The In-Situ Measurement of Biaxial Modulus and Residual Stress of Multi-Layer Polymeric Thin Films

1990 ◽  
Vol 188 ◽  
Author(s):  
Pinyen Lin ◽  
Stephen D. Senturia
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Integrated Circuits ◽  
Measurement Techniques ◽  
Mechanical Analysis ◽  
Polymeric Coatings ◽  
Properties Of Coatings ◽  
Polymeric Thin Films ◽  
Layer Structures

Polymeric coatings have been used in many ways from automobile paints to package coatings for integrated circuits. It is important to understand the mechanical properties of coatings in order to ensure fulfilling their designed functions. To measure these properties, in situ measurement techniques are desirable since these techniques measure the mechanical properties of coatings in the presence of the correct residual stress. In addition, the coatings most commonly used are multi-layer structures, a fact which increases the difficulty of the mechanical analysis. At present, the in situ mechanical behavior of multi-layer coatings has not been well characterized, and very few researchers have reported a satisfactory way to analyze multi-layer problems.

Numerical Analysis of Weld Residual Stress in a Pressurizer Surge Nozzle Full-Scale Mockup: The Effect of Hardening Constitutive Model and Interpass Temperature

2015 ◽  
Author(s):  
Minh N. Tran ◽  
Ondrej Muránsky ◽  
Michael R. Hill ◽  
Mitchell D. Olson
Keyword(s):  
Thermal Analysis ◽  
Residual Stress ◽  
Kinematic Hardening ◽  
Measurement Techniques ◽  
Mechanical Analysis ◽  
Full Scale ◽  
Contour Method ◽  
Cooperative Research ◽  
Weld Residual Stress ◽  
Interpass Temperature

In an effort to shed light on accuracy and reliability of finite element (FE) weld modeling outputs, the U.S. Nuclear Regulatory Commission (NRC) and the Electric Power Research Institute (EPRI) have been engaged in a program of cooperative research on weld residual stress (WRS) prediction. The current work presents numerical FE simulation of the WRS in a pressurizer surge nozzle full-scale mockup (Phase 2b), as a part of the broader NRC/EPRI program. Sequentially-coupled, thermo-mechanical FE analysis was performed, whereby the numerical solution from the thermal analysis was used as an input in the mechanical analysis. The thermal analysis made use of a dedicated weld modeling tool to accurately calibrate an ellipsoidal Gaussian volumetric heat source. The subsequent mechanical analysis utilized the isotropic and nonlinear kinematic hardening constitutive models to capture cyclic response of the material upon welding. The modeling results were then validated using a number of measurement techniques (deep hole drilling, contour method, slitting, and biaxial mapping). In addition, an effect of the interpass temperature (i.e. 24.5 °C, 150 °C, and 260 °C) on the final prediction of WRS is discussed.

scholarly journals Melanocyte pigmentation stiffens murine cardiac tricuspid valve leaflet

2009 ◽  
Vol 6 (40) ◽  
pp. 1097-1102 ◽  
Author(s):  
Kantesh Balani ◽  
Flavia C. Brito ◽  
Lidia Kos ◽  
Arvind Agarwal
Keyword(s):  
Mechanical Properties ◽  
Storage Modulus ◽  
Tricuspid Valve ◽  
Viscoelastic Properties ◽  
Mechanical Analysis ◽  
Current Work ◽  
Valve Leaflet ◽  
Stiffness Measurement ◽  
Proper Functioning

Pigmentation of murine cardiac tricuspid valve leaflet is associated with melanocyte concentration, which affects its stiffness. Owing to its biological and viscoelastic nature, estimation of the in situ stiffness measurement becomes a challenging task. Therefore, quasi-static and nanodynamic mechanical analysis of the leaflets of the mouse tricuspid valve is performed in the current work. The mechanical properties along the leaflet vary with the degree of pigmentation. Pigmented regions of the valve leaflet that contain melanocytes displayed higher storage modulus (7–10 GPa) than non-pigmented areas (2.5–4 GPa). These results suggest that the presence of melanocytes affects the viscoelastic properties of the mouse atrioventricular valves and are important for their proper functioning in the organism.

