scholarly journals Modified Lateral Pressure Formula of Shallow and Circular Silo Considering the Elasticities of Silo Wall and Storage Materials

2021 ◽  
Author(s):  
Zhijun Xu ◽  
Pengfei Liang
Keyword(s):  
Relative Error ◽  
Lateral Pressure ◽  
Dynamic Pressure ◽  
Earth Pressure ◽  
Storage Materials ◽  
Modified Method ◽  
Safety Design ◽  
Pressure Calculation ◽  
And Storage ◽  
Good Agreement

Abstract For the shallow and circular silo(SCS), when the aspect ratio is between 1.0 and 1.5, the lateral pressure especially dynamic pressure may cause destruction if the size of the silo is large. In general, the lateral pressures should be calculated simultaneously according to the shallow silo and the deep silo calculation formulas based on Rankine’s earth pressure theory and Janssen’s theory, respectively, and the larger value of them should be adopted. However, whether the two formulas are reasonable needs to be verified. This paper proposed a modified calculation method of lateral pressure on the silo wall of SCS, considering the elasticities of silo wall and storage materials. The availability of shallow silo and deep silo methods, and the modified method were compared with the experiment and simulation. The results show that the Rankine’s formula is too conservative for the static lateral pressure, and the results of the modified method and Janssen formula are close to that of the experimental and simulation. For the dynamic lateral pressure calculation, Rankine theory is unsafe for the discharging load. The relative error of the dynamic lateral pressure based on Janssen theory is between 20% and 30%, which is too large. The dynamic lateral pressure calculated by the modified method is in good agreement with that of the experimental and simulation, and the relative error is less than 10%. Therefore, the modified method of lateral pressure formula is reasonable, which can provide guidance for the safety design of silo structure.

Simulation for Silos Discharge with 2D DEM

2011 ◽  
Vol 236-238 ◽  
pp. 2721-2724
Author(s):  
Shou Yi Bi ◽  
Xing Pei Liang
Keyword(s):  
Numerical Model ◽  
Discrete Element Method ◽  
Static Pressure ◽  
Lateral Pressure ◽  
Dynamic Pressure ◽  
Discrete Element ◽  
Particle Flow ◽  
Static Equilibrium State ◽  
Good Agreement ◽  
Element Method

In this paper, using the discrete element method (PFC2D)particle flow procedure to establish a model of cylindrical silo, in the warehouse filled with particles within the reach of static equilibrium state, then the record of its wall static lateral pressure measurement value, while monitoring the measured dynamic wall pressure during the silo discharging. It was shown that the static pressure as well as the dynamic pressure simulated with the numerical model is in good agreement with the experimental results. So the discrete element method can give a new way to study dynamic question of silos.

Study on Silo Pressure by Consider Storage Materials Density Changed along the Height

2012 ◽  
Vol 517 ◽  
pp. 797-800
Author(s):  
Zhi Yong Yang ◽  
Shun Hu Liu ◽  
Song Zhao ◽  
Jun Hu ◽  
Zeng Chan Lu
Keyword(s):  
Differential Equation ◽  
Density Stratification ◽  
Maximum Pressure ◽  
Actual Case ◽  
Storage Materials ◽  
Pressure Calculation ◽  
The Difference

The difference existed between results of silos pressure calculation and the actual case, because the influence of density stratification was not taken into consideration. The aim of this paper was to obtain silo pressure calculating formula by consider of storage materials density stratified. To this end, we assume that the density was continuous changed along the height and differential equation of the storage materials pressure was established. By compared the results calculated from the equation with the results calculated from the code, it is found that the maximum pressure increased. The results showed density stratified is an import factor for silo pressure calculation and the equation obtained in this paper can provide references for the theory of silo pressure calculation.

The penetration and ricochet of ogive-nosed rigid projectiles obliquely impacting metallic targets

2021 ◽  
pp. 204141962110377
Author(s):  
Yaniv Vayig ◽  
Zvi Rosenberg
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
Dynamic Pressure ◽  
Oblique Impacts ◽  
Simulation Results ◽  
The Impact ◽  
Penetration Depths ◽  
Resistance To Penetration ◽  
Good Agreement

A large number of 3D numerical simulations were performed in order to follow the trajectory changes of rigid CRH3 ogive-nosed projectiles, impacting semi-infinite metallic targets at various obliquities. These trajectory changes are shown to be related to the threshold ricochet angles of the projectile/target pairs. These threshold angles are the impact obliquities where the projectiles end up moving in a path parallel to the target’s face. They were found to depend on a non-dimensional entity which is equal to the ratio between the target’s resistance to penetration and the dynamic pressure exerted by the projectile upon impact. Good agreement was obtained by comparing simulation results for these trajectory changes with experimental data from several published works. In addition, numerically-based relations were derived for the penetration depths of these ogive-nosed projectiles at oblique impacts, which are shown to agree with the simulation results.

