Statistical life prediction of unidirectional carbon fiber/polypropylene tape under creep tension load

2020 ◽  
Vol 39 (7-8) ◽  
pp. 278-284 ◽  
Author(s):  
Masayuki Nakada ◽  
Yasushi Miyano ◽  
Yoko Morisawa ◽  
Takeharu Isaki ◽  
Taiki Hirano ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Elevated Temperatures ◽  
Constant Strain Rate ◽  
Test Method ◽  
Creep Failure ◽  
Creep Tests ◽  
Failure Times ◽  
The Matrix ◽  
Tension Loading ◽  
Polypropylene Tape

Recently, a carbon fiber/polypropylene unidirectional sheet has been developed by Mitsui Chemicals, Inc. from a new polyolefin-based sizing agent for carbon fiber. Its effective polypropylene modification brings good compatibility with polypropylene to improve the fiber matrix adhesion. This study examines the prediction of the statistical lifetime of this developed carbon fiber/polypropylene unidirectional sheet under creep tension loading. First, a tensile test method for static and creep strengths at elevated temperatures was developed for carbon fiber/polypropylene unidirectional tape cut from a carbon fiber/polypropylene unidirectional sheet. Second, the static tensile strengths of carbon fiber/polypropylene tape were measured statistically at various constant temperatures under a constant strain rate. The statistical creep failure times under tension loading for carbon fiber/polypropylene tape were predicted at a constant temperature by substituting the statistical static strengths into the formulation based on the matrix resin viscoelasticity. Third, the validity of the predicted results was clarified by comparison with the creep failure times measured statistically using creep tests for carbon fiber/polypropylene tape. Finally, the relation between the failure probability and creep failure times for carbon fiber/polypropylene unidirectional tape at various loads and temperature conditions was discussed.

Prediction of statistical life time for unidirectional CFRTP under cyclic loading

2021 ◽  
pp. 073168442110055
Author(s):  
Masayuki Nakada ◽  
Yasushi Miyano ◽  
Soshi Kageta ◽  
Hirofumi Nishida ◽  
Yutaka Hayashi ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Epoxy Resin ◽  
Elevated Temperatures ◽  
Constant Strain Rate ◽  
Life Time ◽  
Fiber Reinforced ◽  
Statistical Life ◽  
The Matrix ◽  
Carbon Fiber Reinforced ◽  
Thermoset Epoxy

Recently, the Innovative Composite Center of Kanazawa Institute of Technology developed a thermoplastic epoxy resin (TP-EP). Resin-impregnated carbon fiber reinforced TP-EP (CF/TP) strands molded by pultrusion were developed by Komatsu Matere Co., Ltd., for use as tension rods. This study examines the prediction of the statistical life time for these developed CF/TP strands under cyclic tension loading with comparison to our earlier report of similar predictions for carbon fiber reinforced thermoset epoxy resin (CF/TS) strands having a thermoset epoxy resin (TS-EP) as a matrix. First, test methods for static and fatigue strengths at elevated temperatures were developed for CF/TP strands. Second, static and fatigue tensile strengths of CF/TP strands were measured statistically at various constant temperatures under a constant strain rate and frequency. The master curves of statistical fatigue tensile strengths for CF/TP strands were constructed by substituting the measured data into the formulations of these strengths based on the matrix resin viscoelasticity. The fatigue strength characteristics of CF/TP strands were discussed through comparison to those of CF/TS strands with thermosetting epoxy resin as the matrix.

scholarly journals Temperature dependence of statistical fatigue strengths for unidirectional carbon fiber reinforced plastics under tension loading

2019 ◽  
Vol 54 (14) ◽  
pp. 1797-1806 ◽  
Author(s):  
Masayuki Nakada ◽  
Yasushi Miyano
Keyword(s):  
Fatigue Strength ◽  
Carbon Fiber ◽  
Longitudinal Direction ◽  
Fiber Reinforced ◽  
Carbon Fiber Reinforced Plastics ◽  
Reinforced Plastics ◽  
The Matrix ◽  
Fiber Reinforced Plastics ◽  
Carbon Fiber Reinforced ◽  
Tension Loading

The formulation for time- and temperature-dependent statistical static and fatigue strengths for carbon fiber reinforced plastics laminates is newly proposed based on the physically serious role of resin viscoelasticity as the matrix of carbon fiber reinforced plastics. In this study, this formulation is applied to the tensile strength along the longitudinal direction of unidirectional carbon fiber reinforced plastics constituting the most important data for the reliable design of carbon fiber reinforced plastics structures which are exposed to elevated temperatures for a significant period of their operative life. The statistical distribution of the static and fatigue strengths under tension loading along the longitudinal direction of unidirectional carbon fiber reinforced plastics were measured at various temperatures by using resin-impregnated carbon fiber reinforced plastics strands as specimens. The master curves for the fatigue strength as well as the static strength of carbon fiber reinforced plastics strand were constructed based on the time–temperature superposition principle for the matrix resin viscoelasticity. The long-term fatigue strength of carbon fiber reinforced plastics strand can be predicted by using the master curve of fatigue strength.

scholarly journals Microstructural Evolution of 9CrMoW Weld Metal in a Multiple-Pass Weld

