In this work, the functionally graded honeycomb structures with defects are investigated. It is shown how patterns and locations of defects, as well density gradients, can affect in-plane dynamic crushing behavior honeycombs. Numerical results show that due to missing vertical cell walls, deformation process for transverse-vertical mixing more complicated than pure defects. For honeycombs negative gradient, I-shape band dominant during crushing. However, positive gradient crushed...

The bending responses of functionally graded (FG) nanobeams with simply supported edges are investigated based on Timoshenko beam theory in this article. Gurtin–Murdoch surface elasticity is adopted to analyze the influences stress response FG nanobeam. material properties assumed vary along thickness nanobeam power law. governing equations derived by using minimum total potential energy principle and explicit formulas for rotation angle deflection effects. Illustrative examples implemented...

Abstract In the present work, in-plane dynamic crushing behavior of functionally graded honeycomb structures with missing-wall defects is investigated. To study influences properties on crushing, a density gradient introduced by changing cell wall thicknesses along impact direction. Results show that both deformation mode and energy absorption are sensitive to gradient. However, displays less dependence when impacted at high velocity. Furthermore, effects defect ratios locations discussed....

Encouraged by the highly development of nano piezoelectric structures and demand new energy, this work proposes an energy harvester with porous materials. Based on Biot's elasticity, analytical expressions in thickness-shear mode are derived calculated. The numerical results shows that behaves much better than its alternative nonporous solid-fluid coupling constant affects resonant frequency significantly, but power peak slightly. However, dielectric can influence both peak. Moreover,...

In the present work, a nanoscale piezoelectric beam is developed as an energy harvester. The proposed model can convert flexural vibration to electric energy. Based on surface effect theory, nano considered be composite structure with core and two layers. analytical expressions of are given, numerical calculations conducted. Results show that has important influences performances output power sensitive elastic constant constant. coupling effects material constants examined. physical...

Abstract Irradiance prediction is a vital task in the renewable energy field. Its aim to forecast irradiance or power of photovoltaic plant and thus provide reference for stabilizing grid. In real scenarios, missing data can significantly reduce accuracy prediction. Meanwhile, due unawareness distribution datasets, it difficult choose suitable imputation method before modeling. Also, different methods do not have same good effects on datasets. this article, recurrent neural network with an...

Presented herein is a functionally graded piezoelectric energy harvester using thin cylindrical shell. The torsional mode for the shell studied and effects of parameters on power density are discussed. analytical expressions derived. From results obtained, it can be observed that constant has obvious influences peak value density. Moreover, larger values may obtained by increasing elastic parameter mass This work expected to useful in analysis design as well new kinds systems.

Honeycomb materials have been widely used in architecture, aerospace, and civil engineering recent years. In this work, hexagonal hierarchical honeycombs with regular triangular substructures are studied. Based on the analytical model, expressions of relative density collapse stress derived. Numerical results show that substructure number, aspect ratio, wall angle different influences density. The is sensitive to Deformation modes honeycomb structures depend impact velocities, secondary...

Piezoelectric/piezomagnetic energy harvester has attracted great interest, which can convert magnetic into electric power. However, the challenges are how to provide lasting nanoscale components and avoid inherent brittleness of piezoelectric piezomagnetic materials. Therefore, a nanoporous piezoelectric/piezomagnetic beam with storage circuit is proposed be an in this paper. The treated as sandwich composite piezoelectric/piezomagentic core bulks surface or interface layers. Based on effect...

Nanoporous materials and structures have attracted widespread attention due to their excellent mechanical properties. Based on the surface elasticity, effective Young’s moduli are derived for four typical nanoporous with periodic unit cells. When cross-sectional size reduces nanoscale, modulus is revealed be strongly size-dependent. Both effects of residual stress effective-surface examined. The results indicate that negative can achieved when less than zero. influences shape relationship...

Fracture mechanics is an engineering discipline, which originated from Griffith energy-balance concept. The energy method the most powerful analytical tool for fracture mechanics. Starting principle in crack propagation, quasi-static governing equations and release rate of DCB specimen can be derived by this paper. Finally, some correlative problems are discussed.

In order to explain the water utilization mechanism of Pinus Yunnanensis plantations in Central Yunnan Karst Plateau, SW China, and their adaptive strategies arid karst habitat, authors collected analyzed stable 18 O isotope values stem Bajiang valley, accompanying trees bushes potential sources. The IsoSource model was applied compute probable contribution multiple sources total plant. results show that ecosystem plantations, there exists significant evaporative isotopic fractionation...

Based on empirical electron theory of solid and molecule (EET, Empirical Electron Theory Solids Molecules) ,this paper calculated the Cr1 – xMxN molecular coating’s valence structure phase space coating matrix out interface. By analysing microscopic structure, we discussed alloy elements’ influence this series coatings’ resistance. And found that V elements can significantly increase metal chromium nitride’s were resistance , element Ti takes second place, Al also has some effect.

Based on base forces theory framework, the basic equations of time boundary value problem large elastic deformation in non-conservative systems are defined. According to corresponding relations between generalized and displacements, elasto-dynamics multiplied by virtual quantities, integrated then added algebraically. Considering that both body surface fellow forces, Hamilton-type quasi-variational principles with three kinds variables based established. Then they degenerated. Applying...

To elucidate the relationship between stable isotopes of precipitation (SIP) and extreme drought in Kunming area, based on data GNIP site from 1986 to 2003, line equation is brought forward seasonal change rule are discussed. The isotopic compositions exhibit great diversities different seasons during influences multiple factors, such as monsoon, rainfall amount moisture source others. δ 18 O values rainwater significant variations, average of-10.12‰ rainy season, dry season is-4.5‰, having...