In this study, the pre-buckling and post-buckling behaviors of layered composite plates which were made of woven carbon fiber fabric with a circular hole in the middle were investigated experimentally and numerically. Firstly, load-displacement graphs of composite plates with different hole diameters were experimentally obtained under compressive load. Then the numerical load-displacement graphs of the plates were found with the ANSYS package program which used the finite element method. As a result, after linear buckling experimental and numerical results were found to be compatible with each other. In addition, damage behavior of plates after buckling with the aid of Tsai-Wu damage criterion was obtained similar to experimental results. The increase in hole diameter did not change the load-displacement behavior characteristics of the plates after buckling. However, it has reduced maximum damage load and maximum failure displacement. The stress at the perimeter of the hole increased significantly with the increase of the vertical displacement with immediately after the buckling but later was not significantly affected by this increase.
This work considers the analysis of a cracked semi-infinite cylinder and a finite cylinder. Material of the cylinder is assumed to be linearly elastic and isotropic. One end of the cylinder is bonded to a fixed support while the other end is subjected to axial tension. Solution of this problem can be obtained by superposition of solutions for an infinite cylinder subjected to uniformly distributed tensile load at infinity (I) and an infinite cylinder having a penny-shaped rigid inclusion at z = 0 and two penny-shaped cracks at z = ±L (II). General expressions for the perturbation problem (II) are obtained by solving Navier equations with Fourier and Hankel transforms. When the radius of the inclusion approaches the radius of the cylinder, the end at z = 0 becomes fixed and when the radius of the cracks approach the radius of the cylinder, the ends at z = ±L become cut and subject to uniform tensile load. Formulation of the problem is reduced to a system of three singular integral equations. By using Gauss–Lobatto and Gauss–Jacobi integration formulas, these three singular integral equations are converted to a system of linear algebraic equations which is solved numerically. 相似文献
The performance of cascaded low-loss (<3.5 dB) 256/spl times/256 three-dimensional microelectromechanical system (3-D MEMS) photonic cross-connects (PXCs) is experimentally investigated in a recirculating loop. After 60 transitions through the PXC, a power penalty of 1.7 dB is observed, which is attributed to the accumulation of the low polarization-dependent loss in the optical switch. The use of 3-D MEMS PXCs as a wavelength-selective switch (WSPXC) for transparent all-optical networks is also demonstrated. Measured Q-factors for all 16 100-GHz-spaced wavelengths at 10 Gb/s over eight spans of 75-km single-mode fiber and eight transitions through the WSPXC nodes are better than 17 dB. 相似文献
In the present study, qualitative simulation model of reservoir and genetic algorithm optimization model were combined based on fuzzy logic to determine the trade off curve with stochastic quantitative and qualitative objectives. According to contradictory utilities of decision makers with respect to the obtained optimum trade off curve, a model of group conflict resolution was developed in order to determine the best point on the trade off curve from the perspective of decision makers. Using the outcome of conflict resolution model which was indicative of acceptable water quality for all decision makers, the optimization model was re-run, and time series of monthly water opeartion was determined for the agreed quality of beneficiaries. Finally, with the aim of formulating timely policies of operation of the reservoir, the use of probabilistic support vector machines that have the ability to create output possibilities was suggested. The proposed model was used for the operation of 15-Khordad Dam Reservoir, Iran. The results demonstrate the efficiency and accuracy of the fuzzy optimization model as well as the importance of using group conflict resolution model to provide the utility of decision makers in the operation of the reservoir.
We describe the development of a highly specific enzyme-based fluorescence resonance energy transfer (FRET) assay for easy and rapid detection both in vitro and in vivo of Bacillus spp., among which are the members of the B. cereus group. Synthetic substrates for B. anthracis proteases were designed and exposed to secreted enzymes of a broad spectrum of bacterial species. The rational design of the substrates was based on the fact that the presence of D-amino acids in the target is highly specific for bacterial proteases. The designed D-amino acids containing substrates appeared to be specific for B. anthracis but also for several other Bacillus spp. and for both vegetative cells and spores. With the use of mass spectrometry (MS), cleavage products of the substrates could be detected in sera of B. anthracis infected mice but not in healthy mice. Due to the presence of mirrored amino acids present in the substrate, the substrates showed high species specificity, and enzyme isolation and purification was redundant. The substrate wherein the D-amino acid was replaced by its L-isomer showed a loss of specificity. In conclusion, with the use of these substrates a rapid tool for detection of B. anthracis spores and diagnosis of anthrax infection is at hand. We are the first who present fluorogenic substrates for detection of bacterial proteolytic enzymes that can be directly applied in situ by the use of D-oriented amino acids. 相似文献
Fracture toughness of single edge notched fiber reinforced composite plates is investigated experimentally. Load–displacement curves for unidirectional carbon fiber/epoxy resin reinforced composite plates are obtained experimentally under tensile load. Fracture toughness is obtained by determining failure loads. For numerical study, ANSYS is used. Material properties of laminates are calculated with classical laminated plate theory and applied to the finite element model by using plane element. Stiffness matrix of laminates is determined and shell element is chosen for numerical solution. Critical stress intensity factors are calculated with Displacement Correlation Method under experimental failure load conditions. 相似文献
An InGaAsP multiquantum-well traveling-wave electroabsorption modulator is demonstrated with high extinction ratio and modulation efficiency. By designing a strain-compensated quantum-well active region with traveling-wave design, high saturation power (>14 dBm) for >20-GHz high-speed performance (1.5 dB drop at 20 GHz) is achieved. Due to high modulation efficiency (>30 dBN for 0 to 1 V 40-dB extinction ratio in 2 V), error free 10-Gb/s operation with 1 Vp-p driving voltage is obtained. By comparing codirections and counterdirections of optical and microwave interactions, pulse generation at 40 GHz shows that the traveling-wave performance has an advantage for short pulses with high-power output, where pulsewidth as short as 4.5 ps is obtained in this kind of device 相似文献