Free Fall Stability and Base Pressure Drop Tests for Planetary Entry Configurations

1971 ◽  
Vol 8 (7) ◽  
pp. 790-793 ◽  
Author(s):  
J. M. CASSANTO ◽  
P. BUCE
Keyword(s):  
Pressure Drop ◽  
Free Fall ◽  
Base Pressure ◽  
Drop Tests ◽  
Planetary Entry

scholarly journals Numerical Model Study of Prototype Drop Tests on Cube and Cubipod® Concrete Armor Units Using the Combined Finite–Discrete Element Method

2021 ◽  
Vol 9 (5) ◽  
pp. 460
Author(s):  
Giulio Scaravaglione ◽  
John-Paul Latham ◽  
Jiansheng Xiang
Keyword(s):  
Discrete Element Method ◽  
Validation Study ◽  
Free Fall ◽  
Discrete Element ◽  
Drop Test ◽  
Modeling Methodology ◽  
Model Study ◽  
Drop Tests ◽  
Rubble Mound Breakwaters ◽  
Element Method

This paper aims to evaluate the structural strength of unreinforced concrete armor units (CAU), named Cubipod®, used on rubble-mound breakwaters and coastal structures, through a numerical methodology using the combined finite–discrete element method (FDEM). A numerical modeling methodology is developed to reproduce the results of an experimental examination published by Medina et al. (2011) of a free-fall drop test performed on a 15 t conventional Cubic block and a 16 t Cubipod® unit. The field results of the Cube drop tests were used to calibrate the model. The numerically simulated response to the Cubipod® test is then discussed in the context of a validation study. The calibration process and validation study provide insights into the sensitivity of breakage to tensile strength and collision angle, as well as a better understanding of the crushing and cracking damage of this unit under drop test impact conditions.

scholarly journals Performance analysis of the protective effects of bicycle helmets during impact and crush tests in pediatric skull models

2012 ◽  
Vol 10 (6) ◽  
pp. 490-497 ◽  
Author(s):  
Tobias A. Mattei ◽  
Brandon J. Bond ◽  
Carlos R. Goulart ◽  
Chris A. Sloffer ◽  
Martin J. Morris ◽  
...  
Keyword(s):  
Impact Force ◽  
Compressive Force ◽  
Free Fall ◽  
Protective Effects ◽  
Human Cadaver ◽  
Bicycle Helmet ◽  
Bicycle Helmets ◽  
Drop Tests ◽  
Flat Steel ◽  
Human Skulls

Object Bicycle accidents are a very important cause of clinically important traumatic brain injury (TBI) in children. One factor that has been shown to mitigate the severity of lesions associated with TBI in such scenarios is the proper use of a helmet. The object of this study was to test and evaluate the protection afforded by a children's bicycle helmet to human cadaver skulls with a child's anthropometry in both “impact” and “crushing” situations. Methods The authors tested human skulls with and without bicycle helmets in drop tests in a monorail-guided free-fall impact apparatus from heights of 6 to 48 in onto a flat steel anvil. Unhelmeted skulls were dropped at 6 in, with progressive height increases until failure (fracture). The maximum resultant acceleration rates experienced by helmeted and unhelmeted skulls on impact were recorded by an accelerometer attached to the skulls. In addition, compressive forces were applied to both helmeted and unhelmeted skulls in progressive amounts. The tolerance in each circumstance was recorded and compared between the two groups. Results Helmets conferred up to an 87% reduction in so-called mean maximum resultant acceleration over unhelmeted skulls. In compression testing, helmeted skulls were unable to be crushed in the compression fixture up to 470 pound-force (approximately 230 kgf), whereas both skull and helmet alone failed in testing. Conclusions Children's bicycle helmets provide measurable protection in terms of attenuating the acceleration experienced by a skull on the introduction of an impact force. Moreover, such helmets have the durability to mitigate the effects of a more rare but catastrophic direct compressive force. Therefore, the use of bicycle helmets is an important preventive tool to reduce the incidence of severe associated TBI in children as well as to minimize the morbidity of its neurological consequences.

scholarly journals Numerical Modelling of the Three-Dimensional Slamming Problem

2002 ◽  
Author(s):  
Matthieu Tourbier ◽  
Bernard Peseux ◽  
Bundi Donguy ◽  
Laurent Gornet
Keyword(s):  
Finite Element Method ◽  
Experimental Investigation ◽  
Thickness Distribution ◽  
Three Dimensional ◽  
Free Fall ◽  
The Finite Element Method ◽  
Hydrodynamic Problem ◽  
In Series ◽  
Drop Tests ◽  
Good Agreement

This paper deals with the slamming phenomenon for deformable structures. In a first part, a three-dimensional hydrodynamic problem is solved numerically with the Finite Element Method. The results for a rigid body are successfully compared to the analytical solutions. After the numerical analysis, an experimental investigation is presented. It consists in series of free fall drop-tests of rigid, deformable cones shaped models with different deadrise angle and thickness. Distribution of the pressure and its evolution are analyzed. Numerical and experimental results are compared and present good agreement.

Single Phase Pressure-Drop Tests in 7-Element Bundles With Different Endplug Shapes

2008 ◽  
Author(s):  
S. K. Yang
Keyword(s):  
Pressure Drop ◽  
Single Phase ◽  
Flat Surface ◽  
Reactor Core ◽  
Drop Tests ◽  
Round Surface ◽  
The Difference ◽  
Phase Pressure

Pressure-drop characteristics in CANDU® fuel bundles are of importance for critical power analysis and safety trip analysis for the reactor core. Different kinds of endplug shapes are being used in different fuel designs. The difference in endplug shape may result in slightly different hydraulic characteristics of the fuel bundles. Single-phase pressure-drop tests were performed in aligned and misaligned (15° and 30°) 7-element bundle strings with three different endplug shapes (Type 1, 2 and 3): Type 1 and 3 with round surface, and Type 2 with flat surface. The test results showed that the bundle-loss coefficients of the misaligned bundle with Type 2 having flat surface presented the highest value among the three-endplug types: 8.6% higher on average, compared to those of the misaligned bundle with Type 1 endplugs (Type 1 as a reference).

Sign in / Sign up

Export Citation Format

Share Document