An approach for damage initiation and propagation in metal and carbon fiber hybrid composites manufactured by robotic fiber placement

2022

Polymer Composites

Self Cite

The robotic fiber placement (RFP) process depends on continuous fusion bonding and solidifying of prepreg tows onto a substrate by subjecting them to a compression force and heat flux. However the advantages provided when using the RFP to fabricate the composite structures, it has adverse effects due to the induced residual stresses (RSs). The current work presents the effect of the RFP on the induced RSs in thermoset composites. RFP is utilized to fabricate specimens from carbon fiber reinforced polymers. Effects of placement speed, compression force, heating temperature, heating gas flowrate, and the location of the heat flux outlet nozzle are all included in the present study. A total of 69 flat panels are manufactured under different process conditions. Subsequently, the in‐depth RSs are measured using the incremental hole‐drilling method. Besides, the microstructures of the samples are also analyzed. The results show that the change in process parameters could significantly affect the induced RSs of the thermoset composites. Subjecting the samples to higher thermal and pressure loads would induce more RSs, which are attributed to the occurrence of partial curing during the manufacturing process along with the change in laminate geometry and porosity.

Section: Methodsmentioning

confidence: 99%

“…Table 1 provides the mechanical properties of the material. 39,40 The fiber placement workcell provides the required trajectory,…”

Section: Manufacturing Of Specimensmentioning

confidence: 99%

Evaluation of robotic fiber placement effect on process‐induced residual stresses using incremental hole‐drilling method

2022

Polymer Composites

Self Cite

“…In metal cutting simulations, the J–C constitutive approach is the most widely applied material model for simulating material plasticity (curve bc ), as it accounts for temperature, strain hardening, and strain rate sensitivity effects [ 9 ]. For damage modeling, the J–C damage model [ 25 , 41 ] is widely used; it is either used to fully represent the damage process or accompanied by a damage evolution criterion. When used alone, it corresponds to a case of sudden failure ( Figure 1 , curve abdf ), where it does not capture damage evolution.…”

Section: Damage Modellingmentioning

confidence: 99%

On the Role of Damage Evolution in Finite Element Modeling of the Cutting Process and Sensing Residual Stresses

Elgamal

et al. 2022

Sensors

Self Cite

This study focuses on the role of the damage evolution when estimating the failure behavior of AISI 1045 steel for sensing and measuring metal cutting parameters. A total of five Lagrangian explicit models are established to investigate the effect of applying damage evolution techniques. The Johnson–Cook failure model is introduced once to fully represent damage behavior, i.e., no damage evolution is considered, and as a damage initiation criterion in the remaining approaches. A fracture energy-based model is included to model damage propagation with different evolution rates. Temperature-dependent and temperature-independent fracture energy models are also investigated. Dry orthogonal cutting and residual stresses measurements of AISI 1045 are conducted for validation. The significance of the damage evolution is investigated using honed-tool and sharp-tool models. Including the damage evolution led to a prediction of higher workpiece temperatures, plastic strains, cutting forces, and residual stresses, with no clear differences between linear and exponential evolution rates. The role of damage evolution is more evident when temperature-dependent evolution models are used.

“…The composite samples were manufactured using the automated manufacturing facility in the RMRL Lab, Monash University. The RFP process [34,35] was applied to fabricate the CFRP samples. An industrial manipulator (Yaskawa sk120), as well as a fully automated fiber placement head, were utilized to prepare the composite samples.…”

Section: Composite Manufacturingmentioning

confidence: 99%

On the Sensing and Calibration of Residual Stresses Measurements in the Incremental Hole-Drilling Method

Lai

et al. 2021

Sensors

Self Cite

The current study presents three calibration approaches for the hole-drilling method (HDM). A total of 72 finite element models and 144 simulations were established to calibrate the measurements of the strain sensors. The first approach assumed the stresses acted on the boundaries of the drilled hole and thus analyzed the surrounding displacements field. The second analysis considered the loads on the outer surfaces of the specimen while measuring the strains’ differences between the model with and without the drilled hole. The third approach was more comprehensive as it considered the mechanical and thermal effects of the drilling operations. The proposed approaches were applied to two different materials (AISI 1045 and CFRP). The steel specimens were machined using a CNC lathe while the composite laminates were manufactured using the robotic fiber placement (RFP) process. Subsequently, the residual stresses (RSs) were measured using the HDM. The obtained data were compared with X-ray diffraction measurements for validation. The results showed better estimation of the RSs when utilizing the third approach and clear underestimation of the stresses using the second approach. A divergence in RSs values between the three approaches was also detected when measuring the stresses in the internal layers of the composite laminates.