Heat Built Up During Dynamic Mechanical Analysis (DMA) Testing of Rubber Specimens

2018 ◽  
Author(s):  
Roja Esmaeeli ◽  
Ashkan Nazari ◽  
Haniph Aliniagerdroudbari ◽  
Seyed Reza Hashemi ◽  
Muapper Alhadri ◽  
...  
Keyword(s):  
Dynamic Mechanical Analysis ◽  
Heat Generation ◽  
Temperature Rise ◽  
Viscoelastic Properties ◽  
Mechanical Analysis ◽  
Compression Tests ◽  
Element Analysis ◽  
Dynamic Mechanical ◽  
Fea Model ◽  
Static And Dynamic Moduli

The viscoelastic properties of rubbers play an important role in dynamic applications and are commonly measured and quantified by means of Dynamic Mechanical Analysis (DMA) tests. The rubber properties including the static and dynamic moduli are a function of temperature; and an increase in the temperature leads to a decrease in both moduli of the rubber. Due to the heat generation inside the rubber during the DMA test and the possible change of the rubber properties it is important to quantify the amount of temperature rise in the rubber specimen during the test. In this study, a Finite Element Analysis (FEA) model is used to predict the heat generation and temperature rise during the rubber DMA tests. This model is used to identify the best shape of the specimen to achieve the minimum increase in temperature during the test. The double sandwich shear test and the cyclic compression tests are considered in this study because these two tests are mostly used in industry to predict the rubber viscoelastic properties.

scholarly journals Replacement of metallic parts for polymer composite materials in motorcycle oil pumps

2016 ◽  
Vol 36 (2) ◽  
pp. 149-160 ◽  
Author(s):  
Sandro Donnini Mancini ◽  
Antídio de Oliveira Santos Neto ◽  
Maria Odila Hilário Cioffi ◽  
Eduardo Carlos Bianchi
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Glass Transition ◽  
Glass Fiber ◽  
Dynamic Mechanical Analysis ◽  
Mechanical Analysis ◽  
Neutral Medium ◽  
Element Analysis ◽  
Dynamic Mechanical ◽  
Oil Pump

A feasibility study was conducted to determine the use of polyphthalamide/glass-fiber and polyphthalamide/glass-fiber/polytetrafluoroethylene-based composites as substitutes for aluminum and steel, respectively, in the production of motorcycle oil pump parts (housing, shaft/inner gerotor and outer gerotor). New and used (80,000 km) oil pumps were subjected to performance tests, whose results indicated that the pressure and temperature of the used pump reached a maximum of 1.8 bar and 93℃, respectively. Thermogravimetric analysis indicated that the materials are stable at the maximum operating temperature, which is 20℃ lower than the minimum glass transition temperature obtained by dynamic mechanical analysis for both materials at the analyzed frequencies (defined after calculations based on rotations in neutral, medium and high gear). The pressure value was multiplied by a safety factor of at least 1.6 (i.e., 3 bar), which was used as input for a finite element analysis of the parts, as well as the elasticity modulus at glass transition temperatures obtained by dynamic mechanical analysis. The finite element analysis indicated that the von Mises stresses to which the composite parts were subjected are 7 to 50 times lower than those the materials can withstand. The results suggest that it is feasible to manufacture motorcycle oil pump parts with these composites.

The effect of yield damage on the viscoelastic properties of cortical bone tissue as measured by dynamic mechanical analysis

2007 ◽  
Vol 82A (3) ◽  
pp. 530-537 ◽  
Author(s):  
Yener N. Yeni ◽  
Richard R. Shaffer ◽  
Kevin C. Baker ◽  
X. Neil Dong ◽  
Michele J. Grimm ◽  
...  
Keyword(s):  
Dynamic Mechanical Analysis ◽  
Cortical Bone ◽  
Bone Tissue ◽  
Viscoelastic Properties ◽  
Mechanical Analysis ◽  
Dynamic Mechanical

scholarly journals Viscoelastic Properties of Contemporary Bulk-fill Restoratives: A Dynamic-mechanical Analysis

2018 ◽  
Vol 43 (3) ◽  
pp. 307-314 ◽  
Author(s):  
JEX Ong ◽  
AU Yap ◽  
JY Hong ◽  
AH Eweis ◽  
NA Yahya
Keyword(s):  
Dynamic Mechanical Analysis ◽  
Storage Modulus ◽  
Loss Tangent ◽  
Viscoelastic Properties ◽  
Loss Modulus ◽  
Artificial Saliva ◽  
Mechanical Analysis ◽  
Distilled Water ◽  
Glass Ionomer ◽  
Dynamic Mechanical

SUMMARY This study investigated the viscoelastic properties of contemporary bulk-fill restoratives in distilled water and artificial saliva using dynamic mechanical analysis. The materials evaluated included a conventional composite (Filtek Z350), two bulk-fill composites (Filtek Bulk-fill and Tetric N Ceram), a bulk-fill giomer (Beautifil-Bulk Restorative), and two novel reinforced glass ionomer cements (Zirconomer [ZR] and Equia Forte [EQ]). The glass ionomer materials were also assessed with and without resin coating (Equia Forte Coat). Test specimens 12 × 2 × 2 mm of the various materials were fabricated using customized stainless-steel molds. After light polymerization/initial set, the specimens were removed from the molds, finished, measured, and conditioned in distilled water or artificial saliva at 37°C for seven days. The materials (n=10) were then subjected to dynamic mechanical testing in flexure mode at 37°C and a frequency of 0.1 to 10 Hz. Storage modulus, loss modulus, and loss tangent data were subjected to normality testing and statistical analysis using one-way analysis of variance/Dunnett's test and t-test at a significance level of p < 0.05. Mean storage modulus ranged from 3.16 ± 0.25 to 8.98 ± 0.44 GPa, while mean loss modulus ranged from 0.24 ± 0.03 to 0.65 ± 0.12 GPa for distilled water and artificial saliva. Values for loss tangent ranged from 45.7 ± 7.33 to 134.2 ± 12.36 (10−3). Significant differences in storage/loss modulus and loss tangent were observed between the various bulk-fill restoratives and two conditioning mediums. Storage modulus was significantly improved when EQ and ZR was not coated with resin.

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