Evaluation of Bolt-hole Elongation Stiffness for the Stiffness Prediction of Cold-formed Steel Bolted Moment-connections

Cold-formed steel bolted moment-connections cannot be considered as rigid because of localised in-plane elongation of the bolt-holes due to bearing of the bolt-shank against the bolt-hole. To therefore calculate the rotational stiffness of such bolted moment-connections, it is necessary to know the load-extension characteristics of bolt-hole elongation. In this paper, a non-linear large- displacement elasto-plastic finite element idealisation of a plain bolt-shank in bearing against a bolt-hole is presented. Graphs of load against bolt-hole elongation are plotted that show good comparison with laboratory test results. A proposed modification of the results allows for the results of a fully-threaded bolt-shank to be predicted. The bolt-hole elongation stiffness so obtained is the main parameter required for the analysis of cold-formed steel frames that use such bolted moment-connections for the joints

Reka bentuk untuk kestabilan struktur

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Development of aluminum alloy compounds for electroluminescent light sources

Aluminum alloy compounds as wide band gap semiconductors for electroluminescent light source

Influence of Deformed Metal Decking Composite Floors to Beam-column Connections

A series of tests designed to investigate the interaction of a variety of different steel beam to column connection details with a composite metal deck floor is described. The main emphasis is on assessing the connections\u27 moment capacity, rotational stiffness and rotation capacity. The full details of the experimental behaviour of the flush end plate and partial depth end plate connections will be described in this paper. A simple method for moment capacity calculation based on the test results is proposed herein

Multiband theory of quantum-dot quantum wells: Dark excitons, bright excitons, and charge separation in heteronanostructures

Electron, hole, and exciton states of multishell CdS/HgS/CdS quantum-dot quantum well nanocrystals are determined by use of a multiband theory that includes valence-band mixing, modeled with a 6-band Luttinger-Kohn Hamiltonian, and nonparabolicity of the conduction band. The multiband theory correctly describes the recently observed dark-exciton ground state and the lowest, optically active, bright-exciton states. Charge separation in pair states is identified. Previous single-band theories could not describe these states or account for charge separation.Comment: 10 pages of ReVTex, 6 ps figures, submitted to Phys. Rev.

Simplified buckling analysis of skeletal structures

Accepted versio

Electron and hole states in quantum-dot quantum wells within a spherical 8-band model

In order to study heterostructures composed both of materials with strongly different parameters and of materials with narrow band gaps, we have developed an approach, which combines the spherical 8-band effective-mass Hamiltonian and the Burt's envelope function representation. Using this method, electron and hole states are calculated in CdS/HgS/CdS/H_2O and CdTe/HgTe/CdTe/H_2O quantum-dot quantum-well heterostructures. Radial components of the wave functions of the lowest S and P electron and hole states in typical quantum-dot quantum wells (QDQWs) are presented as a function of radius. The 6-band-hole components of the radial wave functions of an electron in the 8-band model have amplitudes comparable with the amplitude of the corresponding 2-band-electron component. This is a consequence of the coupling between the conduction and valence bands, which gives a strong nonparabolicity of the conduction band. At the same time, the 2-band-electron component of the radial wave functions of a hole in the 8-band model is small compared with the amplitudes of the corresponding 6-band-hole components. It is shown that in the CdS/HgS/CdS/H_2O QDQW holes in the lowest states are strongly localized in the well region (HgS). On the contrary, electrons in this QDQW and both electron and holes in the CdTe/HgTe/CdTe/H_2O QDQW are distributed through the entire dot. The importance of the developed theory for QDQWs is proven by the fact that in contrast to our rigorous 8-band model, there appear spurious states within the commonly used symmetrized 8-band model.Comment: 15 pages, 5 figures, E-mail addresses: [email protected], [email protected]

Assessment of progressive collapse in multi-storey buildings

Accepted versio