Calibration of the PA6 Short-Fiber Reinforced Material Model for 10% to 30% Carbon Mass Fraction Mechanical Characteristic Prediction

Abstract

Short-fiber reinforced composites are widely used for the mass production of high-resistance products with complex shapes. Efficient structural design requires consideration of plasticity and anisotropy. This paper presents a method for the calibration of a general material model for stress–strain curve prediction for short-fiber reinforced composites with different fiber mass fractions. A Mori–Tanaka homogenization scheme and the J2 plasticity model with layered defined fiber orientation were used. The hardening laws: power, exponential, and exponential and linear were compared. The models were calibrated using experimental results for melt front, orientation tensor analysis, fiber length, and diameter and tension according to ISO 527-2, for samples of PA6 which were either non-reinforced, or reinforced with 10%, 15%, 20%, and 30% carbon fiber mass fractions. The novelty of this study lies in the transition from the strain–stress space to the strain–stress–fiber fraction space in the approximation of the material model parameters. We found it necessary to significantly reduce the fiber aspect ratio for the correct prediction of the mechanical characteristics of a composite using the Mori–Tanaka scheme. This deviation was caused by the ideal solution of ellipsoidal inclusion in this homogenization scheme. The calculated strength limits using Tsai–Hill failure criteria, based on strain, could be used as a first approximation for failure prediction.

Evaluation of SFRP Lugs with SLM Bushing Load Capacity and Dependence of CZM Mode II Model Parameters on Embedded Elements Surface Roughness

“…Tensile tests were performed on type 1BA samples according to the ISO 527-2 standard of polyamide-6 reinforced with 30% of the mass with short carbon fibers (Gamma-plast UPA 6 30 M) on a universal testing machine Zwick/Roell Z050 TE (see Figure 1). The compliance of the material model used in the strength calculations [64] with the mechanical characteristics of the samples in molding direction was confirmed.…”

“…The material chosen for the lug is polyamide-6, reinforced with 30% short carbon fibers -a structural material with high weight efficiency and the technological ability to be molded using thermoplastic machines at temperatures from 220 to 270 °C. The study of the characteristics of the short-reinforced polyamide used for the manufacture of lugs is presented in detail in [64] and includes the determination of the parameters of anisotropic models of the material used in the current work for numerical modeling. VT6 titanium, widely used for the SLM process and capable of withstanding high contact stresses, was chosen as the material for the embedded elements.…”

“…The bilinear CZM model was used [65]. Since mode II has the greatest impact on reducing the mass of the entire lug [64], we choose a model based on mode II as the basis for predicting the load-bearing capacity of the lugs.…”

Short Fiber-Reinforced Polymer Polyamide 6 Lugs and Selective Laser-Melted Ti-6Al-4V Bushing Contact Cohesive Zone Model Mode II Parameters’ Evaluation

“…The material chosen for the lug is polyamide-6, reinforced with 30% short carbon fibers-a structural material with high weight efficiency and the technological ability to be molded using thermoplastic machines at temperatures from 220 to 270 • C. The study of the characteristics of the short-reinforced polyamide used for the manufacture of the lugs is presented in detail in [62] and includes the determination of the parameters of anisotropic models of the material used in the current work for numerical modeling. VT6 (Ti-6Al-4V) titanium, widely used for the SLM process and capable of withstanding high contact stresses, was chosen as the material for the embedded elements.…”

Optimization of Charpy‐impact strength of 3D‐printed carbon fiber/polyamide composites by Taguchi method

“…The aerospace industry has employed the potential of short‐fiber reinforced thermoplastics in various components of the A340‐600 and A350 XWB, and V‐22 tilt‐rotor aircraft. [ 37 ] These components are typically manufactured through extrusion compounding and injection molding processes. To determine potential uses for 3D‐printed CF/PA parts, a comparison of the mechanical performance between CF/PA composites produced by 3D printing and those produced through injection molding/extrusion should be conducted using the same quantity of carbon fibers.…”