scholarly journals Research of Statistical Characteristics of Target Strength of a Single-layer Cylindrical Shell with Random Coating

2018 ◽  
Vol 171 ◽  
pp. 012023
Author(s):  
Hu Bo
Keyword(s):  
Cylindrical Shell ◽  
Single Layer ◽  
Statistical Characteristics ◽  
Target Strength

scholarly journals Vibration analysis of a sandwich cylindrical shell in hygrothermal environment

2021 ◽  
Vol 10 (1) ◽  
pp. 414-430
Author(s):  
Chunwei Zhang ◽  
Qiao Jin ◽  
Yansheng Song ◽  
Jingli Wang ◽  
Li Sun ◽  
...  
Keyword(s):  
Cylindrical Shell ◽  
Natural Frequency ◽  
Equations Of Motion ◽  
Single Layer ◽  
Functionally Graded ◽  
Sandwich Shell ◽  
Continuous Change ◽  
Multilayered Structures ◽  
Cylindrical Sandwich Shell ◽  
Vibrational Behavior

Abstract The sandwich structures are three- or multilayered structures such that their mechanical properties are better than each single layer. In the current research, a three-layered cylindrical shell including a functionally graded porous core and two reinforced nanocomposite face sheets resting on the Pasternak foundation is used as model to provide a comprehensive understanding of vibrational behavior of such structures. The core is made of limestone, while the epoxy is utilized as the top and bottom layers’ matrix phase and also it is reinforced by the graphene nanoplatelets (GNPs). The pattern of the GNPs dispersion and the pores distribution play a crucial role at the continuous change of the layers’ properties. The sinusoidal shear deformation shells theory and the Hamilton’s principle are employed to derive the equations of motion for the mentioned cylindrical sandwich shell. Ultimately, the impacts of the model’s geometry, foundation moduli, mode number, and deviatory radius on the vibrational behavior are investigated and discussed. It is revealed that the natural frequency and rotation angle of the sandwich shell are directly related. Moreover, mid-radius to thickness ratio enhancement results in the natural frequency reduction. The results of this study can be helpful for the future investigations in such a broad context. Furthermore, for the pipe factories current study can be effective at their designing procedure.

scholarly journals Simulation and analysis on low-frequency scattering characteristics of the finite cylindrical shell in shallow water

2019 ◽  
Vol 283 ◽  
pp. 03007
Author(s):  
Jinyu Li ◽  
Dejiang Shang ◽  
Yan Xiao
Keyword(s):  
Cylindrical Shell ◽  
Free Space ◽  
Acoustic Scattering ◽  
Low Frequency ◽  
Target Strength ◽  
Wave Direction ◽  
Scattering Field ◽  
Simulation Results ◽  
Finite Cylindrical Shell ◽  
Target Locations

Low-frequency acoustic scatterings from a finite cylindrical shell are numerically analyzed by FEM. The simulation results show that the acoustic-scattering field in waveguide has lots of frequency-related sidelobes, while no sidelobes exist in free space at low frequencies. The simulation also indicates that the module value in waveguide can be almost 20 dB larger than that in free space at low frequency, which is caused by the ocean boundaries. We also demonstrate that when the incident wave direction is normal to the target at low frequency, the target strength will be maximum and the distribution of the acoustic-scattering field is axisymmetric about the incident waving direction. Meanwhile, the acoustic-scattering field is also related to the impedance of the seabed, and the change of the impedance makes just a little contribution to the scattering field. Finally, the influence of different target locations is analyzed, including the targets near the sea surface, seabed and the middle region of the ocean waveguide, respectively. From simulation results, it is evident that the distribution of the acoustic-scattering field at low frequency has a little difference, which is smaller than 0.5 dB with various target locations, and the change is frequency and boundary-related.

Nonlinear Buckling Analysis of Long-Span Suspended Latticed Intersected Cylindrical Shell

2014 ◽  
Vol 919-921 ◽  
pp. 169-176 ◽  
Author(s):  
Ming Liang Zhu ◽  
Yan Sun
Keyword(s):  
Cylindrical Shell ◽  
Bearing Capacity ◽  
Single Layer ◽  
Ultimate Bearing Capacity ◽  
Buckling Analysis ◽  
Nonlinear Buckling ◽  
Long Span ◽  
The Stability ◽  
Nonlinear Buckling Analysis ◽  
Material Nonlinear

The Suspended Latticed Intersected Cylindrical Shell (SLICS) is a new structural system, composed by the single layer Latticed Intersected Cylindrical Shell (LICS) and the prestressed cable-strut system. Mechanical properties of this structure were investigated through nonlinear buckling analysis by the consistent imperfect buckling analysis method, compared with the single layer LICS. Structure parameters including prestress level, member section, length of bar, rise-span ratio, obliquity were analyzed. And the effect of material nonlinearity on the stability was studied. Results show that the ultimate bearing capacity of the SLICS is improved as the introduction of prestress. However the prestress level has a limited impact on the ultimate bearing capacity. And the material nonlinear is very important to the stability of the SLICS.

Dynamic loading experiment performed on a wooden single layer two-way grid cylindrical shell roof

2002 ◽  
pp. 1: 519-528
Author(s):  
T. Furukawa ◽  
K. Imai ◽  
M. Fujimoto ◽  
N. Komedani ◽  
R. Inoue ◽  
...  
Keyword(s):  
Cylindrical Shell ◽  
Dynamic Loading ◽  
Single Layer

scholarly journals The influence of uncertainty in target strength on abundance indices based on acoustic surveys: examples of the Baltic Sea herring and sprat

2009 ◽  
Vol 66 (6) ◽  
pp. 1404-1409 ◽  
Author(s):  
Svetlana M. Kasatkina
Keyword(s):  
Baltic Sea ◽  
Size Structure ◽  
Stock Assessment ◽  
Clupea Harengus ◽  
Statistical Characteristics ◽  
Target Strength ◽  
The Baltic Sea ◽  
Abundance Indices ◽  
Acoustic Surveys ◽  
The Baltic

Abstract Kasatkina, S. M. 2009. The influence of uncertainty in target strength on abundance indices based on acoustic surveys: examples of the Baltic Sea herring and sprat. – ICES Journal of Marine Science, 66: 1404–1409. In situ, target-strength (TS) measurements at 38 kHz and an analysis of biometric fish characteristics are presented for the Baltic Sea herring (Clupea harengus membras) and sprat (Sprattus sprattus). It is demonstrated that the application of two TS–length functions for the Baltic Sea clupeids, the first for young herring and sprat and the second for adult herring, is reasonable, and the two functions can therefore replace the well-known equation used since 1983. Parameters of the proposed relationships, accompanied by their statistical characteristics, are included in a model to obtain uncertainty in acoustically derived abundance indices. Major components of survey uncertainty, such as spatial variability, species composition, and size structure, are also included in the simulation. The proposed TS functions should permit estimates of more realistic abundance dynamics of Baltic Sea clupeids, by years and age groups, thereby providing important information for stock assessment models.

Sign in / Sign up

Export Citation Format

Share Document