Steady Turning Stability of Partially Filled Tank Vehicles With Arbitrary Tank Geometry

1989 ◽  
Vol 111 (3) ◽  
pp. 481-489 ◽  
Author(s):  
R. Ranganathan ◽  
S. Rakheja ◽  
S. Sankar
Keyword(s):  
Cross Sections ◽  
Optimal Order ◽  
Fluid Structure Interactions ◽  
Plane Model ◽  
Articulated Vehicle ◽  
Turning Response ◽  
The Stability ◽  
Fill Level ◽  
Tank Geometry ◽  
Tank Vehicles

Steady turning model of a partially filled tank vehicle is developed by integrating the roll plane model of the partially filled arbitrarily shaped tank with the static roll plane model of an articulated vehicle. The rollover immunity of the tank vehicle is investigated through computer simulation. The motion of the free surface of liquid and the associated load shift encountered during steady turning are computed using an iterative algorithm. The influence of tank geometry and liquid fill level on the rollover immunity of the tank vehicles is presented. Rollover threshold levels of a tractor-semitrailer vehicle with tanks of circular, modified square and modified oval cross sections are investigated for various fill levels. The influence of compartmenting of the tank on the steady turning response of the vehicle is presented and an optimal order of unloading the various compartments is determined. The study concludes that load shift encountered during steady turning has an adverse effect on the overturning limits of the articulated liquid tank vehicles. The stability of such tank vehicles may be further affected by the dynamic fluid-structure interactions, vehicle transients and driver’s reaction.

Tank Shape Optimization for Enhancement of Roll Stability of Partially Filled Tank Vehicles in Steady Turning

2000 ◽  
Author(s):  
X. Kang ◽  
S. Rakheja ◽  
I. Stiharu ◽  
A. K. W. Ahmed
Keyword(s):  
Cross Sections ◽  
Lateral Acceleration ◽  
Plane Model ◽  
Cross Sectional ◽  
Performance Potentials ◽  
Liquid Load ◽  
Fill Volume ◽  
Total Capacity ◽  
Tank Geometry ◽  
Tank Vehicles

Abstract A generic tank cross-section is proposed to describe the geometry of road tanks used in transportation of bulk liquids, and to explore optimal tank geometry for enhancement of roll stability limits of partially-filled tank vehicles. Two different constrained optimization functions are formulated to minimize the lateral load shift with prescribed cross-sectional c.g. height, and the liquid load shift and c.g. height simultaneously, subject to constraints imposed on the total capacity, overall width and height, and perimeter. Two optimal tank cross-sections are proposed to achieve minimal overturning moments corresponding to medium and high fill ranges. A static roll plane model of the partially-filled generic tank is developed to study the performance potentials of the optimal tanks in terms of translation of the cargo c.g. within the tanks under various fill volumes and vehicle lateral acceleration, which are then compared with those of the conventional circular and modified-oval cross-sectional tanks. The performance potentials of the proposed optimal tanks are further explored in terms of rollover threshold lateral acceleration limit of a partially-filled articulated tank vehicle combination as a function of the fill volume, using a static roll model of the tank vehicle realized by integration of the steady-state roll plane model of the partially-filled generic tank with that of the vehicle. The results reveal that the magnitude of rollover threshold of the 40–70% filled vehicle with the proposed optimal tank geometry is approximately 10% higher than that with a circular cross-sectional tank, and 13–25% higher than that with a modified-oval tank.

Rollover Threshold of Partially Filled Tank Vehicles with Arbitrary Tank Geometry

1993 ◽  
Vol 207 (3) ◽  
pp. 241-244 ◽  
Author(s):  
R Ranganathan
Keyword(s):  
Free Surface ◽  
Closed Form ◽  
Static Analysis ◽  
Cross Sections ◽  
Numerical Technique ◽  
Liquid Load ◽  
Overturning Moment ◽  
Fill Level ◽  
Tank Geometry ◽  
Tank Vehicles

Rollover threshold limits of partially filled tank vehicles equipped with tanks of arbitrary cross-sections are estimated using a simple methodology. Overturning moment caused by the lateral liquid shift within a partially filled arbitrary tank geometry is obtained as a function of the tank shape, fill level and the gradient of the free surface of liquid. The liquid load shift computed using a set of closed-form equations, developed based on the tank shape and fill level, is compared to those obtained from a comprehensive software developed based on a numerical technique. The static rollover threshold of the tank vehicles with arbitrary tank shapes are estimated by balancing the total overturning moment against the restoring moment. The results are compared to those obtained from a kineto-static analysis of tank vehicles.

