The elastic wave in a thin-walled vessel and its role in relation to the low-velocity detonation regime

1970 ◽  
Vol 6 (3) ◽  
pp. 304-310
Author(s):  
O. K. Rozanov ◽  
A. N. Dremin
Keyword(s):  
Elastic Wave ◽  
Detonation Regime ◽  
Low Velocity ◽  
Thin Walled

Energy absorbed ability and damage analysis for honeycomb sandwich material of bio-inspired micro aerial vehicle under low velocity impact

2020 ◽  
pp. 095440622097542
Author(s):  
Jianxun Du ◽  
Peng Hao ◽  
Mabao Liu ◽  
Rui Xue ◽  
Lin’an Li
Keyword(s):  
Honeycomb Structure ◽  
Low Velocity Impact ◽  
Parameter Study ◽  
Low Velocity ◽  
Micro Aerial Vehicle ◽  
Thin Walled Structures ◽  
Wide Range ◽  
Aerial Vehicle ◽  
Thin Walled ◽  
The Impact

Because of the advantages of light weight, small size, and good maneuverability, the bio-inspired micro aerial vehicle has a wide range of application prospects and development potential in military and civil areas, and has become one of the research hotspots in the future aviation field. The beetle’s elytra possess high strength and provide the protection of the abdomen while being functional to guarantee its flight performance. In this study, the internal microstructure of beetle’s elytra was observed by scanning electron microscope (SEM), and a variety of bionic thin-walled structures were proposed and modelled. The energy absorption characteristics and protective performance of different configurations of thin-walled structures with hollow columns under impact loading was analyzed by finite element method. The parameter study was carried out to show the influence of the velocity of impactor, the impact angle of the impactor and the wall thickness of honeycomb structure. This study provides an important inspiration for the design of the protective structure of the micro aerial vehicle.

Combined viscoelastic and elastic wave dissipation mechanism at low velocity impact

2016 ◽  
Vol 27 (4) ◽  
pp. 1244-1250 ◽  
Author(s):  
Sergej Aman ◽  
Peter Mueller ◽  
Juergen Tomas ◽  
Sergii Kozhar ◽  
Maksym Dosta ◽  
...  
Keyword(s):  
Elastic Wave ◽  
Low Velocity Impact ◽  
Wave Dissipation ◽  
Low Velocity ◽  
Velocity Impact ◽  
Dissipation Mechanism

ELASTIC‐WAVE VELOCITY MEASUREMENTS IN ROCKS AND OTHER MATERIALS BY PHASE‐DELAY METHODS

Geophysics ◽  
1975 ◽  
Vol 40 (6) ◽  
pp. 955-960 ◽  
Author(s):  
E. A. Kaarsberg
Keyword(s):  
Elastic Wave ◽  
Wave Velocity ◽  
Path Length ◽  
Shear Velocity ◽  
Elastic Wave Velocity ◽  
Phase Delay ◽  
Velocity Measurements ◽  
Multiple Reflections ◽  
Low Velocity ◽  
High Attenuation

The phase delay of a continuous sinusoidal elastic wave after transmission through a medium may be used to determine the velocity of propagation of the wave in the medium. The change in path length for a given frequency, or the change in frequency for a given path length, required to change the phase delay by integral multiples of 360 degrees is measured in the laboratory by the use of source and receiver piezoelectric transducers whose signals are applied to the horizontal and vertical deflection circuits of an oscilloscope. The accuracy of the method depends upon the accuracy with which the frequency of the transmitted wave and its path length through the medium (or change in path length) can be determined, provided the effect of extraneous signals (e.g., boundary reflections, multiple reflections, alternate modes of propagation, etc.) is negligible. The phase‐delay methods are illustrated and compared with conventional pulse methods by using both to make compressional‐velocity measurements in water and compressional‐ and shear‐velocity measurements in a high velocity basalt and in a low velocity dried mud sample. The results of the two methods agree to within a few percent. It is suggested that these phase‐delay methods may be especially well‐suited for making elastic‐wave velocity measurements in media with high attenuation of the waves propagated in them.

