite element analysis about effects of stiffness distribution on stresses and elastic strain energy near the triple junction in a tricrystal

A three-dimensional anisotropic finite element analysis was performed to investigate stresses and elastic strain energy in the models that were taken from a copper tricrystal. The purpose was to determine how the stiffness distribution affected the stress-state near the triple junction. The finite element results show that stresses and elastic strain energy density near the triple junction depend greatly on the stiffness distribution in tricrystal models. Because the bending and twisting deformation occurs when the tricrystal is uniaxially loaded, stresses at surfaces are significantly different from the interior stresses near triple junction.