• Journal of the Korean Society for Precision Engineering
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• v.26 no.7
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• pp.99-104
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• 2009

Creep characteristic is an important failure mechanism when evaluating engineering materials that are soft as polymers or used as mechanical elements at high temperatures. One of the popular thermo-elastic plastics, Polyethylene(PE) which is used broadly for engineering purposes, as it has good properties and merits compared to other plastics, was studied for creep characteristic at various level of stresses and temperatures. From the experimental results, the creep limit of PE at room temperature is 75% of tensile strength. Also the creep limits decreased exponentially as the temperatures increased, up to 50% of the melting point. Also the secondary stage among the three creep stages was nonexistent nor was there any rupture failure which occurred for many metals.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.10
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• pp.1137-1143
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• 2012

Creep characteristic is an important failure mechanism when evaluating engineering materials that are soft material as polymers or used as mechanical elements at high temperatures. One of the popular thermo-plastic polymers, Acrylonitrile Butadiene Styrene (ABS) which is used broadly for machine elements material, as it has excellent mechanical properties such as impact resistance, toughness and stiffness compared to other polymers, was studied for creep characteristic at different levels of stress and temperatures. From the experimental results, the creep limit of ABS at room temperature is 80 % of tensile strength which is higher than PE and lower than PC or PMMA. Also the creep limits decreased to linearly as the temperatures increased, up to $80^{\circ}C$ which is the softening temperature of Butadiene ($82^{\circ}C$). Also the secondary stage of creep among the three creep stages for different levels of stress and temperature was non-existent which occurred for many metals by strain hardening effect.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.9
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• pp.78-85
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• 2010

Creep characteristic is an important failure mechanism when evaluating engineering materials that are soft material as polymers or used as mechanical elements at high temperatures. One of the popular thermo-elastic polymers, Polycarbonate(PC) which is used broadly for engineering polymer, as it has excellent mechanical and thermal properties compared to other polymers, was studied for creep characteristic at various level of stresses and temperatures. From the experimental results, the creep limit of PC at room temperature is 85 % of tensile strength. which is higher than PE (75%)at room temperature. Also the creep limits decreased exponentially as the temperatures increased, up to 50 % of the melting point($267^{\circ}C$). Also the first and third stage among the three creep stages was non-existent nor was there any rupture failure which occurred for many metals.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.12
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• pp.1403-1410
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• 2011

Creep characteristic is an important failure mechanism when evaluating engineering materials that are soft material as polymers or used as mechanical elements at high temperatures. One of the popular thermo-elastic polymers, Polymethyl methacrylate(PMMA) which is used broadly for engineering polymer, as it has excellent mechanical and thermal properties compared to other polymers, was studied for creep characteristic at various level of stresses and temperatures. From the experimental results, the creep limit of PMMA at room temperature is 85 % of tensile strength. which is higher than that of PE (75%)at room temperature. Also the creep limits decreased to nil linearly as the temperatures increased, up to $120^{\circ}C$ of the melting point($267^{\circ}C$). Also the first and third stage among the three creep stages were non-existent nor were there any rupture failure which occurred for many metals at high temperatures.