Total Mass Of Structure Research Articles

Topology Optimization of Metal and Carbon Fiber Reinforced Plastic (CFRP) Laminated Battery-Hanging Structure.

This study addressed the topology optimization of a carbon fiber reinforced plastic (CFRP) laminated battery-hanging structure of an electric vehicle. To accommodate parameterization for thickness and orientation of CFRP materials, the discrete material and thickness optimization (DMTO) technique was adopted. To include metal material as a reinforcement structure into the optimization simultaneously, the DMTO technique was extended here to achieve concurrent optimization of CFRP thickness topology, CFRP orientation selection and the topology of the metal reinforcement plate. Manufacturing constraints were applied, including suppressing intermediate void across the thickness direction of the laminate, contiguity constraint and the symmetrical layers. Sensitivities of the objective function were derived with respect to design variables. To calculate analytical sensitivities, finite element analysis was conducted and strain vectors were exported from a commercial software (ABAQUS) into a mathematical analysis tool (MATLAB). The design objective was to minimize the local displacement subject to the constraints of manufacturing and mass fraction. The mechanical performance of the optimized CFRP structure was compared with the original steel structure. To validate the optimization results, a prototype of the CFRP battery-hanging structure was fabricated and experimental testing was conducted. The results show that the total mass of the CFRP battery-hanging structure was reduced by 34.3% when compared with the steel one, while the mechanical property was improved by 25.3%.

Study of the unusable liquid propellant residues evaporation processes parameters in the tanks of the launch vehicle expended stage in microgravity

A method is proposed for studying the evaporation process of unusable rocket propellant (RP) residues in an expended stage (ES) under weightless conditions. Two options were considered as boundary conditions for liquid RP residues: a) liquid drop distribution in N identical drops, whose surface decreases during evaporation and b) the liquid distribution in the lower tank bottom and the mirror presence, whose area decreases during evaporation. A high-temperature stream of hydrogen peroxide decomposition products is used as a heat carrier (HC) fed to the fuel tank. The physical and mathematical model of the liquid evaporation process is based on the first thermodynamics law. Based on the analysis of the Frud and Grashof criteria, the assumption that there is no convection movement inside the drop (Rayleigh number is less than critical) for both boundary conditions variants, the heat transfer coefficient of the gas-vapor mixture (GVM) produced in the tank is determined due to the regression dependence obtained under ground conditions as a function of the Nusselt, Reynolds and Prandtl numbers. GVM parameters for the considered boundary conditions variants and the proposed physical mathematical model are compared with the results obtained earlier for the boundary conditions variant of uniform fluid distribution over the inner tank wall (third boundary conditions variant) and the boundary layer theory usage based on integral impulses, energy and diffusion ratios. The thermophysical GVM parameters and the GVM exhaust velocity for oxygen and kerosene are provided for two boundary conditions types, using the example of Soyuz-2.1.v type fuel tanks. The total mass of the RP residues evaporation system structure is less than 1.3% of the total “dry” ES design mass.

Experimental study on models of cylindrical steel tanks under mining tremors and moderate earthquakes

The aim of the study is to show the results of complex shaking table experimental investigation focused on the response of two models of cylindrical steel tanks under mining tremors and moderate earthquakes, including the aspects of diagnosis of structural damage. Firstly, the impact and the sweep-sine tests have been carried out, so as to determine the dynamic properties of models filled with different levels of liquid. Then, the models have been subjected to seismic and paraseismic excitations. Finally, one fully filled structure has been tested after introducing two different types of damages, so as to verify the method of damage diagnosis. The results of the impact and the sweep-sine tests show that filling the models with liquid leads to substantial reduction in natural frequencies, due to gradually increasing overall mass. Moreover, the results of sweep-sine tests clearly indicate that the increase in the liquid level results in significant increase in the damping structural ratio, which is the effect of damping properties of liquid due to its sloshing. The results of seismic and paraseismic tests indicate that filling the tank with liquid leads initially to considerable reduction in values of acceleration (damping effect of liquid sloshing); however, beyond a certain level of water filling, this regularity is inverted and acceleration values increase (effect of increasing total mass of the structure). Moreover, comparison of the responses under mining tremors and moderate earthquakes indicate that the power amplification factor of the mining tremors may be larger than the seismic power amplification factor. Finally, the results of damage diagnosis of fully filled steel tank model indicate that the forms of the Fourier spectra, together with the frequency and power spectral density values, can be directly related to the specific type of structural damage. They show a decrease in the natural frequencies for the model with unscrewed support bolts (global type of damage), while cutting the welds (local type of damage) has resulted in significant increase in values of the power spectral density for higher vibration modes.

