Band gap characteristics of friction stir additive manufactured phononic crystals

2022 ◽  
Author(s):  
Z.J. Tan ◽  
Zhao Zhang
Keyword(s):  
Additive Manufacturing ◽  
Band Gap ◽  
Temperature Rise ◽  
Phononic Crystals ◽  
Inertia Moment ◽  
Welding Temperature ◽  
Rotating Speed ◽  
Friction Stir ◽  
Gap Characteristics ◽  
Lower Temperature

Abstract Additive Manufacturing (AM) is widely used to fabricate phononic crystals (PnCs) in recent years. Friction Stir Additive Manufacturing (FSAM) is a new-type solid state fabrication technology which is fusion free with low distortions. FSAM was selected to fabricate the designed PnCs. The manufactured specimen was distorted due to the temperature rise in the manufacturing process and the band gaps (BGs) were changed with the distortions. Results indicate that the band gap of the PnCs moves to be in higher frequency domain due to the residual distortions of the manufactured PnCs. The residual distortion of FSAM PnCs is 2.77 times smaller in comparison with the Tungsten Inert Gas (TIG) welding. So, the differences of the band gap between the designed PnCs and the FSAM specimen are only in the range of 0.15%- 0.55% due to the lower temperature rise in FSAM. The further analysis shows that the change of the BGs is caused by the growth of the inertia moment for the FSAM PnCs. With the increase of the rotating speed in FSAM, the residual distortion of the FSAM PnCs is increased due to the increase of the welding temperature. This can lead to the increase of the inertia moment, which is the key reason for the increase of the BG characteristics of the FSAM PnCs.

scholarly journals Microstructural Characterization and Mechanical Properties of Similar and Dissimilar Al Alloys Joined using Friction Stir Welding

2018 ◽  
Vol 14 (1) ◽  
pp. 19-28
Author(s):  
Kharia Salman Hassan
Keyword(s):  
Friction Stir Welding ◽  
Welding Speed ◽  
Shot Peening ◽  
Rotational Speed ◽  
Microstructural Characterization ◽  
Tensile Tests ◽  
Welding Parameters ◽  
Welding Temperature ◽  
Rotating Speed ◽  
Friction Stir

The influence of pre- shot peening and welding parameters on mechanical and metallurgical properties of dissimilar and similar aluminum alloys AA2024-T3 and AA6061-T6 joints using friction stir welding have been studied. In this work, numbers of plates were equipped from sheet alloys in dimensions (150*50*6) mm then some of them were exposed to shot peening process before friction stir welding using steel ball having diameter 1.25 mm for period of 15 minutes. FSW joints were manufactured from plates at three welding speeds (28, 40, 56 mm/min) and welding speed 40mm/min was chosen at a rotating speed of 1400 rpm for welding the dissimilar pre- shot plates. Tow joints were made at rotational speed of 1000 rpm and welding speed of 40m/min from shot and without shot peening plats. Welding temperature was measured in three zones using thermocouple. Micro hardness (HV) and tensile tests were performed to evaluate the mechanical characteristic of the joints. The results show a decay in mechanical qualities when the welding speed was increased and the best result was at (28) mm/min and the opposite result was obtained when rotational speed increased and pre-shot contributed in improving of this decay at 88% of welding speed (40) mm/min and 98%  at the rotational speed of 1000 rpm.      

scholarly journals A Multi Scale Strategy for Simulation of Microstructural Evolutions in Friction Stir Welding of Duplex Titanium Alloy

2019 ◽  
Vol 38 (2019) ◽  
pp. 485-497 ◽  
Author(s):  
Z. Zhang ◽  
Z. J. Tan
Keyword(s):  
Friction Stir Welding ◽  
Volume Fraction ◽  
Average Length ◽  
Transformation Model ◽  
Scale Model ◽  
Welding Temperature ◽  
Rotating Speed ◽  
Friction Stir ◽  
Multi Scale ◽  
Translational Speed

AbstractA fully coupled thermo-mechanical model is established to simulate the temperature variations and the material deformations in friction stir welding (FSW) of Ti-6Al-4V. The extracted data are used for further simulation on microstructural evolutions. A multi scale model, which consists of the grain growth model in grain cluster scale and the phase transformation model in one grain scale, is proposed. The nuclei of α and β phases, the recrystallizations and the grain growths are systematically investigated. Comparisons with experimental data and experimental observations can validate the newly proposed microstructural evolution model for Ti-6Al-4V. Results indicate that the volume fractions of α and β phases can be directly determined by the cooling rates in FSW process. With the increase of the rotating speed, the volume fraction of α phase is increased and β phase decreased due to the increase of welding temperature. With the decrease of the translational speed, the volume fraction of α phase gets bigger and β phase smaller. The acicular α grain can be generated on the β grain boundaries and grows along <1 1 0> direction on β substrate. The average length of α grain can be increased with longer cooling time and decreased with lower rotating speed or higher translational speed.

scholarly journals The Influences of Process Parameters on the Preparation of Closed-cell Aluminum foam by Friction Stir Processing

