Goncalves et al 2023a - Revision history

Marherna at 15:03, 17 October 2023

2023-10-17T15:03:18Z

Marherna: Marherna moved page Review 922808689996 to Goncalves et al 2023a

2023-06-05T08:20:18Z

Marherna moved page Review 922808689996 to Goncalves et al 2023a

Pauloccs at 10:12, 1 June 2023

2023-06-01T10:12:26Z

Pauloccs at 08:58, 1 June 2023

2023-06-01T08:58:56Z

Pauloccs: Pauloccs moved page Draft Teixeira 797800356 to Review 922808689996

2023-05-22T07:24:29Z

Pauloccs moved page Draft Teixeira 797800356 to Review 922808689996

Pauloccs: Created page with "

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 '''RESUMEN:''' Durante la fabricación de polímeros reforzados con fibra de carbono (CFRP) termoestables, se producen esfuerzos micro residuales dentro del material debido a la disimilitud entre las propiedades térmomecánicas y químicas entre la fibra y el polímero. En aplicaciones criogénicas, la variación de temperatura desde la temperatura ambiente hasta la temperatura de operación, donde por ejemplo el nitrógeno líquido que está a -196°C, implica un cambio de temperatura de más de 300°C considerando la temperatura de curado. Este cambio de temperatura desarrolla tensiones microrresiduales, y tensiones residuales en las laminas que pueden activar prematuramente mecanismos de falla transversal o microfisuras, reduciendo el rendimiento efectivo del recipiente a presión. En este trabajo se desarrolló un modelo 3D utilizando elementos finitos del recipiente a presión de CFRP, considerando una discretización a nivel de meso-escala, con las orientaciones reales de las laminas y de los perfiles de espesores, para estudiar las tensiones residuales termo-mecánicas y la resistencia remanente en condiciones criogénicas bajo presión interna. El modelo de material se calibró con ensayos experimentales del material compuesto unidireccional a temperatura ambiente y a temperatura criogénica. Los resultados muestran que las tensiones residuales termomecánicas pueden alcanzar más del 50% de la resistencia transversal de la lámina, y es posible obtener una falla transversal prematura en la lamina del compuesto si no se tienen en cuenta estos efectos durante el diseño.
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 ==1. Introduction==

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 '''ABSTRACT:''' During the manufacturing of thermoset-based Carbon Fiber Reinforced Polymers (CFRPs), micro-residual stresses are developed within the material due to the different chemical-thermal-mechanical properties of the fiber and the polymer. Considering cryogenic applications, the temperature change from ambient temperature to operating conditions (for example  in liquid nitrogen which is at -196°C) involves a temperature change of more than 300°C considering curing temperature from manufactuing. This temperature change develops micro-residual stresses and ply residual stresses that could trigger premature transverse failure or micro-cracking, reducing the effective mechanical performance of the pressure vessel. In this work, a 3D finite element model of the CFRP pressure vessel is developed considering a discretization at meso-scale level, with the actual ply stack orientations and thickness profiles to study the thermo-mechanical residual stresses and the remaining pressure load carrying capacity at cryogenic conditions. The material model was calibrated with experiments on the unidirectional composite at ambient temperature, and cryogenic temperature. The results show that the thermo-mechanical residual stresses can achieve more than 50% of the ply transverse strength, pressure load carring capacity is reduced and premature transverse failure can be triggered if these effects are not considered during design.
-'''Keywords: '''Carbon fiber reinforced polymers; Composite overwrapped pressure vessel; Residual/internal stresses; Finite element analysis.
+'''Keywords: '''Carbon fiber reinforced polymers; Composite overwrapped pressure vessel; Residual/internal stresses; Finite element analysis; Polymeros reforzados con fibra de carbono, Recipientes a presion en compuesto, esfuerzos residuals/internos, análisis por elementos finitos.
 ==1. Introduction==

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 |  style="border: 1pt solid black;text-align: center;"|Trans. Shear modulus
 |  style="border: 1pt solid black;text-align: center;"|<math display="inline">{G}_{T}</math> [GPa]
-|  style="border: 1pt solid black;text-align: center;"|1.26
+|  style="border: 1pt solid black;text-align: center;"|2.48
-|  style="border: 1pt solid black;text-align: center;"|2.39
+|  style="border: 1pt solid black;text-align: center;"|4.46
 |-
 |  style="border: 1pt solid black;text-align: center;"|Long. Thermal Expansion
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 Figure 6. FE model: a) mesh discretization; b) ply orientation; c) thickness profile</div>
-Three different effects are to be considered when evaluating the COPV: the curing stresses, thermal contraction associated with exposure to cryogenic conditions and stresses resulting from internal pressurization. To better understand each contribution, these effects are to be studied in three distinct load cases involving: i) curing cycle, cool down to room temperature and pressurization; ii) curing cycle, cool down to cryogenic temperature and pressurization; iii) cool down to cryogenic temperature and pressurization.
+Three different effects are to be considered when evaluating the COPV: the curing stresses, thermal contraction associated with exposure to cryogenic conditions and stresses resulting from internal pressurization. To better understand each contribution, these effects are to be studied in two distinct load cases involving: i) curing cycle, cool down to room temperature and pressurization; ii) curing cycle, cool down to cryogenic temperature and pressurization.
 ==3. Results==

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