Viscoelastic Behavior of Polymer Films During Scratch Test: a Quantitative Analysis

1999 ◽  
Vol 594 ◽  
Author(s):  
Vincent D. Jardret ◽  
Warren C. Oliver
Keyword(s):  
Penetration Depth ◽  
Contact Pressure ◽  
Dynamic Properties ◽  
Abrasive Particle ◽  
Viscoelastic Behavior ◽  
Scratch Test ◽  
Dynamic Mechanical Properties ◽  
Scratch Resistance ◽  
Polymer Surfaces ◽  
Temperature History

AbstractDynamic properties of polymer surfaces affect their ability to withstand abrasive actions. Kinetic conditions, like velocity, penetration depth and shape of the abrasive particles, change the abrasion mechanisms and the morphology of the abraded surface. Using the scratch technique, along with profilometry measurement across the scratches, we have been able to completely characterize the residual scratch morphology. Pile-up deformation and visco-plastic relaxation are key phenomena that characterize the importance of ductility in the scratch resistance of polymer surfaces. Cross profilometry aids in studying the relaxation of the scratch morphology for different time and temperature history after the scratch is made. The effect of scratch velocity, penetration depth and indenter geometry on the contact pressure and friction coefficient estimated during a scratch test can also be analyzed. Following Eyring's law, a good correlation, was found between normal indentation and scratch testing in the evolution of the contact pressure with the applied strain rate. This work results in a better understanding of the stresses and the strains applied by an abrasive particle, and especially relates the dynamic mechanical properties of viscous materials, like stress exponent, to their scratch behavior. The method presented can provide for the measurement of dynamic properties of polymer surfaces or thin films under a very large range of strain rates.

Experimental and Three-Dimensional Finite Element Study of Scratch Test of Polymers at Large Deformations

2004 ◽  
Vol 126 (2) ◽  
pp. 372-379 ◽  
Author(s):  
J. L. Bucaille ◽  
E. Felder ◽  
G. Hochstetter
Keyword(s):  
Strain Hardening ◽  
Penetration Depth ◽  
Large Deformations ◽  
Numerical Study ◽  
Scratch Test ◽  
Scratch Resistance ◽  
Plastic Strains ◽  
Thermosetting Polymer ◽  
Scratch Tests ◽  
Hardening Coefficient

An experimental and numerical study of the scratch test on polymers near their surface is presented. The elastoplastic response of three polymers is compared during scratch tests at large deformations: polycarbonate, a thermosetting polymer and a sol-gel hard coating composed of a hybrid matrix (thermosetting polymer-mineral) reinforced with oxide nanoparticles. The experiments were performed using a nanoindenter with a conical diamond tip having an included angle of 30 deg and a spherical radius of 600 nm. The observations obtained revealed that thermosetting polymers have a larger elastic recovery and a higher hardness than polycarbonate. The origin of this difference in scratch resistance was investigated with numerical modelling of the scratch test in three dimensions. Starting from results obtained by Bucaille (J. Mat. Sci., 37, pp. 3999–4011, 2002) using an inverse analysis of the indentation test, the mechanical behavior of polymers is modeled with Young’s modulus for the elastic part and with the G’sell-Jonas’ law with an exponential strain hardening for the viscoplastic part. The strain hardening coefficient is the main characteristic parameter differentiating the three studied polymers. Its value is equal to 0.5, 4.5, and 35, for polycarbonate, the thermosetting polymer and the reinforced thermosetting polymer, respectively. Firstly, simulations reveals that plastic strains are higher in scratch tests than in indentation tests, and that the magnitude of the plastic strains decreases as the strain hardening increases. For scratching on polycarbonate and for a penetration depth of 0.5 μm of the indenter mentioned above, the representative strain is equal to 124%. Secondly, in agreement with experimental results, numerical modeling shows that an increase in the strain hardening coefficient reduces the penetration depth of the indenter into the material and decreases the depth of the residual groove, which means an improvement in the scratch resistance.

Temperature Dependence of Dynamic Properties of Elastomers. Relaxation Distributions

1952 ◽  
Vol 25 (4) ◽  
pp. 720-729 ◽  
Author(s):  
John D. Ferry ◽  
Edwin R. Fitzgerald ◽  
Lester D. Grandine ◽  
Malcolm L. Williams
Keyword(s):  
Distribution Function ◽  
Temperature Dependence ◽  
Dynamic Properties ◽  
Relaxation Times ◽  
Dynamic Mechanical Properties ◽  
Relaxation Processes ◽  
The Real ◽  
Reduced Frequency ◽  
Dynamic Rigidity ◽  
Composite Curve