Aerodynamic Similarity Principles and Scaling Laws for Windmilling Fans

2018 ◽  
Author(s):  
Dilip Prasad
Keyword(s):  
Rotational Speed ◽  
Pressure Loss ◽  
Scaling Laws ◽  
Dynamic Pressure ◽  
Stagnation Pressure ◽  
Design Parameters ◽  
Similarity Parameter ◽  
Wide Range ◽  
Simulation Results ◽  
Good Agreement

Windmilling requirements for aircraft engines often define propulsion and airframe design parameters. The present study is focused is on two key quantities of interest during windmill operation: fan rotational speed and stage losses. A model for the rotor exit flow is developed, that serves to bring out a similarity parameter for the fan rotational speed. Furthermore, the model shows that the spanwise flow profiles are independent of the throughflow, being determined solely by the configuration geometry. Interrogation of previous numerical simulations verifies the self-similar nature of the flow. The analysis also demonstrates that the vane inlet dynamic pressure is the appropriate scale for the stagnation pressure loss across the rotor and splitter. Examination of the simulation results for the stator reveals that the flow blockage resulting from the severely negative incidence that occurs at windmill remains constant across a wide range of mass flow rates. For a given throughflow rate, the velocity scale is then shown to be that associated with the unblocked vane exit area, leading naturally to the definition of a dynamic pressure scale for the stator stagnation pressure loss. The proposed scaling procedures for the component losses are applied to the flow configuration of Prasad and Lord (2010). Comparison of simulation results for the rotor-splitter and stator losses determined using these procedures indicates very good agreement. Analogous to the loss scaling, a procedure based on the fan speed similarity parameter is developed to determine the windmill rotational speed and is also found to be in good agreement with engine data. Thus, despite their simplicity, the methods developed here possess sufficient fidelity to be employed in design prediction models for aircraft propulsion systems.

Aerodynamic Similarity Principles and Scaling Laws for Windmilling Fans

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Dilip Prasad
Keyword(s):  
Rotational Speed ◽  
Pressure Loss ◽  
Scaling Laws ◽  
Dynamic Pressure ◽  
Stagnation Pressure ◽  
Design Parameters ◽  
Similarity Parameter ◽  
Wide Range ◽  
Simulation Results ◽  
Good Agreement

Windmilling requirements for aircraft engines often define propulsion and airframe design parameters. The present study is focused on two key quantities of interest during windmill operation: fan rotational speed and stage losses. A model for the rotor exit flow is developed that serves to bring out a similarity parameter for the fan rotational speed. Furthermore, the model shows that the spanwise flow profiles are independent of the throughflow, being determined solely by the configuration geometry. Interrogation of previous numerical simulations verifies the self-similar nature of the flow. The analysis also demonstrates that the vane inlet dynamic pressure is the appropriate scale for the stagnation pressure loss across the rotor and splitter. Examination of the simulation results for the stator reveals that the flow blockage resulting from the severely negative incidence that occurs at windmill remains constant across a wide range of mass flow rates. For a given throughflow rate, the velocity scale is then shown to be that associated with the unblocked vane exit area, leading naturally to the definition of a dynamic pressure scale for the stator stagnation pressure loss. The proposed scaling procedures for the component losses are applied to the flow configuration of Prasad and Lord (2010). Comparison of simulation results for the rotor-splitter and stator losses determined using these procedures indicates very good agreement. Analogous to the loss scaling, a procedure based on the fan speed similarity parameter is developed to determine the windmill rotational speed and is also found to be in good agreement with engine data. Thus, despite their simplicity, the methods developed here possess sufficient fidelity to be employed in design prediction models for aircraft propulsion systems.

