Glass Fiber Reinforced Plastics (GFRP) have been used increasingly in many fields such as aerospace, automotive and wind energy sectors. This increase is primarily due to their superior strength-to-weight ratio and excellent fatigue resistance compared to traditional materials. During the manufacturing process of glass fibre reinforced plastics using vacuum assisted resin infusion, some defects such as dry spots and air pockets may develop in the impregnated fabric, especially, when metallic inserts are used. This is particularly true for large and complex structures produced by vacuum assisted resin infusion. While computer simulations can be used to determine the flow and vacuum lines in the infusion process to eliminate such defects, they still can form in special circumstances, such as improper curing, interrupted flow, or the presence of metallic layers. These dry spots can be repaired either by re-infusion or hand wetting rather than scrapping the whole structure. To evaluate the interface between the original and repaired part, an experimental investigation was performed to study its effect on the mechanical properties and structural integrity. Experimental work based on partially infused and repaired samples was conducted. In this case, samples with dimensions of 50x50 cm with different laminates having different areal densities were prepared for vacuum assisted resin infusion. In the present work, three types of laminates were used; a unidirectional laminates with an areal density of 1050 gm/m2, triaxial laminates 0 / +45  / -45 with an areal density of 1200 g/m2, triaxial laminates 90 / +45 / -45 with an areal density of 900 g/m2. The fabrication process was then interrupted and the resulting sample was then re-infused (repaired) after complete curing of the first infusion. Samples from the first infused sample (intact) and re-infused sample are cut into standard tensile and bending specimens. To compare the response of the re-infused (repaired) and intact samples, several tensile and bending tests were performed for uniaxial, biaxial, and triaxial reinforcing fabrics with different interfaces. The results showed that the re-infusion had a minor effect on the ultimate tensile strength, particularly when the parent and repair laminates have almost the same quality. Based on visual inspection of intact samples, it is noted that each type of interface has a typical dominant failure mode. For the re-infused samples, the properties of parent and repair laminates determined the failure location. Furthermore, to quantify the role of the interface angle between the intact and repaired parts, samples with designed interface inclination were prepared using hand wetting techniques on two curing steps. The results obtained are expressed in terms of the interface angle and the type of the fabric.


Evaluation of the Mechanical Properties of Repaired Composite Panels Using Resin Re-Infusion Process

Division / Sponsors: 
Aerospace, Bioengineering, Applied Mechanics, Design Engineering Division, Advanced Energy Systems, Manufacturing Engineering Division, Noise Control and Acoustics, Nondestructive Evaluation, Diagnosis, and Prognosis (NDPD), Nuclear Engineering Division, Process Industries Division, Fluids Engineering, Heat Transfer, Materials, Microelectromechanical Systems, Safety Engineering and Risk Analysis, Computers & Information in Engineering


Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2020/volume/84478

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