2021 ◽  
Author(s):  
Qiu Pang ◽  
Zhengjian Wu ◽  
Zhili Hu
Keyword(s):  
Base Metal ◽  
Process Parameters ◽  
Friction Stir Processing ◽  
Aluminum Matrix ◽  
Maximum Temperature ◽  
Welding Temperature ◽  
Rotating Speed ◽  
Friction Stir ◽  
Closed Cell ◽  
Al Foam

Abstract In the present investigation, the closed-cell Al foam was fabricated by friction stir processing (FSP) combined with heat treatment. The influences of process parameters on microstructures of closed-cell Al foam precursor were investigated by optical metallographic microscope and scanning electronic microscope (OM/SEM). Fluent CFD software was developed to simulate the temperature field and flow field in friction stir processing. The cupping test values were compared for base metal and different weld passes. The results show that the welding speeds have little effect on the mixing of powder in the stir zone because of the relatively small welding heat input. However, the pore size and pore morphology are highly sensitive to change in the rotating speeds. When the welding speed is 50mm/min and the rotating speed is 2000rpm, the powder ring is continuous and uniform due to sufficient plastic deformation and flow. When the foaming time is 110s, the expansion rate of the whole foam increases rapidly, and the diameter of the pore is uniform. Numerical simulation shows that the welding heat mainly comes from the shoulder of the stirring head and the welding temperature peak appears near the stirring pin. The maximum flow velocity appears at the outer edge of the shaft shoulder in which the aluminum matrix is softened preferentially. When the rotating speed increases to 2000r/min, the velocity of the outermost edge of the shaft shoulder increases by 59.96%, and the maximum temperature at the stirring pin reaches 491℃ which is consistent with the experimental results. The formability of the joint interface is improved. The cupping test values increase with the increase of deformation temperature. Especially the cupping test value of foamed preform is close to that of base metal at 450℃.

Band Gap Characteristics of Phononic Crystal Made from Different Material

2015 ◽  
Vol 723 ◽  
pp. 778-784 ◽  
Author(s):  
Xin Yan
Keyword(s):  
Band Gap ◽  
Theoretical Basis ◽  
Phononic Crystal ◽  
Wide Band ◽  
Phononic Crystals ◽  
Transmission Matrix ◽  
Wide Band Gap ◽  
One Dimensional ◽  
Gap Characteristics ◽  
Transmission Matrix Method

The band gap characteristics of phononic crystal is influenced by material and structure etc. Based on the transmission matrix method, the first band gap characteristics of one-dimensional phononic crystal were numerical simulation with different ratio, and these phononic crystals were made form aluminum, lead, steel, carbon and epoxy resin materials. These results show that phononic crystal structure made from high density materilal are more easier to form wide band gap, and there are also more easier to form wide band gap under the same proportion. These results provide theoretical basis for the design of one-dimensional phononic crystal devices.

Band Gap Properties of Piezoelectric/Viscous Liquid Phononic Crystals

2011 ◽  
Author(s):  
Yi-Ze Wang ◽  
Kazuaki Inaba ◽  
Feng-Ming Li ◽  
Kikuo Kishimoto
Keyword(s):  
Band Gap ◽  
Viscous Liquid ◽  
Phononic Crystals ◽  
Viscous Damping ◽  
Viscous Effects ◽  
Filling Fraction ◽  
Damping Parameter ◽  
Out Of Plane ◽  
Gap Characteristics ◽  
Gap Width

The viscous effects on the band gap characteristics of the piezoelectric/viscous liquid phononic crystals are studied. The expressions of the generalized eigenvalue equation for the cylindrical phononic crystals are derived. Numerical calculations are performed to discuss the band gap characteristics with different filling ratios and viscous damping parameters. Form the results, it can be observed that the out-of-plane mode will appear, which caused by the viscous effects. Both of the real and imaginary parts of frequencies will increase with the filling fraction becoming larger. The maximum of the normalized band gap width is achieved by f = 0.5. Furthermore, the band gap edges become higher with the viscous damping parameter increasing, especially for higher band gaps.

scholarly journals Research on the Band Gap Characteristics of Two-Dimensional Phononic Crystals Microcavity with Local Resonant Structure

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Mao Liu ◽  
Pei Li ◽  
Yongteng Zhong ◽  
Jiawei Xiang
Keyword(s):  
Band Gap ◽  
Phononic Crystal ◽  
Engineering Application ◽  
Low Frequency ◽  
Phononic Crystals ◽  
Band Gaps ◽  
Wave Band ◽  
Two Dimensional ◽  
Frequency Range ◽  
Gap Characteristics

A new two-dimensional locally resonant phononic crystal with microcavity structure is proposed. The acoustic wave band gap characteristics of this new structure are studied using finite element method. At the same time, the corresponding displacement eigenmodes of the band edges of the lowest band gap and the transmission spectrum are calculated. The results proved that phononic crystals with microcavity structure exhibited complete band gaps in low-frequency range. The eigenfrequency of the lower edge of the first gap is lower than no microcavity structure. However, for no microcavity structure type of quadrilateral phononic crystal plate, the second band gap disappeared and the frequency range of the first band gap is relatively narrow. The main reason for appearing low-frequency band gaps is that the proposed phononic crystal introduced the local resonant microcavity structure. This study provides a good support for engineering application such as low-frequency vibration attenuation and noise control.

Sign in / Sign up

Export Citation Format

Share Document