Mechanical Properties of a Ceramic Coating With VEM Infiltration

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Peter J. Torvik ◽  
Jason Hansel
Keyword(s):  
Mechanical Properties ◽  
Storage Modulus ◽  
Viscoelastic Material ◽  
Material Properties ◽  
Elevated Temperatures ◽  
Loss Modulus ◽  
Strong Dependence ◽  
Cyclic Strain ◽  
Air Plasma ◽  
Infiltration Tests

In order to determine the mechanical properties of materials suitable for use as coatings on structural or gas turbine components, it is often necessary to conduct testing on coated specimens, with the properties of the coating then to be extracted from the response. A methodology for extracting material properties from comparisons of resonant frequencies and system loss factors for coated and uncoated beams, which is applicable even when the desired properties (storage and loss modulus) have a strong dependence on the amplitude of cyclic strain, is summarized and applied to the determination of the material properties of an air plasma sprayed alumina-titania blend ceramic to which a viscoelastic material has been added by vacuum infiltration. Tests were conducted at both room and elevated temperatures. Material properties obtained from specimens with three coating thicknesses are compared and show that values obtained for the stiffness (storage modulus) decrease with increasing coating thickness, but that values obtained for the measure of dissipative capacity (loss modulus) are essentially independent of thickness. Addition of the infiltrate was found to double the storage modulus and to increase the loss modulus at room temperature by factors of up to 3, depending on the amplitude of cyclic strain. The storage modulus of this infiltrated coating appears to diminish with increasing depth into the coating, suggesting dependence on the amount of infiltrate present. The loss modulus, however, appears to be comparatively insensitive to the amount of infiltrate present. Results from a limited investigation of the influence of increased temperature on the properties of the infiltrated coating show decreases in storage modulus with temperature, and a maximum in the loss modulus at a temperature determined by the temperature dependent properties of the specific viscoelastic material used as the infiltrate.

scholarly journals Comparative dynamic mechanical properties of non-superheated and superheated A357 alloys

2017 ◽  
Author(s):  
Mazlee Mohd Noor
Keyword(s):  
Mechanical Properties ◽  
Storage Modulus ◽  
Elevated Temperatures ◽  
Loss Modulus ◽  
Optical Microscope ◽  
Dynamic Mechanical Properties ◽  
Damping Capacity ◽  
A357 Alloy ◽  
Dynamic Mechanical ◽  
Eutectic Si

The influence of superheat treatment on the microstructure and dynamic mechanical properties of A357 alloys has been investigated. The study of microstructure was performed by the optical microscope. Dynamic mechanical properties (storage modulus, loss modulus, and damping capacity) were measured by the dynamic mechanical analyzer (DMA). Microstructure showed coarser and angular eutectic Si particles with larger α-Al dendrites in the non-superheated A357 alloy. In contrast, finer and rounded eutectic Si particles together with smaller and preferred oriented α-Al dendrites have been observed in the superheated A357 alloy. Dynamic mechanical properties showed an increasing trend of loss modulus and damping capacity meanwhile a decreasing trend of storage modulus at elevated temperatures for superheated and non-superheated A357 alloys. The high damping capacity of superheated A357 has been ascribed to the grain boundary damping at elevated temperatures.

Properties of Mouse Cutaneous Rapidly Adapting Afferents: Relationship to Skin Viscoelasticity

2004 ◽  
Vol 92 (2) ◽  
pp. 1236-1240 ◽  
Author(s):  
P. Grigg ◽  
D. R. Robichaud ◽  
Z. Del Prete
Keyword(s):  
Viscoelastic Material ◽  
Material Properties ◽  
Viscoelastic Properties ◽  
Mechanical Response ◽  
Loss Modulus ◽  
Multiple Logistic Regression Analysis ◽  
Rate Of Change ◽  
Volterra Model ◽  
Lower Sensitivity ◽  
Dynamic Stimuli