Comparison of two encapsulation systems of UV stabilizers on the UV protection efficiency of wood clear coats

2018 ◽  
Vol 39 (1) ◽  
pp. 94-103
Author(s):  
Caroline Queant ◽  
Pierre Blanchet ◽  
Véronic Landry ◽  
Diane Schorr
Keyword(s):  
Mechanical Properties ◽  
Color Change ◽  
Mechanical Analysis ◽  
Accelerated Weathering ◽  
Properties Of Coatings ◽  
Protection Efficiency ◽  
Responsive Polymers ◽  
Ultraviolet Absorbers ◽  
Coating Formulation ◽  
Hindered Amine Light Stabilizers

Abstract One of the major issues in the wood industry is the durability of clear coatings. The addition of organic ultraviolet absorbers (UVAs) improves coating resistance by the absorption and conversion of UV radiation into harmless heat. Organic UVAs are, however, easily degraded by free radicals produced by photodegradation inside the polymer matrix and are prone to migration in the coating. In this study, commercial UVAs and hindered amine light stabilizers (HALS) entrapped into poly(methyl methacrylate) (PMMA) microspheres and CaCO3 templates coated with UV-responsive polymers were added into clear acrylic water-based coating formulation. Artificial accelerated weathering experiments were performed on each formulation. Raman spectroscopy mapping was performed to visualize the concentration and distribution of UVAs and HALS. This study also presents a comparison of the mechanical properties of coatings obtained by dynamic mechanical analysis. Results showed that coating mechanical properties were improved when using encapsulated UVAs and HALS inside PMMA microspheres. The color change of the wood and coating system was minimized and the production of photo-oxidation compounds in the binder was also limited.

scholarly journals Combined Calorimetry, Thermo-Mechanical Analysis and Tensile Test on Welded EN AW-6082 Joints

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1396 ◽  
Author(s):  
Philipp Wiechmann ◽  
Hannes Panwitt ◽  
Horst Heyer ◽  
Michael Reich ◽  
Manuela Sander ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Welded Joints ◽  
Thermal Analyses ◽  
Mechanical Analysis ◽  
Image Correlation ◽  
Ex Situ ◽  
Compression Tests ◽  
Depth Analysis ◽  
Welding Processes

Wide softening zones are typical for welded joints of age hardened aluminium alloys. In this study, the microstructure evolution and distribution of mechanical properties resulting from welding processes of the aluminium alloy EN AW-6082 (AlSi1MgMn) was analysed by both in-situ and ex-situ investigations. The in-situ thermal analyses included differential scanning calorimetry (DSC), which was used to characterise the dissolution and precipitation behaviour in the heat affected zone (HAZ) of welded joints. Thermo-mechanical analysis (TMA) by means of compression tests was used to determine the mechanical properties of various states of the microstructure after the welding heat input. The necessary temperature–time courses in the HAZ for these methods were measured using thermocouples during welding. Additionally, ex-situ tensile tests were done both on specimens from the fusion zone and on welded joints, and their in-depth analysis with digital image correlation (DIC) accompanied by finite element simulations serve for the description of flow curves in different areas of the weld. The combination of these methods and the discussion of their results make an essential contribution to understand the influence of welding heat on the material properties, particularly on the softening behaviour. Furthermore, the distributed strength characteristic of the welded connections is required for an applicable estimation of the load-bearing capacity of welded aluminium structures by numerical methods.