Control of subduction rate on Tonga-Kermadec arc magmatism

Dehydration/melting of oceanic crusts during returning to the mantle in subduction zones are related to origin of arc lavas. The factors that influence arc magmatism include compositions of the subducting slabs, mantle wedge and subduction rates. However, distinguishing these factors remains difficult and highly debated. Subducting rate is related to the total mass of inputs and controls thermal structure, thus plays a crucial role in arc magmatism. Here we explore the relationships between geochemical variations of arc lavas and convergence rates (increasing from 46 mm/a to the south to 83 mm/a to the northward) in the Tonga-Kermadec arc system. Data of geochemistry for lava samples from nine islands of this arc system are collected and compiled to investigate the role of subduction rate in arc magmatism. Lavas from the northern Tonga arc with a faster subduction rate show broadly lower concentrations of TiO 2 and highfield-strength elements (HFSEs, e.g. Nb, Ta, Zr, Hf), and higher Ba/Th, U/Th ratios than the Kermadec Arc to the south. Some of the Kermadec lavas show the highest values of Th/Nb ratio. We suggest that the northern Tonga arc with a higher subduction rate has been influenced by a stronger role of subductionreleased fluid, which results in stronger large-ion-lithophile elements (LILEs) and relatively weaker HFSEs contribution. It is interpreted that faster subduction rate tend to create a cooler subduction zone, leading to stronger dehydration subduction slab contribution with, thus, higher LILE/HFSE ratios of arc lavas. The conclusion contributes to a better understanding of arc magmatism, and ultimately the long-term chemical differentiation of the Earth. More supplementary geochemical data along Tonga-Kermadec arc and tests in other arcs are needed.

Study of Far Infrared Nebula at Declination +53° (J2000) In Iras Map

In this present work we studied the flux density variation, calculate temperature, dust mass and finally Jean’s mass of structure using data reduction software ALADIN2.5. Our aim was to test whether this region is star forming or not. Sky view observatory was used for the search of isolated nebular structure in the far infrared (100 μm and 60 μm) in IRAS (Infrared Astronomical Satellite) catalogue. Stellarium software was used to find coordinate of the structure. A far infrared dust structure (about ~ 11.99 × 3.14 pc.) at Right Ascension (J2000):01h 51m 56.02s Declination (J2000): +53deg 27m 39.0s found at the distance of about 550 pc. The dust color temperature was found to lie in the range 18.02 K to 39.56 K. An offset of about 21 K suggests that the structure is not independently evolved, discrete source may play significant role in structure formation mechanisms. The study of flux variation along major and minor axis of structure showed that mass is concentrate at the center of structure. The total mass of the gas structure was found to be about 1.1432× 1031Kg. The Jeans mass was found to be 1.17 x 1033Kg, more than that of the total mass of the structure, suggest no clue of star formation.The Himalayan Physics Vol. 6 & 7, April 2017 (76-79)

Comparing binary systems from rotating parent gas structures with different total masses

In this paper we continue the investigation reported by \cite{RMAA} concerning the morphology of binary configurations obtained via the collapse of rotating parent gas structures with total masses in the range of M$_T$= 1 to 5 M$_{\odot}$. Here we extend the mass range and consider the collapse of two uniform gas clumps of M$_T$= 50 and 400 M$_{\odot}$, so that they also rotates rigidly in such a way that its approximate virial parameter takes the values of 0.5, 1.5, and 2.5 and their collapse is induced initially by implementing an azimuthal mass perturbation. To assess the effects of the total mass of the parent gas structure on the nature of the resulting binary configurations, we also consider the collapse of two cores of M$_T$= 1 and 5 M$_{\odot}$. We calculate the collapse of all these parent gas structures using three values of the ratio of thermal energy to potential energy and for two values of the mass perturbation amplitude. We next calculate the binary separations, masses and integral properties of the binary fragments and present them in terms of the total mass of the parent structure. For most of our models, we finally calculate the $\beta$ extreme value, so that a model with a slightly higher $\beta$ value would no longer collapse.

B201 磁気浮上を用いた制震装置の開発(OS7 磁気浮上・磁気軸受の制御1)

This study expresses a novel active vibration control method for a house structure by using magnetic levitation. The magnetic levitation system is easy to install to the ceiling because there is no need to use linear guides or bearings. In this study, a magnetic levitation device is attached to the iron plate fixed firmly to ceiling of the structure and it will levitate when a vibration occurs. The total mass of structure will be decreased while levitating, resulting in the change of its natural frequency. Moreover, an efficient vibration control method is examined. Finally the results of experiments are shown to confirm its feasibility.

Structural Design of Machine Tool Bed Based on Dynamic ANSYS

This paper attempts to use a simple and practical method based on the finite element theory for the optimal structural design of machine tool bed. The higher is the natural frequency of structure, the better are static and dynamic structural stiffness. Dynamics finite element model of CA6136 machine tool bed has been established with the finite element analytic technique in order to improve the dynamic characteristics. Then, two improved bed design schemes based on unit structure (US) are presented and analyzed by comparison using natural frequency and the total mass of structure as target. The simulation results indicate that the method is simple, effective and feasible. The method also can be applied to other dynamic structural design.