STATISTICAL ANALYSIS OF BLAST WAVE DECAY COEFFICIENT AND MAXIMUM PRESSURE BASED ON EXPERIMENTAL RESULTS

2020 ◽  
Author(s):  
SANJA LUKIĆ ◽  
HRVOJE DRAGANIĆ ◽  
GORAN GAZIĆ ◽  
IVAN RADIĆ
Keyword(s):  
Statistical Analysis ◽  
Blast Wave ◽  
Experimental Results ◽  
Maximum Pressure ◽  
Decay Coefficient ◽  
Wave Decay

scholarly journals Analysis of the blast wave decay coefficient using the Kingery–Bulmash data

2016 ◽  
Vol 7 (3) ◽  
pp. 409-429 ◽  
Author(s):  
Vasilis Karlos ◽  
George Solomos ◽  
Martin Larcher
Keyword(s):  
Blast Wave ◽  
Decay Coefficient ◽  
Wave Decay

scholarly journals Experimental Investigation of a Novel Blast Wave Mitigation Device

2006 ◽  
Author(s):  
Zhenbi Su ◽  
Zhaoyan Zhang ◽  
George Gogos ◽  
Reed Skaggs ◽  
Bryan Cheeseman ◽  
...  
Keyword(s):  
Shock Wave ◽  
Experimental Investigation ◽  
Wave Propagation ◽  
Blast Wave ◽  
Hopkinson Bar ◽  
Honeycomb Structure ◽  
Experimental Results ◽  
Maximum Pressure ◽  
Propagation Process ◽  
Piston Cylinder

A novel blast wave mitigation device was investigated experimentally in this paper. The device consists of a piston-cylinder assembly. A shock wave is induced within the cylinder when a blast wave impacts on the piston. The shock wave propagates inside the device and is reflected repeatedly. The shock wave propagation process inside the device lengthens the duration of the force on the base of the device to several orders of magnitude of the duration of the blast wave, while it decreases the maximum pressure by several orders of magnitude. Two types of experiments were carried out to study the blast wave mitigation device. The first type of experiments was done with honeycomb structures protected by the blast wave mitigation device. Experimental results show that the device can adequately protect the honeycomb structure. A second type of experiments was done using a Hopkinson bar to measure the pressure transmitted through the blast wave mitigation device. The experimental results agree well with results from a theoretical model.

scholarly journals Optimum Drafting Conditions Of Polyester And Viscose Blend Yarns

2017 ◽  
Vol 17 (3) ◽  
pp. 213-218
Author(s):  
Mohammad Hatamvand ◽  
Seyed Abbas Mirjalili ◽  
Saeid Fattahi ◽  
Tariq Bashir ◽  
Mikael Skrifvars
Keyword(s):  
Statistical Analysis ◽  
Experimental Design ◽  
Experimental Results ◽  
Maximum Pressure ◽  
Ring Spinning ◽  
High Quality ◽  
Blend Ratio ◽  
Yarn Quality ◽  
Yarn Structure ◽  
Proper Orientation

AbstractIn this study, we used an experimental design to investigate the influence of the total draft, break draft, distance between the aprons (Clips) and production roller pressure on yarn quality in order to obtain optimum drafting conditions for polyester and viscose (PES/CV) blend yarns in ring spinning frame. We used PES fibers (1.4 dtex × 38 mm long) and CV fibers (1.6 dtex × 38 mm long) to spin a 20 Tex blend yarn of PES (70%)/CV (30%) blend ratio. When the break draft, adjustment of distance between of aprons and roller pressure is not reasonable, controlling and leading of the fibers is not sufficient for proper orientation of the fibers in the yarn structure to produce a high quality yarn. Experimental results and statistical analysis show that the best yarn quality will be obtained under drafting conditions total draft of 38, 1.2 break draft, 2.8 mm distance between of aprons and maximum pressure of the production top roller (18daN).

scholarly journals Experimental Investigation of a Novel Blast Wave Mitigation Device

2009 ◽  
Vol 16 (6) ◽  
pp. 543-553 ◽  
Author(s):  
Zhenbi Su ◽  
Wen Peng ◽  
Zhaoyan Zhang ◽  
George Gogos ◽  
Reed Skaggs ◽  
...  
Keyword(s):  
Shock Wave ◽  
Experimental Investigation ◽  
Blast Wave ◽  
Hopkinson Bar ◽  
Honeycomb Structure ◽  
Experimental Results ◽  
Maximum Pressure ◽  
Propagation Process ◽  
Piston Cylinder ◽  
Order Of Magnitude

