Effect of Mean Stress on Fatigue Strength of Short Glass Fiber Reinforced Polybuthyleneterephthalate

Tension-compression fatigue tests under various mean stress conditions were conducted with round bar specimens of short glass fiber reinforced polybuthyleneterephthalate made by injection molding. Under cyclic loading with high mean stresses, the creep phenomenon became predominant and the ratcheting deformation increased with the number of cycles. This phenomenon is characteristic of plastics including short glass fiber reinforced plastics. The experimental data of the fatigue strength at the stress ratios above 0.7 were lower than the prediction based on the modified Goodman diagram. We propose to use the creep rupture strength, σc, instead of the tensile strength, σB, as the strength without mean stress and the parabolic equation for a constant life in the amplitude-mean stress (σa-σm) diagram. Our new design equation for the mean-stress effect on the fatigue strength on plastics is as follows: σa = σw – (σw / σc 2) σm 2, where σw is the fatigue strength at the stress ratio R=-1 and σa is the stress amplitude under a mean stress of σm. We also proposed a method to obtain the constant-life relation from limited experimental data.

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Effect of frequency upon fatigue strength of a short glass fiber reinforced polyamide 6: A superposition method based on cyclic creep parameters

Polymer Composites ◽

10.1002/pc.20543 ◽

2009 ◽

Vol 30 (2) ◽

pp. 154-161 ◽

Cited By ~ 27

Author(s):

Andrea Bernasconi ◽

Robb M. Kulin

Keyword(s):

Fatigue Strength ◽

Glass Fiber ◽

Cyclic Creep ◽

Polyamide 6 ◽

Superposition Method ◽

Fiber Reinforced ◽

Short Glass Fiber ◽

Glass Fiber Reinforced ◽

Short Glass

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A Fatigue Damage Model for Life Prediction of Injection-Molded Short Glass Fiber-Reinforced Thermoplastic Composites

Polymers ◽

10.3390/polym13142250 ◽

2021 ◽

Vol 13 (14) ◽

pp. 2250

Author(s):

Mohammad Amjadi ◽

Ali Fatemi

Keyword(s):

Injection Molding ◽

Glass Fiber ◽

Fatigue Damage ◽

Life Prediction ◽

Glass Fibers ◽

Damage Model ◽

Fiber Reinforced ◽

Short Glass Fiber ◽

Glass Fiber Reinforced ◽

Short Glass

Short glass fiber-reinforced (SGFR) thermoplastics are used in many industries manufactured by injection molding which is the most common technique for polymeric parts production. Glass fibers are commonly used as the reinforced material with thermoplastics and injection molding. In this paper, a critical plane-based fatigue damage model is proposed for tension–tension or tension–compression fatigue life prediction of SGFR thermoplastics considering fiber orientation and mean stress effects. Temperature and frequency effects were also included by applying the proposed damage model into a general fatigue model. Model predictions are presented and discussed by comparing with the experimental data from the literature.

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Material Selection and Application of Abrasive-Liquid Device Sealing Bush

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.127.110 ◽

2011 ◽

Vol 127 ◽

pp. 110-114

Author(s):

Rui Zeng ◽

Chang Long Du ◽

Jing Zhao ◽

Rui Xu

Keyword(s):

Glass Fiber ◽

Abrasive Water Jet ◽

Fiber Reinforced ◽

Short Glass Fiber ◽

Glass Fiber Reinforced ◽

Water Jet Cutting ◽

Weight Content ◽

Abrasive Water Jet Cutting ◽

Cutting System ◽

Short Glass

In order to make the switch valve in abrasive-liquid device of premixed abrasive water jet cutting system work normally, the sealing bush which ensures the pressure constant and the switch smooth is needed. The structure, material and craft of the switch valve sealing bush are studied in this paper. The different weight content of short glass fiber reinforced nylon is tested in the environment of no lubricant, water lubricant and oil lubricant. The result shows that in oil lubricant environment, the 33% weight content of short glass fiber reinforced nylon composites have the best capabilities and the least resistance of friction. The experimental result proves that the sealing bush made by the prepared short glass fiber reinforced nylon composites can meet the require of the premixed abrasive water jet cutting system, according to which the sealing bush is producted and assembled to the abrasive-liquid device.

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