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Wear modeling and material testing of elastomers G lobal demand for material efficiency increases the need for practical understanding of material wear behavior. Wear control and process optimization are important steps to sustainable development. Wear commonly limits the lifetime of components and can create component failures. Consequently, the attempts to improve and model the processes having wear challenges cause beneficial effects on resource efficiency. Improving component lifetime three times longer will decrease the demand of raw material to one third within the same period of time. The importance of rubber materials, for example the natural rubber, currently produced mainly from hevea brasiliensis in South East Asia is high. Elastomer material products, such as material handling hoses, mill liners, screen panels and pump liners are key components in increasing material efficiency. Wear modeling of elastomers is not well known, because of the complicity on the behavior of elastomers, e.g. rubbers and modeling enables more thorough and deeper understanding of wear phenomena. However, improved material solutions and speeding up the product design cycle can be guaranteed only by comprehending the underlying mechanisms. This also decreases the experimental laboratory testing time and improves the accuracy of exploiting the results. Novel modeling methods can gradually be applied in a modeling assisted material design process to couple material nano-microstructure and composition to performance of a component. Moreover, multiscale material modelling is the only scientifically sound way to predict the lifetime in materials that meet high wear, which for a wear problem can contain finite and discrete element means enabling computational analysis of material behavior in process environments. Nevertheless, modeling of elastomer behavior at that accuracy is a very demanding task. Modeling relies on experimental testing of actual rubber material mechanical properties and failure and wear models on material behaviour under impact type surface attacks and erosive environments. VTT has developed and offers solid experience and advanced computational tools, VTT ProperTune™, to tackle even Modeled single impact with several rubber thickness on the substrate material. the most complex material design challenges. The constitutive model of the elastomer material developed comprises of hyperelastic and viscoelastic contributions. The material model is normally calibrated by fitting using a single material point model to experimental results. The experimental results for hyperelasticity comprise of tensile, compression and shear tests at different strain rates. Viscoelasticity is determined from creep tests by utilizing the determined creep curves and dynamic mechanical testing. The tensile, compression and shear tests are conducted with servohydraulic material testing machine. Dynamic mechanical analysis can be carried on with the dynamical mechanical analyser (DMA) most reliable in shear Kumiviesti 1/2014 27 Centrifugal accelerator produces dry erosion tests simultaneously for 15 samples. mode in order to obtain frequency dependent viscoelastic material parameters, such as storage and loss modulus values, also in a function of temperature. The material can be subjected to several different kinds of conditions during its service. Thus, more than one type of testing with various conditions and parameters is needed to assess the wear properties of the materials. The model verification is reasonable to conduct by several performance testing devices in laboratory conditions such as scratching and sliding conditions, impacting and erosive condition as well as in severe abrasive conditions. Tampere Wear Center (TWC) at the Department of Materials Science, Tampere University of Technology has rapidly developed into an internationally recognized concentration of advanced wear expertise and test facilities. Several devices have been designed to simulate actual wear conditions especially in the field of heavy abrasive and impact wear. Many of the methods are suitable also for wear testing of rubber materials. Experimental rubber surface single scratch testing is used as model verification. Penetration depth dependence on the applied force in scratch testing for rubber materials simulates the hard par- ticle influence in the industrial slurries and effect on the rubber liner surfaces. Scratch tester (CSM Micro Combi Tester) in VTT Technical Research Centre Espoo is in constant environment in tribology laboratory (22 ± 1 °C, RH 50 ± 5 %). The parameters for scratch testing can be for instance following: scratch length 5 mm and linearly increasing load from 100 mN to 1000 mN with loading rate of 1800 mN/min during the experiments. The penetration depth is measured during the scratch test and post scan can be carried out for measuring the residual depth. High velocity particle impactor (HVPI) at Tampere Wear Center conduct High speed video frames of the HVPI tests for rubber. 28 Kumiviesti 1/2014 impact tests where the experimental parameters such as the shape and size of the impacting particle and its velocity and impact angle are strictly controlled. The HVPI data is used to verify and calibrate the numerical simulations based on the high-speed video recording. The device is capable of shooting 9 mm projectiles of different shape and composition to a fixed target at velocities ranging from 30 to 200 m/s. Erosion testing at Tampere Wear Center using centrifugal accelerator produces impacts with lower loads but higher volume. The amount of abrasive is up to 10 kg. However, the particle size of the abrasive is smaller than 1 mm. The samp- High-speed slurry-pot type erosion tester is suitable for testing of metals, coatings, polymers, and elastomers. le angles vary from 15° to 90° and all angles can be tested simultaneously. High-speed slurry-pot type erosion tester was developed at TWC for slurry or dry erosion testing with high speeds and various sizes of particles. In this pin mill type tester, several samples are attached horizontally to a rotating central shaft on various levels. The strong and durable structure enables testing of 8 materials simultaneously also with large size abrasives using rotating speeds up to 2000 rpm. The crushing pin-on-disc test method at TWC, which is based on the common pin-on-disc principle, is used to determine the abrasion wear resistance with a loose abrasive. The abrasive is placed between the rotating disc and the pin, which is cyclically pressed against the abrasive. The pin and the disc are not in direct contact at any point of the test. Thus, the abrasive is rolling and sliding, producing demanding abrasion wear conditions. Friction and Wear of Polymers project (2009–2014) is the TEKES funded DEMAPP program of FIMECC Ltd that concentrates on wear modeling and material testing of elastomers. The material data for modeling was collected using DMA, and tensile, compression and shear tests at different strain rates. Scratch testing and high velocity particle impactor tests were utilized for verification of the models. Moreover, various wear tests, such as dry erosion and slurry erosion tests, increased understanding of the material behavior and wear mechanisms of various rubber materials under erosive environments. The general target of the project was to develop a suitable and reliable modeling method for elastomer life time estimation and extension. Päivi Kivikytö-Reponen and Anssi Laukkanen, VTT Kati Valtonen and Marian Apostol, Tampere Wear Center, Department of Materials Science, Tampere University of Technology Heavy abrasion wear tests are produced by crushing pin-on-disc. Kumiviesti 1/2014 29