http://dspace.nbuv.gov.ua:80/handle/123456789/173571 2026-04-22T10:05:28Z http://dspace.nbuv.gov.ua:80/handle/123456789/173601 Modeling of Nonlinear Isolation System Based on Bouc-Wen Differential Model Peng, Z.; Zhou, C.G. A feedforword neural network of multi-layer topologies for systems with hysteretic nonlinearity was constructed based on the Bouc-Wen differential model. The proposed model not only reflects the hysteresis force characteristics of the Bouc-Wen model, but can also determine the corresponding parameters. The simulation results demonstrate that the restoring force-displacement curve hysteresis loop closely represents real curves. The trained model can accurately predict the time response of the system. By comparing results obtained by the proposed model with real responses, the model was validated in the presence of noise and exhibits increased modeling precision, good generalizability and anti-interference capability. 2017-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/173600 Effect of Braiding Angle on the Impact and Post-Impact Behavior of 3D Braided Composites Yan, S.; Guo, L.Y.; Zhao, J.Y.; Lu, X.M.; Zeng, T.; Guo, Y.; Jiang, L. In this study, the impact and post-impact behavior of three-dimensional (3D) four-directional carbon/epoxy braided composites having different braiding angles were investigated. The same impact energy (45 J) was applied to the specimens. The post-impact mechanical properties of the materials were performed by compression after impact (CAI) testing, and the processes were monitored by the acoustic emission (AE) technique. Results showed that the specimens with larger braiding angle sustained higher peak loads, and smaller impact damage area, mainly attributed to a more compact space arrangement. The CAI strength and damage mechanism were found to be mainly dependent on the axial support of the braiding fiber tows. Increasing the braiding angle of the composites, the CAI strength was reduced, and the damage mode of the composites was changed from transverse fracture to shear one. Combining AE parameters and CAI curves allows one to characterize the failure process, thereby enabling fracture analysis of the materials under study. 2017-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/173599 Experimental and Numerical Analysis of the Edge Effect for Corrugated and Honeycomb Fiberboard Hua, G.J.; Shen, Y.; Zhao, D.; Xie, Y. As the two typical structural paper packaging materials, corrugated fiberboard and honeycomb paperboard occupy an important position in the field of logistics packaging. Up to now, numerous studies were focused on the properties of the above sandwich paperboards. However, the issue of their edgewise compressive strength has reached no consensus yet. The objective of this study is to investigate the edge effect and the influence on edgewise compressive strength of the two sandwich paperboards by experimental and numerical simulation methods. Firstly, the standard size specimens of the two sandwich paperboards were made based on the machining direction (MD) and crossmachining direction (CD), and the edgewise compressive strength experiments were carried out. Secondly, the finite element models of corrugated fiberboard and honeycomb paperboard were constructed using the same material, comprehensive weight and thickness, while the numerical assessment on edgewise compressive strength of CD and MD of the models were analyzed, respectively. Finally, measures to restrain the edge effect were taken, and the edge enhancement finite element models of the two paperboards were eleborated. The buckling analysis was carried out based on the numerical method. The results obtained suggest that the edge effect is one of the major factors controlling the edgewise compression strength ofcorrugated fiberboard and honeycomb paperboard. 2017-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/173598 Numerical Simulation of Flexible Riser under Torsion Liu, M.S.; Liu, X.W.; Li, J.Y.; Ju, J.S. The 10-layer unbonded flexible riser is modeled with parametric modeling technology in FEM and the model is imported into ABAQUS to simulate the riser’s mechanical behavior under the load condition: torsion. FEM model considering material nonlinearity and nonlinear boundary conditions (the interaction between layers) has been set to simulate the structure of riser exactly. Based on the detailed finite element model, the influence of friction coefficient on the calculation results of the riser under torsion force is studied. The computation demonstrates that there is great difference between layers and the tension armor (consisted of steel strips) is the main bearing layer. Besides, the friction coefficient has great influence on the result of the calculation. 2017-01-01T00:00:00Z