scholarly journals Dynamic Response of Buried Silo Caused by Underground Explosion

2004 ◽  
Vol 11 (5-6) ◽  
pp. 665-684 ◽  
Author(s):  
Sylwester Kobielak ◽  
Theodor Krauthammer
Keyword(s):  
Dynamic Response ◽  
Experimental Results ◽  
Underground Explosion ◽  
Burial Depth ◽  
Charge Mass ◽  
Different Depths ◽  
Two Sides ◽  
Opposite Line

Experimental results of normal and tangential pressures on a buried silo wall caused by buried charge explosions are presented in the paper. The measured pressures depended on the charge mass, and its burial depth and distance from the silo front. Pressures were measured by sensors attached to the silo wall at different depths along to four diametrically opposite line generators located at the front, rear and two sides. The influence of each parameter is analyzed and discussed.

The Effect of Strain Rate on the Material Characteristics of Nickel-Based Superalloy Inconel 718

2007 ◽  
Vol 340-341 ◽  
pp. 283-288 ◽  
Author(s):  
Jung Han Song ◽  
Hoon Huh
Keyword(s):  
Dynamic Response ◽  
High Strain Rate ◽  
Strain Rate ◽  
Turbine Blade ◽  
Inconel 718 ◽  
High Speed ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Experimental Results ◽  
Stress Wave Propagation

The dynamic response of the turbine blade materials is indispensable for analysis of erosions of turbine blades as a result of impulsive loading associated with gas flow. This paper is concerned with the dynamic material properties of the Inconel 718 alloy which is widely used in the high speed turbine blade. The dynamic response at the corresponding level of the strain rate should be acquired with an adequate experimental technique and apparatus due to the inertia effect and the stress wave propagation. In this paper, the dynamic response of the Inconel 718 at the intermediate strain rate ranged from 1/s to 400/s is obtained from the high speed tensile test and that at the high strain rate above 1000/s is obtained from the split Hopkinson pressure bar test. The effects of the strain rate on the dynamic flow stress, the strain rate sensitivity and the failure elongation are evaluated with the experimental results. Experimental results from both the quasi-static and the high strain rate up to 3000/s are interpolated in order to construct the constitutive relation that should be applied to simulate the dynamic behavior of the turbine blade made of the Inconel 718.

THE INFLUENCE OF COMPOSITION, DIAGENESIS AND COMPACTION ON SEAL CAPACITY IN THE MUDERONG SHALE, CARNARVON BASIN

2004 ◽  
Vol 44 (1) ◽  
pp. 201 ◽  
Author(s):  
G.E. Kovack ◽  
D.N. Dewhurst ◽  
M.D. Raven ◽  
J.G. Kaldi
Keyword(s):  
Effective Stress ◽  
Pore Geometry ◽  
Burial Depth ◽  
Threshold Pressure ◽  
Direct Influence ◽  
Different Depths ◽  
Northern Carnarvon Basin ◽  
Vertical Effective Stress ◽  
Mercury Injection Capillary Pressure ◽  
Carnarvon Basin

The Muderong Shale blankets most of the northern Carnarvon Basin and is the top seal to over 90% of all commercial discoveries. This study examines the influence that vertical effective stress, mineralogy and diagenesis have on regional variations of seal capacity. Throughout the basin, threshold pressures (determined from Mercury Injection Capillary Pressure (MICP) analyses), range from less than 1,000 psi (equivalent to ~100 m gas column) up to 10,000 psi (~1,000 m gas column). Because the Muderong Shale varies in thickness (5 m to >900 m) and burial depth (~0.5–3.5 km), effective stresses and temperatures also vary. Effective stress and temperature significantly control pore geometry at different depths through compaction and diagenesis. The data from this study show that shale grain size has no direct influence over seal threshold pressure except that finer-grained Muderong Shale (36–45% particles 2.5 km) along the Northern Alpha Arch and Rankin Platform, total illite content is only moderate.

Numerical Modeling and Analysis of Nonlinear Dynamic Response for a Bolted Joint Beam Considering Interface Frictional Contact

2018 ◽  
Author(s):  
Dongwu Li ◽  
Chao Xu ◽  
Dong Wang ◽  
Lihua Wen
Keyword(s):  
Constitutive Model ◽  
Dynamic Response ◽  
Numerical Results ◽  
Experimental Results ◽  
Bolted Joints ◽  
Interface Element ◽  
Nonlinear Stiffness ◽  
Friction Contact ◽  
Structural Dynamic ◽  
Stiffness And Damping

For an assembled structure with many bolted joints, predicting its dynamic response with high fidelity is always a difficult problem, because of the nonlinearity introduced by friction contact between jointed interfaces. The friction contact results in nonlinear stiffness and damping to a structure. To realize predictive simulation in structural dynamic design, these nonlinear behaviors must be carefully considered. In this paper, the dynamics of a multi-bolt jointed beam is calculated. A modified IWAN constitutive model, which can consider both tangential micro/macro slip and nonzero residual stiffness at macroslip phase, is developed to model nonlinear contact behaviors due to joint interfaces. A whole interface element integrating the proposed constitutive model is developed. The element is used to model the nonlinear stiffness and damping caused by bolted joints. The interface element is placed between the two contact interfaces. The other part of the beam is modeled by linear beam elements. A Matlab code is developed to realize the proposed nonlinear finite element dynamic analysis method. A hammer impact experiment for the bolt-jointed beam is conducted under different excitation force levels. The calculated nonlinear numerical results are compared with experimental results. It is shown that the effect of joint nonlinearity on structural dynamics can be observed from the response predicted by the proposed method. The numerical results agree well with the experimental results. This work validates the necessary of using nonlinear joint model for dynamic simulation of jointed structures.

