Dynamic Forces of Swaying Human and Responses of Temporary Demountable Grandstand Based on Experiment and Simulation

Modern temporary demountable structures must be designed to withstand the dynamic forces which generated by crowd occupants. The human forces and that cause the dynamic responses of structure have become an important research topic. In this paper, the human swaying forces and responses of temporary demountable grandstand are studied through an experimental program. The dynamic forces that were induced by participants who have swayed 0.5–1.8 Hz are recorded by a triaxial human biomechanics force plate, and the structural dynamic responses of a temporary grandstand occupied twenty swaying human are investigated. The constraint parameters of swaying force model which derives from a semiempirical formula are developed and can be represented for crowd. Crowd can able to induce excessive lateral vibration of structure due to the lower frequency of temporary grandstand and make them in panic. The dynamic responses of a large temporary grandstand are predicted by finite element method, and the results show that a person was considered as a load with stiffness and damping, and the structural lateral dynamic responses are higher than the model of person just only considered as load.

The sinkage characteristics and the supporting capacity of a submerged floating vehicle driving in deep soft terrains

A submerged floating vehicle, which is utilized in deep soft terrains, has a superior trafficability to those of traditional vehicles. This study focuses on understanding and improving the sinkage characteristics of a submerged floating vehicle travelling on deep soft clay. The factors which influence the sinkage characteristics were analysed, and a soil bin experimental model was established using the similarity theory. A series of experiments was designed for carrying out tests on the sinkage with respect to the pressure, the sliding speed, the aspect ratio and the moisture content of the soil. The experimental results show that the sinkage of the floating device sliding increased with increasing moisture content of the soil. They also show that the sinkage increases with increasing pressure and decreases with increasing aspect ratio of the floating device. By analysing the problems and the challenges which exist in an empirical formula or a semiempirical formula when facing the sinkage of a floating device, a support vector machine for a regression model is proposed in order to construct a multiple non-linear regressive prediction model using experimental data. Further evidence was provided to substantiate the merits of the application of the support vector regression method when dealing with the issue of predicting the sinkage.

CLUSTER RADIOACTIVITY IN TRANS-TIN REGION USING SEMIEMPIRICAL FORMULA

A semiempirical formula with only three parameters for calculating the logarithm of half-lives of heavy particle emission from a radioactive nucleus is recently proposed. The constants in the formula were obtained by fitting the available data in the trans-actinide region. The suitability of the formula in trans-tin region is studied here. The present study reveals that the semiempirical formula with only three parameters is not agreeing well with other theoretical models in the trans-tin region. Hence, one of the constants proposed earlier which acts a scaling constant is suitably replaced by a quadratic equation. The results are compared with analytical superasymmetric fission model and Shanmugham and Kamalakaran model. The semiempirical formula with new set of constants are found to have a better agreement with the available theoretical results.

Investigation of Dominant States in Dielectronic Recombination Rates for Fe-Ions

Dielectronic recombination (DR) cross sections and rate coefficients are calculated for the isonuclear sequence FeZ+, with Z = 21, 20, 19, 18, 17, and 16, in which L-shell (2p-) excitations are involved during the initial capture. Most of the dominant transitions with Δn ≠ 0, using angular momentum average (AMA) approximation, are considered. It is found that the states 3pnd and 3dnd contribute most to the rate coefficients. In addition, the rates are found to increase with increasing number of electrons in the ion, (i. e. as Z decreases). Moreover, the rate coefficients, αDR, for the studied ions are found to peak around the same energy (kT = 30 Ry). A semi-empirical formula for the total rates α is obtained for the 2p-excitation with Δn ≠ 0 in the case of FeZ+ ions. On comparing both results, the explicit calculations and the results obtained from the semiempirical formula, good agreement is found. The available results for αDR may be considered as a database for future comparison with experimental and theoretical calculations. Comparison of our results with other results show the effect of the empirical rate formula.