Synthesis and Properties Epoxy Resin/Mesoporous Silica-Sepiolite Nanocomposites

2010 ◽  
Vol 129-131 ◽  
pp. 1248-1251 ◽  
Author(s):  
Qing Ming Jia ◽  
Shao Yun Shan ◽  
Li Hong Jiang ◽  
Ya Ming Wang
Keyword(s):  
Mechanical Properties ◽  
Mesoporous Silica ◽  
Epoxy Resin ◽  
Mechanical Analysis ◽  
Test Results ◽  
Time Dynamic ◽  
In Situ Deposition ◽  
Ep Matrix ◽  
And Storage

Size, shape and processing of the inorganic fillers are important for improving properties of nanocomposites. In this paper, a novel nanofiller containing mesoporous silica(MS) and fibrous sepiolite(SE) was prepared by in situ deposition method. EP/MS-SE nanocomposite was obtained by adding MS-SE to epoxy resin(EP) matrix. Morphologies and mechanical properties of the new ternary nanocomposite were investigated. For purpose of comparison, the corresponding binary nanocomposites, i.e., EP modified with either MS or SE, were tested as well. The test results of mechanical properties show that MS improves the strength of EP and SE obviously enhances the toughness of EP, but oM-MS exhibits synergistic effect on toughening and reinforcing of EP at the same time. Dynamic mechanical analysis revealed that the glass transition temperature and storage modulus of the EP/MS-SE nanocomposite was higher than those of pure EP.

Residual Stress and Wear Characteristics of Ni3Al Coating Layer

2005 ◽  
Vol 490-491 ◽  
pp. 619-624
Author(s):  
Takayuki Murotani ◽  
Zhou Wang ◽  
Akira Ikenaga ◽  
Yukio Hirose
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Intermetallic Compound ◽  
Residual Stresses ◽  
Coating Layer ◽  
Measurement Techniques ◽  
Material Strength ◽  
Wear Characteristics ◽  
Ni3al Intermetallic Compound ◽  
Ni3al Intermetallic

The Ni3Al intermetallic compound is of great interest because of its oxidation, corrosion-resistance, and high melting point. The low-temperature hot press + thermal diffusion process method is a technique that uses the thermal reactive diffusions between the elements that compose the intermetallic compound. In this method the powder mixture is heated and be able to generate the diffusions of the powder elements by keeping the heating temperature comparatively lower temperature with other technique. The authors evaluated the preparation conditions and joining quality in Ni3Al coating layer of particular interest is the residual stress due to the different mechanical properties of the coating and the substrate and its effect on the interface joining quality. It is known that residual stresses were generated by the difference in the coefficient of thermal expansion (CTE) of coating and substrate during cooling process. Such a residual stress caused by the differences of mechanical properties has strong influence on composite material strength. X-ray stress measurement techniques has been developed for experimental determination of residual stresses. In this paper, the Ni3Al intermetallic compound was coated on spheroidal graphite cast iron and austenite stainless steel using the reactive sintering method. Wear characteristics and residual stress on these intermetallic compound layers were investigated to evaluate the effect of substrate materials on coating layer properties.

scholarly journals Polydopamine-Modified Al2O3/Polyurethane Composites with Largely Improved Thermal and Mechanical Properties

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1772 ◽  
Author(s):  
Ruikui Du ◽  
Li He ◽  
Peng Li ◽  
Guizhe Zhao
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
In Situ Polymerization ◽  
Mechanical Analysis ◽  
Thermal Interface Materials ◽  
Sem Images ◽  
Elongation At Break ◽  
Polyurethane Composites ◽  
Interface Materials

Alumina/polyurethane composites were prepared via in situ polymerization and used as thermal interface materials (TIMs). The surface of alumina particles was modified using polydopamine (PDA) and then evaluated via Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG), and Raman spectroscopy (Raman). Scanning electron microscope (SEM) images showed that PDA-Al2O3 has better dispersion in a polyurethane (PU) matrix than Al2O3. Compared with pure PU, the 30 wt% PDA-Al2O3/PU had 95% more Young’s modulus, 128% more tensile strength, and 76% more elongation at break than the pure PU. Dynamic mechanical analysis (DMA) results showed that the storage modulus of the 30 wt% PDA-Al2O3/PU composite improved, and the glass transition temperature (Tg) shifted to higher temperatures. The thermal conductivity of the 30 wt% PDA-Al2O3/PU composite increased by 138%. Therefore, the results showed that the prepared PDA-coated alumina can simultaneously improve both the mechanical properties and thermal conductivity of PU.