scholarly journals Analysis Numerical Discontinuity of Thin Walled Tube Subjected Low Velocity Impact

2018 ◽  
Vol 4 ◽  
Author(s):  
Bismil Rabeta ◽  
Sahril Afandi Sitompul
Keyword(s):  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
Thin Walled Tube ◽  
Thin Walled

scholarly journals Energy absorption of thin-walled cylinders filled with silicone rubber subjected to low-velocity impact

2017 ◽  
Vol 4 (5) ◽  
pp. 17-00052-17-00052
Author(s):  
Tadaharu ADACHI ◽  
Takeru OZAWA ◽  
Hardi WITONO ◽  
Sho ONISHI ◽  
Yosuke ISHII
Keyword(s):  
Energy Absorption ◽  
Silicone Rubber ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
Thin Walled

Evolution of Fatigue Damage in Wheel-Loading Tests Evaluated by 3D Elastic-Wave Tomography

2017 ◽  
Vol 12 (3) ◽  
pp. 487-495 ◽  
Author(s):  
Tomoki Shiotani Hisafumi Asaue ◽  
◽  
Takahiro Nishida ◽  
Takuya Maeshima ◽  
Yasushi Tanaka ◽  
...  
Keyword(s):  
Elastic Wave ◽  
Fatigue Damage ◽  
Heavy Traffic ◽  
Three Dimensional ◽  
Critical Issue ◽  
Concrete Slabs ◽  
Internal Defects ◽  
Low Velocity ◽  
Wave Tomography ◽  
Wheel Loading

Currently, for proper maintenance of infrastructures, preventive and proactive measures for prognosis of infrastructures are preferable in comparison with reactive/corrective maintenances of structures that are highly deteriorated. This is so because vast sums are generally necessary for recovering the performance of the highly damaged structures. Therefore, prognostic maintenance must be conducted to establish economic and efficient management systems for the existing concrete infrastructures to complete their designed service life and to even extend them. Severe deterioration of aging infrastructures is currently a critical issue. In particular, the damage and deterioration of concrete slabs in bridges and highways are regarded as a critical issue worldwide. These components are often so fatigue-damaged under conditions of heavy traffic that repair and retrofit work definitely require regulating the traffic, thereby severely disrupting their function for the users. Consequently, preventive and proactive maintenances of concrete slabs that are in service are being urgently demanded for establishing the prognosis for civil engineering. To decide the maintenance systems based on the prognosis of concrete slabs, evolution of the fatigue damage and internal defects should be evaluated properly, if possible, visually. In this respect, Acoustic Emission (AE) tomography and elastic-wave tomography is under investigation and development as innovative nondestructive testing (NDT) methods. By determining the three-dimensional velocity distribution inside a slab via the above methods, the damaged or deteriorated areas are identified. Until now, regulated on-site visual inspections are only performed for the slab components of in-service infrastructures. However, the recent methods can predict the internal defects before the deteriorations physically emerge on the surface. Therefore, inspection methods to identify internal defects in concrete are to be readily implemented prior to the repair works. In the present work, a comparative study is performed during the internal progress of the fatigue damage induced by wheel-loading to identify the damaged area quantitatively via elastic-wave tomography, followed by a comparison with resultant surface crack conditions. The results show a good agreement between the predicted low-velocity zones and the damaged areas estimated by crack distributions, displacements, and strains. In particular, at locations where cracks are intensely observed, the velocities decrease below 3400 m/s. Furthermore, the areas with velocities below 2700 m/s are also observed in the slab corresponding to the attainment of the fatigue limit.

Low-velocity impact response of active thin-walled hybrid composite structures embedded with SMA wires

2007 ◽  
Vol 45 (9) ◽  
pp. 799-808 ◽  
Author(s):  
S.M.R. Khalili ◽  
A. Shokuhfar ◽  
K. Malekzadeh ◽  
F. Ashenai Ghasemi
Keyword(s):  
Hybrid Composite ◽  
Composite Structures ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
Thin Walled
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