Modeling the Effect of Water Activity, pH, and Temperature on the Probability of Enterotoxin A Production by Staphylococcus aureus

2016 ◽  
Vol 79 (1) ◽  
pp. 148-152 ◽  
Author(s):  
TIAN DING ◽  
YAN-YAN YU ◽  
CHENG-AN HWANG ◽  
QING-LI DONG ◽  
SHI-GUO CHEN ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Water Activity ◽  
Storage Temperature ◽  
Probability Model ◽  
Toxin Production ◽  
Factors Affecting ◽  
Model Predictions ◽  
And Storage ◽  
Storage Temperatures ◽  
Good Agreement

ABSTRACT The objectives of this study were to develop a probability model of Staphylococcus aureus enterotoxin A (SEA) production as affected by water activity (aw), pH, and temperature in broth and assess its applicability for milk. The probability of SEA production was assessed in tryptic soy broth using 24 combinations of aw (0.86 to 0.99), pH (5.0 to 7.0), and storage temperature (10 to 30°C). The observed probabilities were fitted with a logistic regression to develop a probability model. The model had a concordant value of 97.5% and concordant index of 0.98, indicating that the model satisfactorily describes the probability of SEA production. The model showed that aw, pH, and temperature were significant factors affecting the probability of toxin production. The model predictions were in good agreement with the observed values obtained from milk. The model may help manufacturers in selecting product pH and aw and storage temperatures to prevent SEA production.

Design of Laterally Loaded Plating—Uniform Pressure Loads

1981 ◽  
Vol 25 (02) ◽  
pp. 77-89
Author(s):  
Owen F. Hughes
Keyword(s):  
High Speed ◽  
Lateral Pressure ◽  
Experimental Studies ◽  
Steel Plates ◽  
Subsequent Paper ◽  
Rigid Plastic ◽  
Welded Steel ◽  
High Speed Impact ◽  
Laterally Loaded ◽  
Good Agreement

An explicit formula is presented for the design of welded steel plates subjected to uniform lateral pressure, on the basis of a designer-specified level of acceptable permanent set, including that due to welding. The formula is derived from a combination of theoretical and experimental studies and shows good agreement with experimental results. For the convenience of designers the formula is also given in the form of design curves. The paper also delineates the areas of application of this and other formulas for laterally loaded plating. In brief, the paper shows that for static and quasistatic loads the formula derived herein is more accurate than formulas based on either the pseudo-elastic or the rigid-plastic approach. As the load becomes more dynamic the rigid-plastic approach becomes more appropriate, and for high-speed impact loads the rigid-plastic approach is best. For quasistatic loads, such as slamming, the formula presented herein is somewhat conservative while the rigid-plastic formulas are somewhat optimistic. A similar formula for concentrated loads (such as wheel loads) will be presented in a subsequent paper.

Transition-metal-based layered double hydroxides tailored for energy conversion and storage

2018 ◽  
Vol 6 (1) ◽  
pp. 12-29 ◽  
Author(s):  
Rajkumar Patel ◽  
Jung Tae Park ◽  
Madhumita Patel ◽  
Jatis Kumar Dash ◽  
E. Bhoje Gowd ◽  
...  
Keyword(s):  
Energy Storage ◽  
Transition Metal ◽  
Energy Conversion ◽  
Surface Area ◽  
Layered Double Hydroxides ◽  
Energy Storage Materials ◽  
Storage Materials ◽  
Energy Conversion And Storage ◽  
Double Hydroxides ◽  
And Storage

Transition metal based layered double hydroxides are important energy storage materials. The overall performances of the electrodes are dependent on conductivity, crystallinity, morphology, and surface area.

Study on Soil Pressure of High Fill Retaining Wall in Construction Stage

2012 ◽  
Vol 204-208 ◽  
pp. 718-721 ◽  
Author(s):  
Peng Li ◽  
Xiao Song
Keyword(s):  
Retaining Wall ◽  
Earth Pressure ◽  
Monitoring Data ◽  
Experiment Study ◽  
Pressure Monitoring ◽  
Soil Pressure ◽  
Construction Stage ◽  
The Earth ◽  
Pressure Calculation ◽  
Practical Guidance

The traditional formula using for the calculation of Expressway on high embankment of the retaining wall and the earth pressure can not be very good practical. In order to accurately determine the soil pressure calculation of the complex retaining wall in construction stage for guaranteeing the engineering safety, the experiment study on soil pressure is done, and the study on soil pressure monitoring data is also done. Then the valuable conclusions are obtained to facilitate better practical guidance for construction.

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