Abstract By the use of reduced variables, the temperature dependence and frequency dependence of dynamic mechanical properties of rubberlike materials can be interrelated without any arbitrary assumptions about the functional form of either The definitions of the reduced variables are based on some simple assumptions regarding the nature of relaxation processes. The real part of the reduced dynamic rigidity, plotted against the reduced frequency, gives a single composite curve for data over wide ranges of frequency and temperature; this is true also for the imaginary part of the rigidity or the dynamic viscosity. The real and imaginary parts of the rigidity, although independent measurements, are interrelated through the distribution function of relaxation times, and this relation provides a check on experimental results. First and second approximation methods of calculating the distribution function from dynamic data are given. The use of the distribution function to predict various types of time-dependent mechanical behavior is illustrated.

scholarly journals Viscoelastic behavior of a casing material and its utilization in premium connections in high-temperature gas wells

2018 ◽  
Vol 10 (12) ◽  
pp. 168781401881745 ◽  
Author(s):  
Ying Zhang ◽  
Zhanghua Lian ◽  
Mi Zhou ◽  
Tiejun Lin
Keyword(s):  
High Temperature ◽  
Contact Pressure ◽  
Viscoelastic Model ◽  
Viscoelastic Behavior ◽  
Element Model ◽  
Gas Production ◽  
Prony Series ◽  
Gas Well ◽  
Gas Leakage ◽  
High Temperature Gas

At the high or extra-high temperatures in a natural gas oilfield, where the premium connection is employed by casing, gas leakage in the wellbore is always detected after several years of gas production. As the viscoelastic material’s mechanical properties change with time and temperature, the relaxation of the contact pressure on the connection sealing surface is the main reason for the gas leakage in the high-temperature gas well. In this article, tension-creep experiments were conducted. Furthermore, a constitutive model of the casing material was established by the Prony series method. Moreover, the Prony series’ shift factor was calculated to study the thermo-rheological behavior of the casing material ranging from 120°C to 300°C. A linear viscoelastic model was implemented in ABAQUS, and the simulation results are compared to our experimental data to validate the methodology. Finally, the viscoelastic finite element model is applied to predict the relaxation of contact pressure on the premium connections’ sealing surface versus time under different temperatures. And, the ratio of the design contact pressure and the intending gas sealing pressure is recommended for avoiding the premium connections failure in the high-temperature gas well.

scholarly journals Scratch Behaviour of Silicon Solid Solution Strengthened Ferritic Compacted Graphite Iron (CGI)

2018 ◽  
Vol 925 ◽  
pp. 318-325
Author(s):  
Rohollah Ghasemi ◽  
Anders E.W. Jarfors
Keyword(s):  
Solid Solution ◽  
Normal Load ◽  
Scratch Test ◽  
Scratch Resistance ◽  
Compacted Graphite Iron ◽  
Depth Of Penetration ◽  
Scratch Depth ◽  
Compacted Graphite ◽  
Diamond Indenter ◽  
Different Content

The present study focuses on scratch behaviour of a conventional pearlitic and a number of solid solution strengthened ferritic Compacted Graphite Iron (CGI) alloys. This was done by employing a single-pass microscratch test using a sphero-conical diamond indenter under different constant normal loads conditions. Matrix solution hardening was made by alloying with different content of Si alloy; (3.66, 4.09 and 4.59 wt%. Si) which are named as low-Si, medium-Si and high-Si ferritic CGI alloys, respectively. A good correlation between the tensile and scratch test results was observed explaining the influence of CGI’s matrix characteristics on scratch behaviour both for pearlitic and fully ferritic solution strengthened ones. Both the scratch depth and scratch width showed strong tendency to increase with increasing the normal load, however the pearlitic one showed more profound deformation compared to the solution strengthened CGI alloys. Among the investigated alloys, the maximum and minimum scratch resistance was observed for high-Si ferritic CGI and pearlitic alloys, respectively. It was confirmed by the scratched surfaces analysed using Scanning Electron Microscopy (SEM) as well. In addition, the indenter’s depth of penetration value (scratch depth) was found as a suitable measure to ascertain the scratch resistance of CGI alloys.Keywords: Silicon solution strengthening, CGI, Abrasion, Scratch testing, Scratch resistance

scholarly journals THE INFLUENCE OF SEVERAL TYPES OF RESINS ON THE DYNAMIC MECHANICAL PROPERTIES OF POLYMER MIXTURE BASED ON BUTYL RUBBER