When skin is stretched, stimuli experienced by a cutaneous mechanoreceptor neuron are transmitted to the nerve ending through the skin. In these experiments, we tested the hypothesis that the viscoelastic response of the skin influences the dynamic response of cutaneous rapidly adapting (RA) neurons. Cutaneous RA afferent neurons were recorded in 3 species of mice (Tsk, Pallid, and C57BL6) whose skin has different viscoelastic properties. Isolated samples of skin and nerve were stimulated mechanically with a dynamic stretch stimulus, which followed a pseudo Gaussian waveform with a bandwidth of 0–60 Hz. The mechanical response of the skin was measured as were responses of single RA cutaneous mechanoreceptor neurons. For each neuron, the strength of association between spike responses and the dynamic and static components of stimuli were determined with multiple logistic regression analysis. The viscoelastic material properties of each skin sample were determined indirectly, by creating a nonlinear (Wiener–Volterra) model of the stress–strain relationship, and using the model to predict the complex compliance (i.e., the viscoelastic material properties). The dynamic sensitivity of RA mechanoreceptor neurons in mouse hairy skin was weakly related to the viscoelastic properties of the skin. Loss modulus and phase angle were lower (indicating a decreased viscous component of response) in Tsk and Pallid than in C57BL6 mice. However, RA mechanoreceptor neurons in Tsk and Pallid skin did not differ from those in C57 skin with regard to their sensitivity to the rate of change of stress or to the rate of change of incremental strain energy. They did have a decreased sensitivity to the rate of change of tensile strain. Thus the skin samples with lower dynamic mechanical response contained neurons with a somewhat lower sensitivity to dynamic stimuli.

The Irradiation Crosslinking of Poly(vinylidene fluoride-​chlorotrifluoroethylene)

2014 ◽  
Vol 716-717 ◽  
pp. 7-10
Author(s):  
Jian Chen
Keyword(s):  
Mechanical Properties ◽  
Storage Modulus ◽  
Ultraviolet Irradiation ◽  
Vinylidene Fluoride ◽  
Loss Modulus ◽  
Great Influence ◽  
Poly Vinylidene Fluoride ◽  
Content Support

Vinylidenefluoride (VDF) and chlorotrifluoroethylene (CTFE) copolymers were crosslinked by ultraviolet irradiation, chlorotrifluoroethylene content has a great influence on the crosslinked copolymers, high CTFE content support more joint pots, the properties of the copolymer shows higher storage modulus, the loss modulus gets smaller. The copolymer mechanical properties gets much higher.

scholarly journals Mechanical Properties of Steels for Cold-Formed Steel Structures at Elevated Temperatures

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Zhen Nie ◽  
Yuanqi Li ◽  
Yehua Wang
Keyword(s):  
Mechanical Properties ◽  
Material Properties ◽  
Elevated Temperatures ◽  
Elasticity Modulus ◽  
Mechanical Performance ◽  
Strain Curve ◽  
Steel Structures ◽  
Test Method ◽  
Stress Relieving ◽  
Cold Formed Steel

It is highly important to clarify the high-temperature mechanical properties in the design of cold-formed steel (CFS) structures under fire conditions due to the unique deterioration feature in material properties under fire environment and associated reduction to the mechanical performance of members. This paper presents the mechanical properties of widely used steels for cold-formed steel structures at elevated temperatures. The coupons were extracted from original coils of proposed full annealed steels (S350 and S420, with nominal yielding strengths 280 MPa and 350 MPa) and proposed stress relieving annealed steels (G500, with nominal yielding strength 500 MPa) for CFS structures with thickness of 1.0 mm and 1.2 mm, and a total of nearly 50 tensile tests were carried out by steady-state test method for temperatures ranging from 20 to 700°C. Based on the tests, material properties including the yield strengths, ultimate strengths, the elasticity modulus, and the stress-strain curve were obtained. Meanwhile, the ductility of steels for CFS structures was discussed. Then, the temperature-dependent retention factors of yield strengths and elasticity modulus were compared to those provided by design codes and former researchers. Finally, a set of prediction equations of the mechanical properties for steels for CFS structures at elevated temperatures was proposed depending on existing tests data.

Viscoelastic Material Properties of SU-8 and Carbon-Nanotube-Reinforced SU-8 Materials

2006 ◽  
Author(s):  
Seungbae Park ◽  
Soonwan Chung ◽  
Harold Ackler ◽  
Sandeep Makhar
Keyword(s):  
Carbon Nanotube ◽  
Strain Rate ◽  
Viscoelastic Material ◽  
Material Properties ◽  
Elevated Temperatures ◽  
Mechanical Reliability ◽  
Creep Stress ◽  
Post Exposure Bake ◽  
Carbon Nano Tube ◽  
Composite Carbon