A novel blast wave mitigation device was investigated experimentally in this paper. The device consists of a piston-cylinder assembly. A shock wave is induced within the cylinder when a blast wave impacts on the piston. The shock wave propagates inside the device and is reflected repeatedly. The shock wave propagation process inside the device lengthens the duration of the force on the base of the device to several orders of magnitude of the duration of the blast wave, while it decreases the maximum pressure over an order of magnitude. Two types of experiments were carried out to study the blast wave mitigation device. The first type of experiments was done with honeycomb structures protected by the blast wave mitigation device. Experimental results show that the device can adequately protect the honeycomb structure. A second type of experiments was done using a Hopkinson bar to measure the pressure transmitted through the blast wave mitigation device. The experimental results agree well with results from a theoretical model.

scholarly journals Wireless distance measurement by means of ultra-wideband chaotic radio pulses

2019 ◽  
Vol 30 ◽  
pp. 12005
Author(s):  
Elena Efremova ◽  
Alexander Dmitriev ◽  
Lev Kuzmin ◽  
Manvel Petrosyan
Keyword(s):  
Statistical Analysis ◽  
Distance Measurement ◽  
Experimental Results ◽  
Ultra Wideband

A method for wireless distance measurement using ultrawideband chaotic radio pulses based on statistical analysis is proposed. Experimental results are discussed.

Calculation of Punch Force and Maximum Pressure for Tube Extrusion

2000 ◽  
Author(s):  
S.-H. Zhang ◽  
Y.-L. Shang
Keyword(s):  
Upper Bound ◽  
Physical Modeling ◽  
Steel Tube ◽  
Experimental Results ◽  
Maximum Pressure ◽  
Punch Force ◽  
Tube Extrusion ◽  
Tooling System ◽  
Very High ◽  
Good Agreement

Abstract Punch force and maximum pressure for tube extrusion can be predicted with an upper bound theory-based program POLSK. Experiments of steel tube extrusion and wax physical modeling were performed. The punch force and the maximum pressure values were obtained. Comparisons were made among the experimental results, physical modeling results and upper bound predictions. It was found that a medium extrusion coefficient causes the lowest pressure on the tooling system, very low and very high extrusion coefficients can both cause very high pressure. It is proved that the upper bound predictions are in good agreement with the experimental results and the upper bound program is suitable for use of steel tube extrusion design.

Roof truss systems under blast loads

2017 ◽  
Author(s):  
◽  
Doaa Bondok
Keyword(s):  
Finite Element ◽  
Blast Wave ◽  
Numerical Models ◽  
Blast Resistance ◽  
Experimental Results ◽  
Blast Loads ◽  
Damage Level ◽  
Dynamic Analyses ◽  
Roof Truss ◽  
Static Resistance