2020 ◽  
Vol 3 (2) ◽  
pp. 36-45 ◽  
Author(s):  
O. Tarasova ◽  
Yu. Yurkin ◽  
A. Toroschin
Keyword(s):  
Phenol Formaldehyde ◽  
Dynamic Properties ◽  
Dynamic Mechanical Properties ◽  
Mechanical Analysis ◽  
Strength Properties ◽  
Butyl Rubber ◽  
Polymer Materials ◽  
Polymer Mixture ◽  
Damping Properties ◽  
Dynamic Mechanical

this work is devoted to the problem of developing vibration-damping polymer materials with high damping properties in a wide temperature range. The study of the effect of modifying additives on the strength, damping, adhesive and cohesive properties of a butyl rubber composite is the aim of this work. The task is to identify the actual temperature, frequency, dynamic and mechanical characteristics of a composite material based on butyl rubber depending on the type and concentration of resins. The key methods for studying this problem is the dynamic mechanical analysis method, aimed at obtaining information about changes in the dynamic properties of polymer materials (bond strength with metal when peeling samples of composites, determining the flow resistance of samples, determining the migration of plasticizer). Due to the established experimental dependences, it was found that the addition of resins (3% by weight) in the composition based on butyl rubber leads to an increase in the damping properties of composite materials, and an increase to (4.25% by weight) leads to their decrease. It was established that the obtained filled mixtures with a high damping peak and good adhesive and strength properties are mixtures with the addition of alkyl phenol-formaldehyde resins.

EFFECT OF ELASTOMER NANOPARTICLES ON IMPROVING THE WET SKID RESISTANCE OF SBR/NR COMPOSITES

2016 ◽  
Vol 89 (2) ◽  
pp. 262-271 ◽  
Author(s):  
Qingguo Wang ◽  
Jingrui Liu ◽  
Quande Cui ◽  
Xiao Xiao
Keyword(s):  
Dynamic Properties ◽  
Rolling Resistance ◽  
Dynamic Mechanical Properties ◽  
Fatigue Properties ◽  
Styrene Butadiene Rubber ◽  
Skid Resistance ◽  
Butadiene Rubber ◽  
Temperature Range ◽  
Styrene Butadiene ◽  
Wet Skid Resistance

ABSTRACT How to improve the wet skid resistance of rubber composites for tire tread while decreasing the rolling resistance is very important for both rubber researchers and industry. The irradiation-vulcanized elastomer particles, ultrafine fully-vulcanized powder nitrile butadiene rubber (UFPNBR), having the diameter of about 80 nm, were studied on modifying the dynamic mechanical properties of styrene butadiene rubber/natural rubber (SBR/NR) composites for tire tread. It is notable that the UFPNBR particles can improve the tanδ values of SBR/NR composites in a temperature range from −10 to 20 °C and decrease the tanδ values in the temperature range from 50 to 70 °C simultaneously, which indicates that the UFPNBR particles not only can improve the wet skid resistance but also can reduce the rolling resistance of the SBR/NR composites. On the other hand, the UFPNBR-modified SBR/NR composites also have good dynamic properties for safety operation of tires at high temperature and good tensile strength, tear strength, and fatigue properties in the range of 8 phr UFPNBR loadings.

BETTER BALANCE OF SILICA-REINFORCED NATURAL RUBBER TIRE TREAD COMPOUND PROPERTIES BY THE USE OF MONTMORILLONITE WITH OPTIMUM SURFACE MODIFIER CONTENT

2020 ◽  
pp. 000-000 ◽  
Author(s):  
Mohammad Irfan Fathurrohman ◽  
Supagorn Rugmai ◽  
Nabil Hayeemasae ◽  
Kannika Sahakaro
Keyword(s):  
Natural Rubber ◽  
Abrasion Resistance ◽  
Dynamic Properties ◽  
Rolling Resistance ◽  
Complex Viscosity ◽  
Dynamic Mechanical Properties ◽  
Rubber Matrix ◽  
Dispersing Agent ◽  
Truck Tire ◽  
Key Factor

ABSTRACT Reinforcement of silica in tire tread compounds is known to reduce hysteresis or energy loss, which leads to a production of energy-saving tires. Even though silica–silane technology has been well established, further development to enhance its performance is still needed. One of the approaches is to use hybrid or dual filler. The use of silica-organomodified montmorillonite (MMT) dual filler in the reinforcement of natural rubber (NR) truck tire tread compounds is investigated. The NR-MMT master batches were prepared by using the in situ organomodified and latex compounding method. Because the surface-modifying agent or surfactant is a key factor in determining the level of MMT dispersion in the rubber matrix, the effect of quaternary amine salt (Q) contents on mechanical and dynamic properties of NR tread compounds reinforced by silica-MMT was studied. The results revealed that MMT and Q can effectively reduce the filler–filler interaction and complex viscosity owing to a good dispersion of MMT and silica in the NR matrix and Q, which acts as a dispersing agent in addition to the silane coupling agent used in the compound, leading to improvement in tensile, abrasion resistance, and dynamic mechanical properties with an increasing amount of Q. Furthermore, at the optimum content of the surfactant used (36 wt%), the silica-MMT–reinforced NR exhibited improved tensile strength (+4%), wet grip, and rolling resistance, respectively, as indicated by loss tangent at 0 °C (+6%) and 60 °C (−15%), while maintaining a modulus at 300% strain and abrasion resistance as compared with the silica-NR reference compound. Such a dual-filler system demonstrates its potential use for tire treads with better performance.