Dynamic Response of a Cylindrical Shell in a Potential Fluid

1979 ◽  
Vol 46 (4) ◽  
pp. 772-778 ◽  
Author(s):  
G. E. Cummings ◽  
H. Brandt
Keyword(s):  
Cylindrical Shell ◽  
Dynamic Response ◽  
Circular Cylindrical Shell ◽  
Time History ◽  
Experimental Results ◽  
Scale Model ◽  
Solution Technique ◽  
Analytical Technique ◽  
Forcing Function ◽  
Potential Fluid

A numerical solution technique is presented for determining the dynamic response of a thin, elastic, circular, cylindrical shell of constant wall thickness and density, in a potential fluid. The shell may be excited by any radial forcing function with a specified time history and spatial distribution. In addition, a pressure history may be specified over a segment of the fluid outer boundary. Any of the natural shell end conditions may be prescribed. The numerical results are compared to experimental results for a 1/12-scale model of a nuclear-reactor core-support barrel. Natural frequencies and modes are determined for this model in air, water, and oil. The computed frequencies are within 15 percent of experimental results. A sample application compares the numerical technique to an analytical solution for shell beam modes. The comparison resolves an uncertainty concerning the proper effective mass to use in the analytical technique.

Dynamic Response Simulations of Flexible Beams Using the Energy Wave Scattering Method

2005 ◽  
Vol 219 (9) ◽  
pp. 859-868
Author(s):  
T Chen
Keyword(s):  
Kinetic Energy ◽  
Potential Energy ◽  
Dynamic Response ◽  
Wave Scattering ◽  
Experimental Results ◽  
Distributed Model ◽  
Flexible Beam ◽  
Scattering Method ◽  
Flexible Beams ◽  
Good Comparison

The dynamic response of a flexible beam is simulated using the energy wave scattering method. A new topology is demonstrated to model the flexible beam and it can distinguish the displacements contributed by kinetic energy and potential energy. Experiments are conducted using both a highly distributed model and a lumped-distributed model. Numerical procedures and examples are presented. The experimental results are compared with the simulated ones and a good comparison is shown.

The Study of the Confinement Velocity in the Longitudinal Ventilation Tunnel Fire

2012 ◽  
Vol 446-449 ◽  
pp. 3665-3669
Author(s):  
Ke Qing Sun ◽  
Hui Yang
Keyword(s):  
Characteristic Parameter ◽  
Experimental Models ◽  
Experimental Results ◽  
Mixed Gas ◽  
Control Effect ◽  
Smoke Control ◽  
Tunnel Fire ◽  
Longitudinal Ventilation ◽  
The Relationship ◽  
Two Sides

For the situation that the smoke exhaust vents are located on both sides of the fire source, critical ventilation velocity is not appropriate to evaluate the smoke control effect. “Confinement velocity” is proposed as the characteristic parameter to study the longitudinal ventilation by O.Vauquelin in this situation. However, there have been few studies on confinement velocity. An experimental study was carried out on two reduced scale tunnel models. The main objective is to analysis the relationship between confinement velocity and fire heat release in this situation. Helium and air in different ratio was used as the smoke, and the "cold smoke" produced by smoke generator was put into the mixed gas in order to measure the length of smoke layer. The experimental models were based on the half tunnel as flow field at two sides of fire is symmetrical. The CFD model was created on the basis of the experiment, and the results were basically accord with the experimental results. It was shown from the experimental results that the critical point of the confinement velocity is between L / H = 2 to L / H = 4 in section 1, between L / H = 1 to L / H = 2 in section 2, rather than a fixed value; Two tunnel models had similar dimensionless confinement velocity, but the dimensionless total confinement velocity was different.

Seed germination at different temperatures and seedling emergence at different depths of Rhamnus spp

2014 ◽  
Vol 9 (5) ◽  
pp. 569-578 ◽  
Author(s):  
Hanan Aou-ouad ◽  
Hipólito Medrano ◽  
Ahmed Lamarti ◽  
Javier Gulías
Keyword(s):  
Seed Germination ◽  
Seedling Recruitment ◽  
Seedling Emergence ◽  
Burial Depth ◽  
Temperature Regimes ◽  
Mediterranean Shrubs ◽  
Different Temperatures ◽  
Temperature Ranges ◽  
Different Depths ◽  
Rhamnus Alaternus