An Analysis of Dissociation of Molecules in a High Resolution Electron Microscope

1973 ◽  
Vol 31 ◽  
pp. 486-487
Author(s):  
Mihir Parikh
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Cross Sections ◽  
Resolving Power ◽  
Peak Intensity ◽  
Molecular Film ◽  
Resolution Electron ◽  
Dissociation Cross Section ◽  
High Resolution Electron Microscope ◽  
The Stability

It is well known that the resolution of bio-molecules in a high resolution electron microscope depends not just on the physical resolving power of the instrument, but also on the stability of these molecules under the electron beam. Experimentally, the damage to the bio-molecules is commo ly monitored by the decrease in the intensity of the diffraction pattern, or more quantitatively by the decrease in the peaks of an energy loss spectrum. In the latter case the exposure, EC, to decrease the peak intensity from IO to I’O can be related to the molecular dissociation cross-section, σD, by EC = ℓn(IO /I’O) /ℓD. Qu ntitative data on damage cross-sections are just being reported, However, the microscopist needs to know the explicit dependence of damage on: (1) the molecular properties, (2) the density and characteristics of the molecular film and that of the support film, if any, (3) the temperature of the molecular film and (4) certain characteristics of the electron microscope used

TO THE STABILITY OF TANK VEHICLES IN THE BRAKE MODE

2019 ◽  
pp. 27-32
Author(s):  
Denys Popelysh ◽  
Yurii Seluk ◽  
Sergyi Tomchuk
Keyword(s):  
Mathematical Model ◽  
Control Systems ◽  
Distribution Systems ◽  
Traffic Accidents ◽  
Road Traffic ◽  
Center Of Mass ◽  
Dynamic Processes ◽  
Course Stability ◽  
The Stability ◽  
Tank Vehicles

This article discusses the question of the possibility of improving the roll stability of partially filled tank vehicles while braking. We consider the dangers associated with partially filled tank vehicles. We give examples of the severe consequences of road traffic accidents that have occurred with tank vehicles carrying dangerous goods. We conducted an analysis of the dynamic processes of fluid flow in the tank and their influence on the basic parameters of the stability of vehicle. When transporting a partially filled tank due to the comparability of the mass of the empty tank with the mass of the fluid being transported, the dynamic qualities of the vehicle change so that they differ significantly from the dynamic characteristics of other vehicles. Due to large displacements of the center of mass of cargo in the tank there are additional loads that act vehicle and significantly reduce the course stability and the drivability. We consider the dynamics of liquid sloshing in moving containers, and give examples of building a mechanical model of an oscillating fluid in a tank and a mathematical model of a vehicle with a tank. We also considered the method of improving the vehicle’s stability, which is based on the prediction of the moment of action and the nature of the dynamic processes of liquid cargo and the implementation of preventive actions by executive mechanisms. Modern automated control systems (anti-lock brake system, anti-slip control systems, stabilization systems, braking forces distribution systems, floor level systems, etc.) use a certain list of elements for collecting necessary parameters and actuators for their work. This gives the ability to influence the course stability properties without interfering with the design of the vehicle only by making changes to the software of these systems. Keywords: tank vehicle, roll stability, mathematical model, vehicle control systems.