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Designing roof systems for blast loading is quite complex. Many uncertainties still exist in this vital research area. The typical single degree of freedom dynamic modeling approach that is used widely by the blast design community is based on idealization of the structural components. Limited information exists on the blast response of different roof systems and their blast design methodology is lacking. Moreover, the blast roof load is based on approximate methods to produce a blast wave equivalent to the actual propagated wave. This approximation needs to be evaluated to ensure the blast designs are sufficient. The uncertainty of blast loads and roof resistance can lead to either excessive costs or insufficient blast designs. Therefore, the research presented here aims to bridge the gap in the knowledge about the blast resistance of different roof systems; Open Web Steel Joist (OWSJ) systems and Cold-Formed Steel (CFS) roof systems as well as to assess the accuracy of the existing ASCE and UFC approximate roof blast loads. In this dissertation, dynamic analyses using the finite element method were performed on a roof component to compare the dynamic responses resulting from a propagated blast wave and the current equivalent blast load techniques. Blast field data were used to verify the dynamic finite element model. Results have shown that current methodologies should be corrected if used to design for blast loading. Previous experiments were used to verify advanced finite element models developed to predict the complete static resistance of OWSJs including the failure limits. The verified models were used to perform dynamic analyses to predict the system dynamic response under equivalent blast loads. Analyses and energy comparisons at superficial damage level showed that the current methodology, used to calculate OWSJ static resistance, predicted 27% and 88% higher energies than the experimental ones for 16K5 and 26K5 joists, respectively. While at moderate damage levels current methodology predicted 47% and 108% higher energies than the experimental ones for 16K5 and 26K5 joists. Evaluating the blast resistance of CFS roof systems is challenging. There is a lack of existing design guidelines and response criteria for CFS roof systems. The UFC manual provides information that is relevant to CFS panels only. The approach that was adopted in this dissertation started with an extensive testing program of different types of end connections used for CFS roof trusses to investigate their failure capacities in horizontal and vertical directions. Analyses of the experimental results showed that using Hilti PAFs are more favorable than using bolts for supporting CFS truss end-connections as it was indicated in their strength and toughness. Moreover, the experimental results were used to verify the deformable screw behavior and the finite element model developed to predict the progressive failure of the truss end-connections. Small-scale CFS roof truss specimens were tested to failure under quasi-static loading. The static resistance of these systems and the associated failure mechanisms were identified. Experimental results and energy comparisons show that the truss layout and the shape of loading significantly affect the performance of the truss and the failure mechanism. Three-dimensional numerical models were developed and verified against the experimental results. The advanced models predicted the static resistance to failure with a high level of accuracy. Numerical analyses were performed to enhance the static resistance of CFS roof systems for blast analysis. Experimental and numerical analyses have shown that the energy absorbed is improved significantly when the web members susceptible to buckling are strengthened. In addition, the numerical models were used to perform dynamic analyses on a flat CFS roof system subjected to different threat levels. Von Mises stress distributions were used to investigate and determine the damage level corresponding to each threat level. The research presented in this dissertation focused on investigating the equivalent roof blast load as well as the blast resistance of different roof truss systems. The static resistance required for SDOF analysis was evaluated and identified using physical experiments and verified advanced finite element models. Failure capacities of truss end-connections were identified to improve truss system performance against blast. Based on experimental and numerical analyses, recommendations are given to arrive at an enhanced blast resistance. Dynamic analyses on 3D truss numerical models were used to investigate the damage level under certain threats. It is recommended for future work to perform field tests to address the critical differences between the measured field roof wave and the UFC manual roof blast wave. The developed numerical models can be potentially used as an analysis tool to investigate the resistance of other truss profiles and to examine the failure mechanisms that may lead to the development of an analytical model for the static resistance of roof systems. It is recommended for future work to compare the dynamic analyses performed using the developed numerical models and the SDOF dynamic analysis to provide more insight into the idealization of this technique.

On the Application of Statistical Analysis for Interpretation of Experimental Results in Environmental Microbiology

Microbiology ◽  
2019 ◽  
Vol 88 (2) ◽  
pp. 232-239
Author(s):  
A. Yu. Kallistova ◽  
A. F. Sabrekov ◽  
V. M. Goncharov ◽  
N. V. Pimenov ◽  
M. V. Glagolev
Keyword(s):  
Statistical Analysis ◽  
Environmental Microbiology ◽  
Experimental Results

The Strength of Thick-Walled Cylinders

1959 ◽  
Vol 81 (2) ◽  
pp. 95-111 ◽  
Author(s):  
B. Crossland ◽  
S. M. Jorgensen ◽  
J. A. Bones
Keyword(s):  
Shear Stress ◽  
Mild Steel ◽  
Close Agreement ◽  
Large Strain ◽  
Tension Test ◽  
Experimental Results ◽  
Maximum Pressure ◽  
Strain Behavior ◽  
Pressure Tests ◽  
Strain Data

Comprehensive pressure tests have been carried out on thick-walled, closed-ended cylinders made from a mild steel and a hardened and tempered steel, the maximum pressure reached being 94,000 lb/in.2 The complete theoretical behavior of the cylinders is computed from shear stress-strain data obtained from torsion tests and is shown to be in very close agreement with the experimental results. In addition, a method is given for deriving the large strain behavior of the cylinders from tension test data. When compared with the experimental results this approach gives larger errors, the theoretical values of pressure being consistently high. Finally, ultimate pressures have been calculated from two empirical expressions.

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