The viscoelastic material properties of SU-8 and carbon nanotube-reinforced SU-8 composite material are characterized by tensile testing. Dogbone samples of 0.1mm thickness are prepared by micro-fabrication process, which is composed of spin coat, soft bake, expose, and post exposure bake. To fabricate CNT polymer composite, carbon nano-tube of 0.2wt% is mixed with SU-8. To observe the effect of applied strain rate and temperature on Young's modulus and Poisson's ratio, strain rate is varied from 5×10-5 to 2.5×10-4 (/sec) at elevated temperatures in the range of 25 to 200°C. Since the viscoelastic material properties are important in polymer, creep, stress relaxation and dynamic mechanical analyses are performed at elevated temperatures. The viscoelastic material properties of SU-8 and CNT-reinforced SU-8 composite are compared, and the mechanical reliability of these polymers in MEMS applications is discussed.

scholarly journals Effect of Ultraviolet-A (UV-A) and Ultraviolet-C (UV-C) Light on Mechanical Properties of Oyster Mushrooms during Growth

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Tindibale L. Edward ◽  
M. S. K. Kirui ◽  
Josiah O. Omolo ◽  
Richard G. Ngumbu ◽  
Peter M. Odhiambo
Keyword(s):  
Mechanical Properties ◽  
Storage Modulus ◽  
Loss Factor ◽  
Loss Modulus ◽  
Control Sample ◽  
Ultraviolet A ◽  
Significant Difference ◽  
Ultraviolet C ◽  
Oyster Mushrooms ◽  
Uv C

This study investigated the effects of ultraviolet-A (UV-A) and ultraviolet-C (UV-C) light on the mechanical properties in oyster mushrooms during the growth. Experiments were carried out with irradiation of the mushrooms with UV-A (365 nm) and UV-C (254 nm) light during growth. The exposure time ranged from 10 minutes to 60 minutes at intervals of 10 minutes and irradiation was done for three days. The samples for experimental studies were cut into cylindrical shapes of diameter 12.50 mm and thickness 3.00 mm. The storage modulus, loss modulus, and loss factor of the irradiated samples and control samples were determined for both UV bands and there was a significant difference between the storage modulus, loss modulus, and loss factor of the irradiated samples by both UV bands with reference to the control sample, P<0.05. UV-C light irradiated samples had higher loss modulus and loss factor but low storage modulus as temperature increased from 35 to 100°C with respect to the control sample while UV-A light irradiated samples had lower loss modulus, low loss factor, and higher storage modulus than UV-C irradiated samples.

REACTIVE COMPATIBILIZATION OF THE BLENDS OF THERMOPLASTIC POLYURETHANE AND POLYDIMETHYLSILOXANE RUBBER

2015 ◽  
Vol 88 (4) ◽  
pp. 584-603 ◽  
Author(s):  
Jineesh Ayippadath Gopi ◽  
Golok Bihari Nando
Keyword(s):  
Mechanical Properties ◽  
Storage Modulus ◽  
Loss Modulus ◽  
Thermoplastic Polyurethane ◽  
Domain Size ◽  
Damping Factor ◽  
Creep Tests ◽  
Dynamic Mechanical ◽  
Compatibilization Effect ◽  
Compatibilized Blends

ABSTRACT The effect of ethylene-co-methacrylate (EMA) as polymeric chemical compatibilizer on the mechanical, dynamic mechanical, phase morphology, adhesion, and rheological properties of the blends of thermoplastic polyurethane (TPU)–polydimethylsiloxane rubber (PDMS) was investigated at different blend ratios. Melt blending technique was used to prepare the compatibilized blends. Enhancement of the mechanical properties and the reduction of dispersed PDMS domain size in the alloy confirmed the compatibilization effect of EMA on TPU-PDMS blends. Dynamic mechanical properties such as storage modulus, loss modulus, and the damping factor were evaluated to assess the compatibilization effect of EMA on TPU-PDMS blends. Creep tests revealed that compatibilization led to better dimensional stability. Compatibilized blends with finer PDMS rubber domains showed relatively less reduction in storage modulus as compared with uncompatibilized blends during stress relaxation studies. Rheological analysis suggested that the incorporation of EMA decreased the interfacial slip between the blend constituents, and this also confirmed the compatibilization effect of EMA on TPU-PDMS rubber blends as a polymeric reactive compatibilizer.