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 847
Author(s):  
Yu-Lun Chuang ◽  
Chu-Chun Wang ◽  
Tai-Cheng Chen ◽  
Ren-Kae Shiue ◽  
Leu-Wen Tsay
Keyword(s):  
Weld Metal ◽  
Elevated Temperatures ◽  
Creep Condition ◽  
Heating System ◽  
Infrared Heating ◽  
Coarse Grained ◽  
Intergranular Cracking ◽  
Creep Failure ◽  
Creep Tests ◽  
Multiple Pass

9CrMoW steel tubes were welded in multiple passes by gas-tungsten arc welding. The reheated microstructures in the Gr. 92 weld metal (WM) of a multiple-pass weld were simulated with an infrared heating system. Simulated specimens after tempering at 760 °C/2 h were subjected to constant load creep tests either at 630 °C/120 MPa or 660 °C/80 MPa. The simulated specimens were designated as the over-tempered (OT, below AC1, i.e., WT-820T) and partially transformed (PT, below AC3, i.e., WT-890T) samples. The transmission electron microscope (TEM) micrographs demonstrated that the tempered WM (WT) displayed coarse martensite packets with carbides along the lath and grain boundaries. Cellular subgrains and coarse carbides were observed in the WT-820T sample. A degraded lath morphology and numerous carbides in various dimensions were found in the WT-890T sample. The grain boundary map showed that the WT-820T sample had the same coarse-grained structure as the WT sample, but the WT-890T sample consisted of refined grains. The WT-890T samples with a fine-grained structure were more prone to creep fracture than the WT and WT-820T samples were. Intergranular cracking was more likely to occur at the corners of the crept samples, which suffered from high strain and stress concentration. As compared to the Gr. 91 steel or Gr. 91 WM, the Gr. 92 WM was more stable in maintaining its original microstructures under the same creep condition. Undegraded microstructures of the Gr. 92 WM strained at elevated temperatures were responsible for its higher resistance to creep failure during the practical service.

Ultimate Tensile Properties of Elastomers. I. Characterization by a Time and Temperature Independent Failure Envelope

1964 ◽  
Vol 37 (4) ◽  
pp. 777-791 ◽  
Author(s):  
Thor L. Smith
Keyword(s):  
Strain Rate ◽  
Tensile Properties ◽  
Elevated Temperatures ◽  
Constant Strain Rate ◽  
Test Methods ◽  
Constant Stress ◽  
Test Method ◽  
Failure Envelope ◽  
Polymeric Network ◽  
Time To Rupture

Abstract The tensile stress at break (σb) and the associated ultimate strain (εb) of an elastomer depend on (1) the chemical and topological characteristics of the polymeric network, and (2) the test conditions under which rupture is observed. To separate these effects, the ultimate tensile properties can often be characterized by a “failure envelope” defined by values of σb and εb determined at various strain rates over a wide temperature range. Provided time—temperature superposition is applicable, such data superpose on a plot of log σbT0/T versus log εb, where T is the test temperature (absolute) and T0 is an arbitrarily selected reference temperature. The resulting failure envelope is independent of time (strain rate) and temperature and thus it depends only on basic characteristics of the polymeric network. To illustrate the characterization method, data on two styrene-butadiene gum vulcanizates, SBR-I and SBR-II, were analyzed. For SBR-I, values of σb and εb obtained over extensive ranges of strain rate and temperature superposed to give a failure envelope. Data at elevated temperatures also gave a reliable value for the equilibrium modulus. For SBR-II, data obtained at various temperatures under conditions of constant strain and constant strain rate yielded identical failure envelopes; this strongly suggests that the failure envelope is independent of the test method. A theoretical consideration of the time-to-rupture associated with different test methods showed that for given values of σb and εb the time-to-rupture from the following types of tests should increase in the order: constant strain < constant stress < constant strain rate < constant stress rate.

Room and Elevated Temperature Mechanical Properties of Hot-Pressed Uni-Cf/SiO2 Composite

2007 ◽  
Vol 546-549 ◽  
pp. 1509-1514 ◽  
Author(s):  
G.H. Zhou ◽  
Shi Wei Wang ◽  
Xiao Xian Huang ◽  
Jing Kun Guo
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Flexural Strength ◽  
Elevated Temperatures ◽  
Fused Silica ◽  
Silica Matrix ◽  
Flexural Properties ◽  
Catastrophic Failure ◽  
The Matrix ◽  
Fracture Features

Unidirectional carbon fiber reinforced fused silica (uni-Cf/SiO2) composite was prepared by slurry infiltration and hot-pressing. The room and elevated temperatures flexural properties were investigated and the fracture features of the composite were observed. This composite exhibited non-catastrophic failure at room and elevated temperatures. The oxidation of carbon fiber at elevated temperatures was the main reason for the degradation of flexural strength and elastic modulus. The flexural strength tested at 1200 was 376MPa and exhibited anomalously higher than that at 1000 (277MPa), which was attributed to the viscous flow of fused silica matrix and therefore the occurrence of microcracking in the matrix was deferred. And it was inferred that the brittle to plastic transition temperature (Tb-p) of uni-Cf/SiO2 composite corresponded to a certain temperature around 1200°C.

Sign in / Sign up

Export Citation Format

Share Document