Role of Epoxidized Natural Rubber in Dynamic Mechanical Properties of NR/ENR/silica Composites

2011 ◽  
Vol 415-417 ◽  
pp. 415-419
Author(s):  
Yue Qiong Wang ◽  
Qing Huang Wang ◽  
Yong Yue Luo ◽  
Jie Ping Zhong ◽  
Yong Zhen Li ◽  
...  
Keyword(s):  
Fatigue Test ◽  
Dynamic Properties ◽  
Dynamic Mechanical Properties ◽  
Test Results ◽  
Dynamic Mechanical ◽  
Dynamic Mechanical Thermal Analyzer ◽  
Thermal Analyzer ◽  
Self Aggregation ◽  
Temperature Dynamic

NR/ENR/silica composites with different ENR amount were prepared in an open two-roll laboratory mixing mill at room temperature. Dynamic properties of ENR filled NR/silica were performed by dynamic mechanical thermal analyzer (DMA) and compression fatigue analyzer. DMA and compression fatigue test results showed that the effect of ENR on dynamic properties of NR/silica was significant. DMA displayed the tanδ of NR/ENR/silica composites at 0 °C was increased with increasing ENR amount. Compression fatigue test indicated the presence of ENR decreased the heat produced during compression test and the heat build-up is the least when NR to ENR ratio is 80 to 20. Scanning electron microscopy was used to investigate the morphology of NR/silica filled with ENR. It is found that silica self-aggregation was improved in the presence of ENR and sea-island structure was formed in NR/silica when 30phr ENR added, which maybe the reason of decrement of heat produced during compression.

Controlled Plasma Nitriding for an Optimum Balance between PACVD TiBN Coating Scratch Resistance and Substrate Toughness

2008 ◽  
Vol 373-374 ◽  
pp. 312-317
Author(s):  
Y. He ◽  
I. Apachitei ◽  
Jie Zhou ◽  
Twan Walstock ◽  
J. Duszczyk
Keyword(s):  
Fracture Toughness ◽  
Plasma Nitriding ◽  
Scratch Test ◽  
Scratch Resistance ◽  
Diffusion Layers ◽  
Load Carrying ◽  
Duplex Process ◽  
Duplex Surface Treatment ◽  
Composite Hardness ◽  
Optimum Balance

The plasma nitriding (PN) process in the duplex surface treatment was controlled to create nitrided diffusion layers with depths of 0, 5, 15 and 80 m in the substrate of the DIN 1.2367 hot-work tool steel with the maximum microhardness values of 600, 700, 820 and 1000 HV, respectively. The scratch properties, i.e. the critical loads of cohesion (LC1), adhesion (LC2), breakthrough (LC3) and worn out (LC4), of the PACVD TiBN coating (boride, 5-7 at.%) on these substrates increased linearly with the maximum hardness of the PN diffusion layer. Instead of the composite hardness, the peak scratch hardness was used to describe the load-carrying capacity of the TiBN coating and PN substrate. Deep tensile cracks in the PN substrate with a hardness value of 1000 HV formed during the scratch test at a load as low as 90 N, indicating the low fracture toughness of the substrate. Therefore, an optimum balance between the scratch properties of the coating and the good fracture toughness of the nitrided substrate must be achieved through exercising the control of the PN and PACVD duplex process.

Effect of Porosity on Dynamic Mechanical Properties of Rubber in Compression

1996 ◽  
Vol 69 (2) ◽  
pp. 223-233 ◽  
Author(s):  
Alan I. Kasner ◽  
Eberhard A. Meinecke
Keyword(s):  
Dynamic Properties ◽  
Loss Modulus ◽  
Dynamic Mechanical Properties ◽  
Static Loads ◽  
Filled Rubber ◽  
Storage And Loss Moduli ◽  
Nonlinear Stress ◽  
Stress Raisers ◽  
Different Levels ◽  
Cylindrical Samples

Abstract Cylindrical samples of different levels of porosity were prepared from a model carbon black filled rubber and tested in compression. Dynamic properties were determined with dynamic loads and dynamic displacements superimposed on static loads. Nonlinear stress-strain curves of porous rubber blocks produced a dependence of dynamic properties on the mode of testing. Both storage and loss moduli as well as tan γ were found to depend on the levels of porosity. The loss modulus was found to increase with higher strain levels in porous samples, while the storage modulus changed because of reduced sample stiffness. The dynamic data was in agreement with the results of Goodrich flexometer tests on porous and solid samples. The results suggest that the introduction of porosity reduces service life of rubber parts by providing stress raisers for crack initiation, rather than through changing the dynamic properties.

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