scholarly journals Novel Approach to The Design of Sound Insulating Composites by Means of a Non-linearly Extrapolated Master Curve

2018 ◽  
Vol 12 (1) ◽  
pp. 14-28
Author(s):  
Cecchini Federico ◽  
Cherubini Valeria ◽  
Francesco Fabbrocino ◽  
Francesca Nanni
Keyword(s):  
Smart Materials ◽  
Composite Structures ◽  
Transmission Loss ◽  
Weight Ratio ◽  
Shear Thickening ◽  
Sound Insulation ◽  
Commercial Vehicles ◽  
Shear Rates ◽  
Novel Approach ◽  
Shear Thickening Fluids

Background:The increasing use of composite structures with a high stiffness-to-weight ratio in commercial vehicles has brought about a reduction in fuel consumption but, on the other hand, has significantly increased noise transmission particularly in case of thin and lightweight structures. Noise is a primary issue for commercial vehicles, such as airplanes, helicopters and cars. The present research deals with the use of smart materials, as Shear-Thickening Fluids (STF, or dilatants) in view of manufacturing elements with increased sound insulation properties.Methods:The response of a sandwich material with the STF core was investigated both experimentally and numerically, by choosing the Sound Transmission Loss (STL) of the composite structure as the figure of merit.The experimental investigation was focused on the manufacturing of a sandwich structure made of metallic skins and a STF core that was successively characterized by sound insertion loss measurement.The numerical investigation was carried out by using a Generalized Transfer Matrix Method (GTMM) and a Statistical Energy Analysis (SEA) in view of selecting the fluid capable of granting the highest acoustic transmission loss.Results:Finally, the test results were compared to the numerical results, showing a noticeable agreement. The used STF showed increasing viscosity at increasing shear rates.

scholarly journals A phenomenological theory-based viscosity model for shear thickening fluids

2021 ◽  
Author(s):  
Kun Lin ◽  
Jiapeng Qi ◽  
Hongjun Liu ◽  
Minghai Wei ◽  
Hua Yi Peng
Keyword(s):  
Experimental Data ◽  
Impact Resistance ◽  
Shear Thickening ◽  
Phenomenological Theory ◽  
Logistic Function ◽  
Viscosity Model ◽  
Model Parameters ◽  
Shear Rates ◽  
Marquardt Algorithm ◽  
Shear Thickening Fluids

Abstract A viscosity model for shear thickening fluids (STFs) based on phenomenological theory is proposed. The model considers three characteristic regions of the typical material properties of STFs: a shear thinning region at low shear rates, followed by a sharp increase in viscosity above the critical shear rate, and subsequently a significant failure region at high shear rates. The typical S-shaped characteristic of the STF viscosity curve is represented using the logistic function, and suitable constraints are applied to satisfy the continuity of the viscosity model. Then, the Levenberg–Marquardt algorithm is introduced to fit the constitutive model parameters based on experimental data. Verification against experimental data shows that the model can predict the viscosity behavior of STF systems composed of different materials with different mass concentrations and temperatures. The proposed viscosity model provides a calculation basis for the engineering applications of STFs (e.g., in increasing impact resistance and reducing vibration).

Impact studies of shear thickening fluids incorporated within composite structures

2011 ◽  
Vol 2 (2) ◽  
pp. 136 ◽  
Author(s):  
C. Trigg ◽  
A. Dyke ◽  
J. Davies ◽  
M. Dunleavy ◽  
N. Park ◽  
...  
Keyword(s):  
Composite Structures ◽  
Shear Thickening ◽  
Impact Studies ◽  
Shear Thickening Fluids

Experimental and numerical analysis of the sound insulation property of wood plastic composites (WPCs) filled with precipitated CaCO3

Holzforschung ◽  
2013 ◽  
Vol 67 (3) ◽  
pp. 301-306 ◽  
Author(s):  
Peng Li ◽  
Birm-June Kim ◽  
Qingwen Wang ◽  
Qinglin Wu
Keyword(s):  
Numerical Analysis ◽  
Transmission Loss ◽  
Weight Ratio ◽  
Physical Models ◽  
Sound Insulation ◽  
Insulation Property ◽  
Sound Scattering ◽  
Precipitated Calcium Carbonate ◽  
Plastic Composite ◽  
Mass Increase

