Acoustic scattering from stainless steel shells with varying wall thickness using a biomimetic click: Modeling and interpretation

2017 ◽  
Vol 141 (5) ◽  
pp. 3845-3845
Author(s):  
Gang Qiao ◽  
Xin Qing ◽  
Donghu Nie
Keyword(s):  
Stainless Steel ◽  
Wall Thickness ◽  
Acoustic Scattering

Acoustic Scattering from Bi-Layered Cylindrical Shells: Influence of the Layers Thicknesses on the Guided Waves

2019 ◽  
Vol 105 (6) ◽  
pp. 1251-1257
Author(s):  
Younes Khandouch ◽  
El Houcein Aassif ◽  
Said Agounad
Keyword(s):  
Stainless Steel ◽  
Guided Waves ◽  
Shape Change ◽  
Cylindrical Shells ◽  
Acoustic Scattering ◽  
Modal Identification ◽  
Current Work ◽  
Geometrical Characteristics ◽  
Cutoff Frequencies

The current work focuses on the study of acoustic scattering from bi-layered stainless steel-copper and copper-stainless steel cylindrical shells filled with air and immersed in water. This paper is interested in revealing the effects of physical and geometrical characteristics of the layers constituting the shells on the scattering phenomenon. The object of this work, is to study the influence of the layers thicknesses on guided waves, the overall thickness of the shells is fixed. The plane of modal identification was chosen to analyze the scattering phenomenon. We investigate the resonance trajectories of the guided waves, especially the curves change. The investigation and comparison made on resonance trajectories, show a shape change, a gradual deviation, or both, appear on the resonance trajectories of different guided waves, for the reduced cutoff frequencies of guided waves a sliding to higher and lower value are noticed. The interaction between guided waves is also manifested in the scattering phenomenon. The findings for the bi-layered cylindrical shells are then compared with those obtained for the mono-layered stainless steel and copper cylindrical shells. Then, this work is completed by an investigation on the reduced cut-off frequencies of the A1 wave, that have been extracted for different possible values of the intermediary radius. In this part, to understand the observed phenomena, other examples of bi-layered cylindrical shells are introduced. The obtained results are analyzed and investigated.

scholarly journals Development of Process Induced Residual Stress During Flow Forming of Tubular 15-5 Martensitic Stainless Steel

2017 ◽  
Author(s):  
Saber Khayatzadeh ◽  
Shanmukha Rao Moturu ◽  
Joe F. Kelleher ◽  
Salah Rahimi
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Neutron Diffraction ◽  
Wall Thickness ◽  
Hole Drilling ◽  
Forming Process ◽  
Flow Forming ◽  
Stress Components ◽  
Axial Residual Stress ◽  
Original Part

Flow forming is a near net shape process for manufacturing of dimensionally accurate hollow components such as shaft in gas turbines, that is currently at its development stage for aerospace industry. The process has several advantages such as reducing material wastage, extremely fast manufacturing time, and eliminating extra manufacturing processes such as machining. Due to the nature of this complicated cold deformation process, significant magnitude of residual stress is introduced into the component. Understanding the magnitude and distribution of residual stress is essential to tailor the flow forming process to achieve parts within dimensional tolerances and desired mechanical properties. The present research is aiming to explore the generation and evolution of residual stress at various stages of flow forming process in a tubular component made from martensitic 15Cr-5Ni stainless steel, using different techniques of neutron scattering, x-ray diffraction (XRD) and hole-drilling based on electronic speckle pattern interferometry (ESPI). Residual stress measurements were carried out in preformed and flow formed components at surface, near-surface and in the bulk of components using XRD, ESPI based hole-drilling and neutron diffraction techniques. These measurements were conducted at different levels of reduction in the thickness of the original part (i.e. after 20% and 40%), by applying identical forming parameters for all samples. The XRD results show significant change in hoop and axial residual stress levels with a reduction in the wall thickness. This is more pronounced for the axial component where the average stress switches from relatively high tensile (∼ 450MPa) in the original part to significant compressive stress (∼ −600MPa) in the formed part, after 20% of reduction. The bulk residual stress components measured in the middle of thickness of the parts, using neutron scattering, show a general increase in the magnitude of residual stress by higher level of deformation (i.e. reduction in the wall thickness). The measured bulk stress components through the thickness were tuned to tensile after reducing the wall thickness by 40%. The results of XRD and neutron diffraction stress measurements suggest that the residual stress along the length of the samples (i.e. axial direction) is consistent with ±800 MPa and ±400 MPa after 20% and 40% reduction by forming process, respectively. The results of ESPI based hole-drilling show tensile hoop residual stress (≈600 MPa) and an abrupt fluctuation (i.e. tension-compressive-tension) in the axial residual stress near the surface of the part following flow forming. The stresses measured by ESPI based hole-drilling are complementary to the results of the XRD on surface and neutron diffraction in the bulk to reconstruct the residual stress profile form the surface through to the bulk.

