# A Model to Study the Creep Behavior of Carbon Fiber/Epoxy Resin Composites Under Temperature
## 2 Literature Review
Komatsu Materials Co., Ltd. (Tokyo, Japan) created pultrusion-molded carbon fiber-reinforced TP-EP (CF/TP) strands impregnated with resin for use as tension rods. This material is studied in [28]. Comparisons with CF/TS strands using thermosetting epoxy resin as the matrix were used to discuss the fatigue strength properties of CF/TP strands. Specific issues regarding the creep of carbon-based composite materials are presented in [29; 30; 31]. A study at normal temperature (20 \({}^{\circ}\)C) and cryogenic temperature (\(-\)196 \({}^{\circ}\)C) examines the material characteristics of carbon fiber-reinforced polymers (CFRPs) [32]. The mechanical characteristics and failure behaviors of two CFRP types, both thermoset resins--epoxy (E) and dicyclopentadiene (D)--were assessed. According to the findings, both CFRP types' bending and fatigue strengths rose by about 30% at \(-\)196 \({}^{\circ}\)C as opposed to 20 \({}^{\circ}\)C.  
To create microcomposites, seven carbon fibers were incorporated into two distinct kinds of epoxy resin--one stiff and the other soft [33]. Both short-term and long-term strength testing were conducted on these microcomposites. Three stress levels were used to conduct the long-term tests. The experimental findings showed that matrix characteristics have a significant impact on composites' mechanical performance. It was discovered that stiff epoxy creates composites that are noticeably stronger and resistant to creep rupture. The superior qualities of carbon, Kevlar, and fiber glass--such as their high strength, low density, and resistance to wear--have led to their widespread use in a variety of industries, such as electronics, automotive, aerospace, and civil engineering [34]. The purpose of the mentioned work is to enhance the creep behavior of epoxy composite materials by employing hand-layup techniques to incorporate two types of fiber for reinforcing. To create a composite material, sika epoxy resin is combined once with carbon fiber and once with Kevlar fiber. A thorough understanding of the creep behavior of epoxy composite materials at different weight ratios is provided by experimental and numerical simulation. Specific topics in the study of the creep behavior of carbon fiber composites are presented in [35; 36; 37; 38]. The authors of [39] created an accelerated testing technique (ATM) for composites. This approach uses viscoelasticity and the time-temperature superposition principle for matrix resin to forecast the statistical long-term life of CFRP constructions. Tensile creep experiments were conducted in [40] at 25 and 50 degrees Celsius for two types of epoxy resin matrix composite laminates. The findings show that these materials undergo time-dependent deformation, meaning that the tensile strain rises shortly after the tests start and subsequently falls for the majority of the loading duration. The characteristic creep and the impact of physical aging are shown in these tendencies of growth and decline, respectively. Beginning with the Boltzmann superposition principle, a linear viscoelastic model is created that incorporates both the physical aging effect and the creep temperature effect. Carbon nanofiber (CNF)-enhanced carbon fiber-reinforced polymer (CFRP) laminates were produced using 0.75 weight percent and 0.5 weight percent of the epoxies Sicomin and Ebalta, respectively, and their static and viscoelastic behavior was examined in [41]. The imposed stress level has a significant impact on creep behavior and stress relaxation. Using DMA and TTSP, one study [42] forecasted the long-term viscoelastic characteristics of a tow prepreg. Based on the viscoelasticity of matrix resin, in [43], the authors presented an accelerated testing methodology (ATM) for the statistical life prediction of carbon fiber-reinforced plastics (CFRPs) under creep and fatigue loads. A viscoelastic response matrix in a polymer composite typically exhibits creep behavior.