Abstract The sound transmission loss (STL) of precipitated calcium carbonate (PCC)-filled wood plastic composite (WPC) was studied using a numerical analysis method based on the mass law and sound scattering theory. Several physical models for explaining sound wave transmission in WPC were established, and relevant STL equations were derived. The STL of WPC filled with different PCC weight ratios was analyzed using these models. The results showed that the STL of WPC increased with an increase in sound frequency and PCC weight ratio. The improvement of sound insulation was attributed to the mass increase, sound scattering enhancement by the fillers, and PCC weight ratio. The predicted results showed similar trends to the experimental data under the same processing conditions. It was concluded that the proposed models can be used to analyze the STL of filled WPC. Larger inorganic particle size led to higher STL, but its effect was not obvious at lower frequency ranges. Predicted STL increased with increased weight ratio of wood for the whole frequency range tested.

Effect of Alumina Addition on the Rheological Behavior of Shear Thickening Fluids

2019 ◽  
Vol 798 ◽  
pp. 331-336
Author(s):  
Natnicha Nuampakdee ◽  
Sujarinee Sinchai ◽  
Chaiwut Gamonpilas
Keyword(s):  
Rheological Behavior ◽  
Colloidal Particles ◽  
Volume Fraction ◽  
Shear Thickening ◽  
Body Armor ◽  
Shear Stresses ◽  
Hard Material ◽  
Shear Rates ◽  
Shear Thickening Fluids ◽  
Alumina Addition

Shear thickening fluids (STF) have attracted much attention in many applications including body armor. In this study, suspensions of silica colloidal particles and polyethylene glycol fluid were prepared at varying volume fractions φ = 0.3 to 0.52 and their rheological behavior was investigated. It was found that the suspensions exhibited a Newtonian behavior for φ < 0.4, whilst a shear thinning followed by a thickening behavior could clearly be observed for φ > 0.4. Furthermore, the critical shear rates for the onset of shear thickening was found to decrease with increasing silica volume fraction but the corresponding critical shear stresses were independent of the volume fraction. To improve the ballistic protective performance, small amount of hard material particles, such as alumina, were added into the silica suspension of φ = 0.5. It was shown that the critical shear rates of the reinforced-STFs decreased with increasing volume fraction and decreasing alumina particle size. However, higher thickening ratio was observed for the alumina additive with agglomerated structure and this ratio increased with increasing alumina volume fraction.

Application Research Development of Smart Materials on Personnel Armor Protective Materials

2014 ◽  
Vol 1004-1005 ◽  
pp. 1396-1400
Author(s):  
Jun Liu ◽  
Dang Sheng Xiong ◽  
Bin Li
Keyword(s):  
Chemical Reaction ◽  
Smart Materials ◽  
Shear Thickening ◽  
Research Development ◽  
Application Research ◽  
Shear Thickening Fluids ◽  
Magneto Rheological ◽  
Protective Performance

Integration of smart materials such as field-responsive fluid, i.e. Electro-rheological (ER) , magneto-rheological (MR) and shear thickening fluids (STFs), into armor protective materials, may probably solve the problem between its portability and protective performance. The wide applications of three fluids are described in brief in this paper, and research developments (especially STFs’ in detail) of armor protective materials strengthened by utilizing three fluids or chemical reaction material are summarized. Analysises are made of the questions faced by these composites researches. The foreground is talked about in the end.