A Study of Effects of Pipe Geometry on FAD Curves for Austenitic Stainless Steel and Ferritic Steel Piping Materials

1998 ◽  
Vol 120 (1) ◽  
pp. 86-92 ◽  
Author(s):  
R. Mohan ◽  
G. M. Wilkowski ◽  
R. Bass ◽  
J. M. Bloom
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Wall Thickness ◽  
Ferritic Steel ◽  
Three Dimensional ◽  
Pipe Geometry ◽  
Element Method ◽  
Steel Piping

A comprehensive study of failure assessment diagrams for circumferentially surface-cracked austenitic stainless and ferritic steel pipes was conducted with the use of the finite element method (FEM). While the majority of the analyses were conducted using the line-spring/shell finite element method, some three-dimensional finite element analyses, conducted independently, are also reported in this paper. Comparison of the predictions of the line-spring/shell and three-dimensional analyses reinforce the validity of the former approach for surface-cracked pipes. The results indicated that the ASME Code Case N-494-2 applicable for ferritic steel piping appears reasonably conservative even for pipes with mean radius-to-wall thickness ratios of 20, whereas the results showed that the newly adopted Code Case N-494-3 for austenitic stainless steel piping requires a limit for pipe with mean radius-to-wall thickness ratios larger than 15. For consistency, the limitation of Rm/t ≤ 15 was incorporated in the approved final version of Code Case N-494-3, and was incorporated in Code Case N-494-2 as well. Because these Code cases are applicable only to Class 1 primary nuclear piping, which typically has values of Rm/t ≤ 15, this is not a significant limitation. It was also shown that the choice of definitions of membrane and bending stresses as well as the choice of F1 function values in calculating the elastic part of the J integral have a profound effect on the resulting FAD curves.

Research of Machining Process on 17-4PH Stainless Steel Superfine Deep-Hole Drilling

2014 ◽  
Vol 633-634 ◽  
pp. 688-692 ◽  
Author(s):  
Zhan Feng Liu ◽  
Han Chen Wang
Keyword(s):  
Stainless Steel ◽  
Wall Thickness ◽  
Machining Process ◽  
New Method ◽  
Hole Drilling ◽  
Drilling Process ◽  
Deep Hole ◽  
Deep Hole Drilling ◽  
Gun Drill

Through the analysis of superfine deep-hole drilling process, we used the combination of gun drill and BTA deep-hole drilling process for 17-4PH (0Cr17Ni4Cu4Nb) stainless steel deep-hole drilling test. We measured wall thickness point by point, and calculated the conversion of the eccentricity in a deviation axis line. Which fully embodies the advantage of this process for stainless steel 17-4PH, and provides a new method in super hardness material deep-hole drilling field.

Effect of Wall Thickness of the Billet on 1Cr18Ni9 Stainless Steel Tube Stagger Spinning Process

2014 ◽  
Vol 852 ◽  
pp. 244-247
Author(s):  
Shu Heng Yang ◽  
Xue Li Wang
Keyword(s):  
Finite Element Method ◽  
Stainless Steel ◽  
Wall Thickness ◽  
Metal Flow ◽  
Steel Tube ◽  
Stainless Steel Tube ◽  
Flow Rule ◽  
Spinning Process ◽  
Inner Diameter ◽  
Spinning Force

The stagger spinning process of 1Cr18Ni9 tube was investigated by using finite element method. The metal flow rule around the roller during the tube stagger spinning was analyzed. The influences of wall thickness of the billet on effective stress and spinning force were studied using software Deform. The simulated results indicate that the proper wall thickness of the billet should be 8~15 mm, for the billet with length of 100mm and inner diameter of 200mm.

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