Tytuł Data publikacji Autor
A novel sandwich composite footbridge is described in this paper, for the first time after it has been put into operation over the Radunia River in the Pruszcz Gdański municipality. This paper presents results of dynamic tests and describes technical monitoring of the footbridge. The dynamic tests were conducted to estimate pedestrian comfort and were compared with the ones from numerical simulations made in the environment of Finite Element Method. A discussion of the obtained results is made then. The characteristics and capabilities of the network of sensors spread over the bridge to monitor its long-term behavior are described.
2020
Jacek Chróścielewski,
Mikołaj Miśkiewicz,
Łukasz Pyrzowski,
Magdalena Rucka,
Bartosz Sobczyk,
Krzysztof Wilde,
Błażej Meronk
The article presents numerical simulations, dynamic in situ load tests and a structural health monitoring (SHM) system installed in a suspended on a single cable footbridge. Numerical simulations performed prior to construction indicated the possibility of structural dynamics problems, finally confirmed in the course of dynamic test loading. In the dynamic load course the bridge deck developed vibrations displaying accelerations up to 4.5 m/s2. Such footbridge behavior causes unacceptable discomfort to the users and risk of structural damage. The tests brought about the need for repair works and the use of a monitoring system to increase operational safety of the object.
2020
Mikołaj Miśkiewicz,
Łukasz Pyrzowski,
Krzysztof Wilde
In the framework of the simplified linear Gurtin–Murdoch surface elasticity we discuss a singularity of stresses and displacements in the vicinity of a mode III crack. We show that inhomogeneity in surface elastic properties may significantly affect the solution and to change the order of singularity. We also demonstrate that implicitly or explicitly assumed symmetry of the problem may also lead to changes in solutions. Considering various loading and symmetry conditions we show that the stresses may have logarithmic or square root singularity or be bounded in the vicinity of a crack tip.
2020
Nikolai Gorbushin,
Victor Eremeev,
Gennady Mishuris
We discuss two examples of beam-lattice metamaterials which show attractive mechanical properties concerning their enriched buckling. The first one considers pantographic beams and the nonlinear solution is traced out numerically on the base of a Hencky’s model and an algorithm based on Riks’ arc-length scheme. The second one concerns a beam-lattice with sliders and the nonlinear solution is discussed in analytic way and, finally, extended to the case of uniform in-plane tension. Some concluding remarks draw possible future developments and challenges.
2020
Victor Eremeev,
Emilio Turco
This research predicts theoretically post-critical axial buckling behavior of truncated conical carbon nanotubes (CCNTs) with several boundary conditions by assuming a nonlinear Winkler matrix. The post-buckling of CCNTs has been studied based on the Euler-Bernoulli beam model, Hamilton’s principle, Lagrangian strains, and nonlocal strain gradient theory. Both stiffness-hardening and stiffness-softening properties of the nanostructure are considered by exerting the second stress-gradient and second strain-gradient in the stress and strain fields. Besides small-scale influences, the surface effect is also taken into consideration. The effect of the Winkler foundation is nonlinearly taken into account based on the Taylor expansion. A new admissible function is used in the Rayleigh-Ritz solution technique applicable for buckling and post-buckling of nanotubes and nanobeams. Numerical results and related discussions are compared and reported with those obtained by the literature. The significant results proved that the surface effect and the nonlinear term of the substrate affect the CCNT considerably.
2020
Mohammad Malikan,
Victor Eremeev
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