Research and Applications of Shear Thickening Fluids

2011 ◽  
Vol 4 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Jie Ding ◽  
Weihua Li ◽  
Shirley Z. Shen
Keyword(s):  
Shear Thickening ◽  
Shear Thickening Fluids

Dynamic compressive response of 3D GFRP composites with shear thickening fluid (STF) matrix as cushioning materials

2021 ◽  
pp. 002199832098424
Author(s):  
Mohsen Jeddi ◽  
Mojtaba Yazdani
Keyword(s):  
Shear Thickening ◽  
Low Velocity Impact ◽  
Gfrp Composites ◽  
High Concentration ◽  
Low Velocity ◽  
Shear Thickening Fluid ◽  
Compressive Response ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Shear Thickening Fluids

Whereas most previous studies have focused on improving the penetration resistance of Shear Thickening Fluids (STFs) treated composites, in this study, the dynamic compressive response of single and multi-ply 3 D E-Glass Fiber Reinforced Polymer (GFRP) composites with the STF matrix was investigated by using a drop-weight low-velocity impact test. The experimental results revealed the STF improved the compressive and cushioning performance of the composites such that with increasing its concentration, further improvement was observed. The five-ply composite containing the STF of 30 wt% silica nanoparticles and 1 wt% carbon nanotubes (CNTs) reduced the applied peak force by 56% and 26% compared to a steel plate and five-ply neat samples, respectively. A series of repeated impacts was performed, and it was found that the performance of high-concentration composites is further decreased under this type of loading.

scholarly journals High Performance NbMoTa–Al2O3 Multilayer Composite Structure Manufacturing by Laser Directed Energy Deposition

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1685
Author(s):  
Hang Zhang ◽  
Zihao Chen ◽  
Yaoyao He ◽  
Xin Guo ◽  
Qingyu Li ◽  
...  
Keyword(s):  
Smart Materials ◽  
Composite Structure ◽  
Composite Structures ◽  
High Performance ◽  
Energy Deposition ◽  
Coefficient Of Thermal Expansion ◽  
Multilayer Composite ◽  
Forming Process ◽  
Directed Energy Deposition ◽  
Directed Energy

The conventional method of preparing metal–ceramic composite structures causes delamination and cracking defects due to differences in the composite structures’ properties, such as the coefficient of thermal expansion between metal and ceramic materials. Laser-directed energy deposition (LDED) technology has a unique advantage in that the composition of the materials can be changed during the forming process. This technique can overcome existing problems by forming composite structures. In this study, a multilayer composite structure was prepared using LDED technology, and different materials were deposited with their own appropriate process parameters. A layer of Al2O3 ceramic was deposited first, and then three layers of a NbMoTa multi-principal element alloy (MPEA) were deposited as a single composite structural unit. A specimen of the NbMoTa–Al2O3 multilayer composite structure, composed of multiple composite structural units, was formed on the upper surface of a φ20 mm × 60 mm cylinder. The wear resistance was improved by 55% compared to the NbMoTa. The resistivity was 1.55 × 10−5 Ω × m in the parallel forming direction and 1.29 × 10−7 Ω × m in the vertical forming direction. A new, electrically anisotropic material was successfully obtained, and this study provides experimental methods and data for the preparation of smart materials and new sensors.

scholarly journals Analysis of the transmission loss of double-leaf panels with an equivalent spring–mass model for studs

2020 ◽  
Vol 37 ◽  
pp. 126-133
Author(s):  
Yuan-Wei Li ◽  
Chao-Nan Wang
Keyword(s):  
Distribution Curve ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Experimental Results ◽  
Sound Insulation ◽  
Sound Transmission Loss ◽  
Mass Model ◽  
Steel Stud ◽  
Panel Thickness ◽  
Stiffness Distribution

Abstract The purpose of this study was to investigate the sound insulation of double-leaf panels. In practice, double-leaf panels require a stud between two surface panels. To simplify the analysis, a stud was modeled as a spring and mass. Studies have indicated that the stiffness of the equivalent spring is not a constant and varies with the frequency of sound. Therefore, a frequency-dependent stiffness curve was used to model the effect of the stud to analyze the sound insulation of a double-leaf panel. First, the sound transmission loss of a panel reported by Halliwell was used to fit the results of this study to determine the stiffness of the distribution curve. With this stiffness distribution of steel stud, some previous proposed panels are also analyzed and are compared to the experimental results in the literature. The agreement is good. Finally, the effects of parameters, such as the thickness and density of the panel, thickness of the stud and spacing of the stud, on the sound insulation of double-leaf panels were analyzed.

Sign in / Sign up

Export Citation Format

Share Document