A Contribution to Analytical Solutions for Buckling Analysis of Axially Compressed Rectangular Stiffened Panels

Analytical solution to the buckling problems of stiffened panels subjected to in-plane compressive loads is presented. The total potential energy functional of stiffened panel is obtained by the summation of that of a line continuum and stiffened panel derived from elastic principles of mechanics. Minimizing the resulting equation with respect to deflection coefficient and rearranging gives the expression for obtaining the buckling load of stiffened panel. Exact deflection functions were substituted directly in the new solution and various edge conditions were considered in this analysis. Obtained results were compared with analytical results of previous works. The method is computationally efficient for complex edge conditions and gives high numerical accuracy.

Analisis Pelat Lantai Menggunakan Metode Hirzfeld

At this time construction of the royal house is growing very fast at Batam City. The matter proves that are people's construction is successfully for planning the building at Batam City. Floor Slab Analysis with Hirzfeld Method done for knowing the main deflection coefficient and flexible moment of the floor slabs with different dimensions are have different four cases. After analyzed then, obtain results that are the higher dimension of the floor slab then obtain the higher deflection coefficient and flexible moment also.

Noncoherent Decision Fusion over Fading Hybrid MACs in Wireless Sensor Networks

In this paper, we consider the problem of decision fusion for noncoherent detection in a wireless sensor network. Novel to the current work is the integration of the hybrid multi-access channel (MAC) in the fusion rule design. We assume that sensors transmit their local binary decisions over a hybrid MAC which is a composite of conventional orthogonal and nonorthogonal MACs. Under Rayleigh fading scenario, we present a likelihood ratio (LR)-based fusion rule, which has been shown to be optimal through theoretical analysis and simulation. However, it requires a large amount of computation, which is not easily implemented in resource-constrained sensor networks. Therefore, three sub-optimal alternatives with low-complexity are proposed, namely the weighed energy detector (WED), the deflection-coefficient-maximization (DCM), and the two-step (TS) rules. We show that when the channel signal-to-noise ratio (SNR) is low, the LR-based fusion rule reduces to the WED rule; at high-channel SNR, it is equivalent to the TS rule; and at moderate-channel SNR, it can be approached closely by the DCM rule. Compared with the conventional orthogonal and nonorthogonal MACs, numerical results show that the hybrid MAC with the proposed fusion rules can improve the detection performance when the channel SNR is medium.

ANALYTICAL BENDING SOLUTION OF ALL CLAMPED ISOTROPIC RECTANGULAR PLATE ON WINKLER’S FOUNDATION USING CHARACTERISTIC ORTHOGONAL POLYNOMIAL

The analytical bending solution of all clamped rectangular plate on Winkler foundation using characteristic orthogonal polynomials (COPs) was studied. This was achieved by partially integrating the governing differential equation of rectangular plate on elastic foundation four times with respect to its independents x and y axis. The foundation was assumed to be homogeneous, elastic and isotropic. The governing differential equation was non-dimensionalised to make it consistent. The deflection polynomials functions were formulated. Thereafter, the Galerkin’s works method was applied to the governing differential equation of the plate on Winkler foundation to obtain the deflection coefficient, . Numerical example was presented at the end to compare the results obtained by this method and those from earlier studies. The percentage difference obtained for central deflection of all clamped rectangular plate loaded with UDL using the method and earlier research works for K = 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 are: 0.000042, 0.000052, 0.000043, -0.000011, -0.000068, 0.000001, 0.000001, 0.000001, -0.000001, 0.000000, 0.000001. 0.000033, 0.000035, 0.000033, -0.000018, -0.000072, -0.000003, -0.000003, -0.000003, 0.000002, -0.000002, -0.000001. The result showed that an easy to use and understandable model was developed for determination of deflections of all clamped rectangular plates on Winkler’s elastic foundation using principle of COPs. http://dx.doi.org/10.4314/njt.v36i3.9

Coherent Distributed Detection Using Inhomogeneous Sensors Under Local Power Constraint

In this paper, we consider the problem of local power constrained coherent distributed detection over fading multi-access channel (MAC). The deflection coefficient maximization (DCM) is used to optimize the performance of fusion system under local power constraint of sensors. We use the statistical information of channel gain to obtain the deflection coefficient of the detection statistics at the fusion center. We derive the closed-form solution to the considered optimization problem. Monte-Carlo simulations are carried out to verify the performance of the proposed method. Simulation results show that the proposed method could significantly improve the detection performance of the fusion system under local power constraint and low signal-to-noise ratio (SNR).

Preparation and Characterization of Flexible Polyurethane Foams from Palm Oil-Based Polyol

Flexible polyurethane (PU) foams were prepared by replacing commercial petroleum-based polyether polyol with palm oil-based polyol up to 50 wt%. Palm oil was converted to polyol by transesterification reaction with glycerol using calcium oxide as a catalyst. PU foams were then prepared from reaction between mixtures of palm oil-based polyol and petrochemical polyols with toluene diisocyanate (TDI) using water as blowing agent. The morphology and physical-mechanical properties including apparent density, indentation hardness, compressive deflection coefficient or support factor, tensile strength, and tear strength of the prepared foams were characterized and compared to those of reference foam prepared using only conventional petrochemical polyols. Scanning electron microscopy (SEM) indicated that the cellular structures of all the prepared foams were semi-open and the cell size decreased with higher amount of palm oil-based polyol. The apparent densities and the compressive deflection coefficient of the PU foams increased with the increasing amount of palm oil-based polyol, while the indentation hardness showed the opposite tendency. Furthermore, the obtained foam modified with palm oil-based polyol of 20 wt% were found to have the highest tensile and tear strengths.