AbstractRhamnus alaternus and R. ludovici-salvatoris, two Mediterranean shrubs with different geographic distributions, have shown important differences in seedling recruitment capacity. The objectives of this work were to determine the ability of these species to germinate seeds under different temperature ranges, as well as the capacity of seedlings to emerge from different burial depths, in order to better understand their regeneration processes. Two different experiments were performed. In the first one, seed germination was studied in Petri dishes and in the dark at different temperature regimes: a) 5–15°C, b) 10–20°C and c) 15–25°C (12h/12h). In the second experiment, seedling emergence capacity from different burial depths (0.5, 2 and 5 cm) was tested. R. ludovici-salvatoris showed a significantly higher final germination rates, a lower dormancy period, and average time response at 10–20°C than at other temperature ranges, although differences were much greater when seeds were subjected to the 5–15°C temperature regime. By contrast, R. alaternus did not show significant differences between treatments (5–15°C and 10–20°C) in germination behavior. Seedling emergence of both species was lower and slower when seeds were buried at 5 cm. However, R. ludovici-salvatoris always showed a lower seedling emergence capacity than R. alaternus at any burial depth. The low ability of R. ludovici-salvatoris to germinate seeds and emerge between 5–15°C, even from shallow depths, is discussed in relation to its low regeneration capacity and declining geographic distribution.

Effects of burial of seeds and seedlings from different seed sizes on the emergence and growth of Strophostyles helvola

1996 ◽  
Vol 74 (8) ◽  
pp. 1322-1330 ◽  
Author(s):  
Mary Yanful ◽  
M. A. Maun
Keyword(s):  
Lake Erie ◽  
Sandy Beach ◽  
Seedling Emergence ◽  
Seed Mass ◽  
Large Mass ◽  
Burial Depth ◽  
Different Depths ◽  
Mass Burial ◽  
Provincial Park

Field and greenhouse studies were conducted to examine the role of seed mass in (i) the emergence of seedlings of Strophostyles helvola (L.) Ell. from different depths of burial in sand and (ii) the ability of seedlings originating from seeds of different seed mass (weight per seed) to re-emerge from sand deposits. Seeds were sorted into four different seed mass classes (small, < 55 mg; medium, 55–65 mg; large, 65–75 mg; and extra large, > 75 mg) and sown at different depths ranging from 2 to 24 cm in sand on a sandy beach at Port Burwell Provincial Park along Lake Erie. Seeds of large mass class (65–75 mg) sown at 18 cm depth produced the largest plants. Under greenhouse conditions, all S. helvola seedlings buried to 100 and 125% of their height survived the treatment, but survival declined to 66% when they were buried to 150% of their height. Stimulation in growth was observed only when the seedlings were buried to 50 and 75% of their height. Seedlings originating from large seed masses took fewer days to re-emerge from different burial depths than seedlings from small seeds. However, the interaction term between seed mass and burial depth for the re-emergence of seedlings was not significant. Keywords: seed mass, burial of seeds, burial of seedlings, Strophostyles helvola, seedling emergence.

Blast Resistance of Clamped Cylindrical Sandwich Shells with Metallic Foam Cores

2013 ◽  
Vol 535-536 ◽  
pp. 461-464 ◽  
Author(s):  
Lin Jing ◽  
Zhi Hua Wang ◽  
Long Mao Zhao ◽  
V.P.W. Shim
Keyword(s):  
Dynamic Response ◽  
Failure Modes ◽  
Blast Resistance ◽  
Sheet Thickness ◽  
Structural Response ◽  
Experimental Results ◽  
Metallic Foam ◽  
Pendulum System ◽  
Sandwich Shells ◽  
Structural Configurations

The deformation/failure modes and dynamic response of fully clamped cylindrical sandwich shells with aluminum foam cores subjected to air blast loading were investigated experimentally. A four-cable ballistic pendulum system was employed to measure the impulse imparted to the blast-loaded specimen. The deformation/failure modes of specimens were classified and analyzed, the effects of face-sheet thickness, core relative density, specimen curvature and mass of charge on the structural response of metallic sandwich shells were examined. Experimental results indicate that both the deformation/failure modes and the dynamic response of the sandwich shells are sensitive to the structural configurations and blast impulse. The experimental results are useful for validating theoretical predictions, as well as in engineering applications of cellular metal sandwich structures.

scholarly journals Theoretical and experimental analysis of the exact receptance function of a clamped-clamped beam with concentrated masses

2020 ◽  
Author(s):  
Nguyen Viet Khoa ◽  
Dao Thi Bich Thao
Keyword(s):  
Dynamic Response ◽  
Numerical Simulations ◽  
Experimental Analysis ◽  
Arbitrary Point ◽  
Peak Position ◽  
Numerical Results ◽  
Experimental Results ◽  
Harmonic Force ◽  
Concentrated Masses

This paper establishes the exact receptance function of a clamped-clamped beam carrying concentrated masses. In this paper, the derivation of exact receptance and numerical simulations are provided. The proposed receptance function is convenient to apply for predicting the dynamic response at arbitrary point of the beam acted by a harmonic force applied at arbitrary point. The influence of the concentrated masses on the receptance is investigated. The numerical simulations show that a peak in the receptance decreases when there is a mass located close to that peak position. The numerical results have been compared to the experimental results has to justify the theory.

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