Synthesis-Morphology-Mechanical Properties Relationships Of Polymer-Silica Nanocomposite Hybrid Materials

1999 ◽  
Vol 576 ◽  
Author(s):  
P. Hajji ◽  
L. David ◽  
J. F. Gerard ◽  
H. Kaddami ◽  
J. P. Pascault ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Sol Gel ◽  
Mechanical Analysis ◽  
Resonance Spectroscopy ◽  
Silica Nanocomposites ◽  
X Ray Scattering ◽  
Transmission Electron

ABSTRACTTwo types of polymer-silica nanocomposites have been prepared by undergoing free radical polymerization of 2-hydroxyethyl methacrylate (HEMA) either in the presence of HEMA-functionalized SiO2 nanoparticles (Type 1) or during the simultaneous in situ growing of the silica phase through the acid-catalyzed sol-gel polymerization of tetraethoxysilane (TEOS) (Type 2). Relationships between synthesis, morphology and mechanical properties are discussed mainly on the basis of solid state 29Si nuclear magnetic resonance spectroscopy (NMR), transmission electron microscopy (TEM), small angle X-ray scattering (SAXS), and dynamic mechanical analysis (DMA).

Quantitative and nondestructive determination of residual stress for SiO2 thin film by laser-generated surface acoustic wave technique

2021 ◽  
Author(s):  
Li Zhang ◽  
Xia Xiao ◽  
Haiyang Qi ◽  
Yiting Huang ◽  
Huiquan Qin
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Residual Stress ◽  
Integrated Circuits ◽  
Acoustic Wave ◽  
Dispersion Curve ◽  
Surface Acoustic Wave ◽  
Physical And Mechanical Properties ◽  
Sio2 Film ◽  
Sio2 Films

Abstract The laser-generated surface acoustic wave (SAW) technique is a promising method to measure the mechanical properties of thin films quickly and nondestructively. Residual stress is inevitable during the processing and manufacturing of integrated circuits, which will have a major impact on the physical and mechanical properties of the thin film materials and cause deterioration to the structural strength. In this study, the SAW technique based method is proposed for quantitative and nondestructive measuring the residual stress in the nanostructured films. The method is verified by the experiment measuring the SiO2 films in the thickness range of 100 to 2000 nm. The experimental procedures, including signal excitation, reception and processing, are described in detail. By matching the SAW experimental dispersion curve with the calculated theoretical dispersion curve containing the residual stress, the residual stress of the SiO2 films along [110] and [100] crystallographic orientation of the Si wafer is successfully quantified. The determination results are ranged from -65.5 to 421.1 MPa and the stress value increases as the film thickness decreases, revealing the residual stress of the SiO2 film is compressive. Meanwhile, the conventional substrate curvature method as a comparison is used to verify the correctness and feasibility of the proposed SAW method for the residual stress determination.

Densification and Mechanical Properties of B4C Based Composites Sintered by Reaction Hot-Pressing

2010 ◽  
Vol 434-435 ◽  
pp. 24-27 ◽  
Author(s):  
Guo Feng Wang ◽  
Ji Hong Zhang ◽  
Chunping Zhang ◽  
Kai Feng Zhang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Residual Stress ◽  
Thermal Properties ◽  
Sintering Temperature ◽  
Crack Deflection ◽  
Sintering Behavior ◽  
Reaction Sintering ◽  
Boron Carbide B4c

Boron carbide (B4C) possesses unique physical and thermal properties. In this paper, B4C based composites toughened by TiB2 were fabricated by in-situ reaction sintering with the original microcrystalline powders B4C, TiO2 and glucose. The influences of sintering temperature and content of TiO2 on the sintering behavior and mechanical properties were investigated. (TiB2, Al2O3)/B4C and (TiB2,SiC)/B4C composites with almost fully dense were fabricated by using additives　of Al2O3 and Si powders and sintering at 1950°C and 1900°C, the fracture toughness of composites reach to 7.09 and 6.35 MPa•m1/2 respectively. The analysis of microstructure shows that the main toughen mechanism is the crack deflection due to the existence of residual stress.

Sign in / Sign up

Export Citation Format

Share Document