An adaptive sliding mode controller for the lateral control of articulated long vehicles

2018 ◽  
Vol 233 (3) ◽  
pp. 487-515 ◽  
Author(s):  
Naser Esmaeili ◽  
Reza Kazemi ◽  
S Hamed Tabatabaei Oreh
Keyword(s):  
High Speed ◽  
Sliding Mode ◽  
Sliding Mode Controller ◽  
Lane Change ◽  
Lateral Velocity ◽  
Low Speed ◽  
Adaptive Sliding Mode ◽  
Adaptive Sliding Mode Controller ◽  
Articulated Vehicle ◽  
The Stability

Today, use of articulated long vehicles is surging. The advantages of using large articulated vehicles are that fewer drivers are used and fuel consumption decreases significantly. The major problem of these vehicles is inappropriate lateral performance at high speed. The articulated long vehicle discussed in this article consists of tractor and two semi-trailer units that widely used to carry goods. The main purpose of this article is to design an adaptive sliding mode controller that is resistant to changing the load of trailers and measuring the noise of the sensors. Control variables are considered as yaw rate and lateral velocity of tractor and also first and second articulation angles. These four variables are regulated by steering the axles of the articulated vehicle. In this article after developing and verifying the dynamic model, a new adaptive sliding mode controller is designed on the basis of a nonlinear model. This new adaptive sliding mode controller steers the axles of the tractor and trailers through estimation of mass and moment of inertia of the trailers to maintain the stability of the vehicle. An articulated vehicle has been exposed to a lane change maneuver based on the trailer load in three different modes (low, medium and high load) and on a dry and wet road. Simulation results demonstrate the efficiency of this controller to maintain the stability of this articulated vehicle in a low-speed steep steer and high-speed lane change maneuvers. Finally, the robustness of this controller has been shown in the presence of measurement noise of the sensors. In fact, the main innovation of this article is in the designing of an adaptive sliding mode controller, which by changing the load of the trailers, in high-speed and low-speed maneuvers and in dry and wet roads, has the best performance compared to conventional sliding mode and linear controllers.

scholarly journals Global predictions for astrophysics applications

2020 ◽  
Vol 13 ◽  
pp. 18
Author(s):  
P. Demetriou
Keyword(s):  
Nuclear Reaction ◽  
Cross Sections ◽  
Nuclear Reactions ◽  
Nuclear Astrophysics ◽  
Reaction Network ◽  
Reaction Rates ◽  
Reaction Cross ◽  
Hartree Fock ◽  
Microscopic Models ◽  
The Stability

Nuclear reaction rates play a crucial role in nuclear astrophysics. In the last decades there has been an enormous effort to measure reaction cross sections and extensive experimental databases have been compiled as a result. In spite of these efforts, most nuclear reaction network calculations still have to rely on theoretical predic- tions of experimentally unknown rates. In particular, in astrophysics applications such as the s-, r- and p-process nucleosynthesis involving a large number of nuclei and nuclear reactions (thousands). Moreover, most of the ingredients of the cal- culations of reaction rates have to be extrapolated to energy and/or mass regions that cannot be explored experimentally. For this reason it is important to develop global microscopic or semi-microscopic models of nuclear properties that give an accurate description of existing data and are reliable for predictions far away from the stability line. The need for more microscopic input parameters has led to new devel- opments within the Hartree-Fock-Bogoliubov method, some of which are presented in this paper.

Stability of Earth Masses and Slopes

2015 ◽  
pp. 528-588
Keyword(s):  
Cross Sections ◽  
Limit Equilibrium ◽  
Circle Method ◽  
Earth Dam ◽  
Stability Of Slopes ◽  
Solution Of Equations ◽  
Analysis Of Stability ◽  
The Stability ◽  
Cut Slopes ◽  
Type Of Failure

The design of open-cut slopes and embankments, foundations, levees, and earth-dam cross-sections is based primarily on stability considerations. There are many causes and types of earth instability. There are also many ways of analyzing the stability of slopes. The chapter considers the limit equilibrium approach, which aims essentially to determine a factor of safety, F, that would ensure a slope does not fail. The chapter considers the analysis of stability of infinite slopes based on translational type of failure and the analysis of finite slopes using the Swedish Method, Method of Slices, Bishop Simplified Method, Friction Circle Method, and the Translational Method. The solution of equations developed for the analysis of stability of slopes can be tedious and time consuming. A way of reducing the amount of calculation required in slope stability studies is by use of charts based on geometric similarity. The chapter discusses how Taylor (1948) and Janbu (1964) charts are used in stability analysis of slopes. Finally, the chapter discusses ways to reduce the risk of instability in slopes.