Study on Dynamic Mechanical Properties of n-HA/PA66 Composites

2011 ◽  
Vol 418-420 ◽  
pp. 1511-1515
Author(s):  
Lin Cheng ◽  
Xiang Zhang ◽  
Yu Bao Li
Keyword(s):  
Mechanical Properties ◽  
Storage Modulus ◽  
Loss Modulus ◽  
Physiological Saline ◽  
Dynamic Mechanical Properties ◽  
Intrinsic Properties ◽  
Polyamide 66 ◽  
Dynamic Mechanical ◽  
Reinforcing Effects

The dynamic mechanical properties of nano-hydroxyapatite (n-HA) reinforced polyamide 66 (PA66) biocomposites were studied with reference to the effect of n-HA content, frequency and physiological saline. The intrinsic properties of the components, morphology of the system and the nature of interface between the phases determine the dynamic mechanical properties of the composite. The storage modulus (E') values of n-HA/PA66 composites were much higher than those of pure PA66, indicating that the incorporation of n-HA in PA66 matrix induced reinforcing effects obviously. And the E' values of composites increased with increasing of n-HA content. The loss modulus (E") of the composite with 30wt% n-HA was higher that those of pure PA66 and the composite with 40wt% n-HA below 55°C, however, above 55°C, the E" values enhanced with increase of n-HA content. Both frequency and physiological saline had obvious effects on the dynamic mechanical properties for n-HA/PA66 composite. E' and E" values enhanced with increase of frequency, but tanδ values decreased with increasing of frequency. After soaked in physiological saline, the E' and E" values of the composite decreased.

scholarly journals Dynamic mechanical analysis of nylon 6 fiber-reinforced acrylonitrile butadiene rubber composites

2021 ◽  
pp. 096739112110461
Author(s):  
C Rajesh ◽  
P Divia ◽  
S Dinooplal ◽  
G Unnikrishnan ◽  
E Purushothaman
Keyword(s):  
Mechanical Properties ◽  
Storage Modulus ◽  
Loss Modulus ◽  
Dynamic Mechanical Properties ◽  
Damping Factor ◽  
Butadiene Rubber ◽  
Bonding Agents ◽  
Fiber Loading ◽  
Dynamic Mechanical ◽  
Acrylonitrile Butadiene Rubber

Dynamic mechanical properties of polymeric materials are of direct relevance to a range of unique polymer applications. The aim of the study is to investigate the dynamic mechanical properties of composites of short nylon 6 fiber with acrylonitrile butadiene rubber (NBR). The storage modulus (G′), loss modulus (G″), and the damping factor (tan δ) have been analyzed with reference to the effects of fiber loading, curing systems, and bonding agents over a range of temperature and at varying frequencies. The storage modulus increases with increment in fiber loading, whereas loss modulus and damping factor decrease. The glass transition temperature shifts to higher temperature upon increment in fiber loading. Dicumyl peroxide (DCP)–cured composites show higher storage modulus and lower damping than the corresponding sulfur-cured one. The addition of hexa-resorcinol and phthalic anhydride as bonding agents enhances the dynamic mechanical properties of the composites. The experimental results have been evaluated by comparing with Einstein, Guth, and Nielsen models.

Dynamic mechanical behavior of composite materials reinforced by graphene and huntite minerals

2021 ◽  
Vol 63 (12) ◽  
pp. 1090-1096
Author(s):  
Dilek Atilla ◽  
Binnur Gören
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Storage Modulus ◽  
Loss Modulus ◽  
Damping Ratio ◽  
Weight Percent ◽  
Dynamic Mechanical Properties ◽  
Grain Structure ◽  
Dynamic Mechanical ◽  
Pure Resin

Abstract The aim of this study is to investigate the dynamic mechanical properties of composite materials reinforced by mineral experimentally. Graphene and huntite minerals were added to epoxy resin at different weight ratios (wt.-%) as 0.5 weight percent, 1 weight percent and 3 weight percent, to examine the effect of mineral types and percentages on the resulting dynamic mechanical properties. In addition, the effect of non-layered huntite unlike graphene, with a nano-sized grain structure, was investigated. Thus, glass transition temperature (Tg), storage modulus (E’), loss modulus (E”) and damping ratio (tan δ) values were determined and compared. Moreover, a tensile test was performed in order to explain the relation between stress and strain. It was seen that adding different minerals caused different results according to types and proportions. In general, adding minerals to the pure resin increased the storage modulus and loss modulus, whereas the damping ratio (tan δ) decreased compared to the pure resin.

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