Analysis of Antimony-Tin-Based Skutterudites

1998 ◽  
Vol 545 ◽  
Author(s):  
S. B. Schujman ◽  
G. A. Slack ◽  
H. C. Nguyen ◽  
G. S. Nolas ◽  
R. A. Young ◽  
...  
Keyword(s):  
Cross Sections ◽  
Mixed Valence ◽  
Partial Replacement ◽  
X Ray Diffraction ◽  
Extra Charge ◽  
Semiconducting Properties ◽  
Wide Range ◽  
Diffraction Patterns ◽  
The Stability ◽  
Unit Cell Constant

AbstractSince the proposal of skutterudites as possible Phonon-Glass, Electron-Crystal materials, a lot of work has been done trying to fill the structural voids with foreign “rattling” atoms. In order to keep the electronic count per unit cell constant (and thus, the semiconducting properties of most of the compounds under study) partial replacement of either the cation or the anion in the original formula by an appropriate neighbor in the periodic table is an option. In the case of antimonides, replacing part of the Sb with Ge or Sn in order to compensate the extra charge introduced by void fillers has proved useful for compounds based on rare-earth filled IrSb3. In the case of RhSb3, we found that large quantities of Sn can be incorporated into the skutterudite structure of RhSb3 without either filling the voids or producing charge carriers.We have analyzed the stability of several cross-sections of the Rh-Sb-Sn ternary system and have found a wide range of compositions with the basic skutterudite structure as we vary the Sn content. In all the cases, the tin goes substitutionally into the antimony sites. The voids remain empty. Density measurements suggest the existence of metal vacancies, confirmed by Rietveld refinement of the powder X-ray diffraction patterns. The possibility of Sn-induced mixed-valence of Rh on the anion sites is being investigated.

MHD Stability for a Class of Tokamak Equilibria with Fixed Boundaries

1978 ◽  
Vol 33 (7) ◽  
pp. 792-798
Author(s):  
W. Kerner
Keyword(s):  
Stability Analysis ◽  
Normal Mode ◽  
Cross Sections ◽  
Stability Limit ◽  
Stability Behavior ◽  
Mhd Stability ◽  
The Stability ◽  
High Beta ◽  
Fixed Boundaries ◽  
Flat Current

The stability behavior with respect to internal modes is discussed for a class of tokamak equilibria with non-circular cross-sections and essentially flat current profiles. The stability analysis is done by computer both symbolically and numerically with the help of a normal mode code, which extremizes the Lagrangian of the system . It is found that the stability limit agrees well with that of the Mercier criterion. There are stable high-beta equilibria in this model.

The Stability Analysis of Reinforced Earth Retaining Wall System and the Study of its Reinforcement Optimization

2011 ◽  
Vol 90-93 ◽  
pp. 2389-2392
Author(s):  
Hai Yan Ju ◽  
Gui Qing Gao ◽  
Jian Hua Li ◽  
Jiang Qian Zhao ◽  
Zhang Ming Li
Keyword(s):  
Cross Sections ◽  
Design Method ◽  
Retaining Wall ◽  
Physical Behavior ◽  
Reinforced Earth ◽  
Slope Treatment ◽  
The Stability ◽  
Relationship Of ◽  
The Relationship ◽  
System Program

Because the relationship is not considered between physical behavior and cross sections of bars, the conventional reinforced earth retaining wall design based on constant value would lead to some limitations: the haul-resistant coefficient of the top wall is not enough, but it goes beyond at the bottom of retaining wall. In the paper, considering the SARMA method, based on computing formula of traditional slope stability, the detailed programme is realized by the language of FORTRAN, it can make up deficiency that lies in the tradition reinforced earth retaining wall by considering the relationship of physical behavior and cross sections, lengths and layers of bars. Finally, the system program has been applied to a slope treatment project in Guangzhou. Compared with the design method of traditional regulations, it is demonstrated that the optimum length required is obtained, the cross section and length of bars are fully used, and the design is simplified.

Sign in / Sign up

Export Citation Format

Share Document