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Composite sandwich structures are being increasingly employed in the aerospace, marine as well as other applications which require high strength, high in-plane and flexural stiffness coupled with a reduction in weight. In the aerospace industry sandwich composites are usually manufactured using the autoclave process which is expensive and time cons...
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... this work, a bilinear traction- separation law is used to simulate the failure behavior of No- mex and K-COR sandwich structures under flatwise tension. Comprehensive three-dimensional finite element models are developed for both Nomex and K-COR sandwich structures in ABAQUS v. 6.10 as shown in Figures 3 and 4 respec- tively. ...
Citations
... Conventional manufacturing processes, such as curing in autoclave, were not preferred in automotive industries due to its high costs and time associated with it [14][15][16]. Recent advancement in the processing of TS composites has created a low cost and low cycle time resintransfer-moulding (RTM) process [17]. ...
Composite materials have gained popularity in automotive industries due to its lightweight potential, good damping behaviour as well as high strength and stiffness properties. Based on the increase in usage of composites, there is a growing interest for a repair technique in the automotive industry. Along with these raise in demand there comes a need for an all-inclusive review article and the objective of this article is to address this need. Two repair techniques, namely scarfing repair and injection repair, have the potential to be used in automotive industry. This paper compiles the various research work done in this field of repairing along with various processing steps associated with it. Further this paper reviews the non-destructive technique that can be used for damage identification and repair assessment.
Sandwich structures with the superior mechanical properties such as high stiffness and strength-to-weight ratio, good thermal insulation, and high energy absorption capacity are used today in aerospace, automotive, marine, and civil engineering industries. These structures are composed of moderately stiff, thin face sheets that withstand the majority of transverse and in-plane loads, separated by a thick, lightweight core that resists shear forces. In this research, the finite element technique is used to simulate a sandwich panel with a truss core under axial compressive stress using ABAQUS software. A review of past experimental studies shows that the bondline between the core and face sheets plays a vital role in the critical failure load. Therefore, this modeling analyzes the damage initiation modes and debonding between face sheet and core by cohesive surface contact with traction-separation model. According to the results obtained from the modeling, it can be observed that the adhesive stiffness has a significant influence on the critical failure load of the specimens. To achieve the full strength of the structure as a continuum, a lower limit is obtained for the adhesive stiffness. By providing this limit stiffness between the core and the panel face sheets, sudden failure of the structure can be prevented.
Z-pinned laminates and sandwich materials are an important class of composites with current applications in aircraft and emerging uses in other light-weight engineered products. This paper reviews research advances in the manufacture, microstructural chacterisation, mechanical properties, environmental durability and other functional properties (e.g. electrical, thermal, damage sensing) of z-pinned composite materials and structures. The review reveals that z-pins can be used in create novel multifunctional laminates that uniquely combine a multitude of important properties including high interlaminar fracture and fatigue resistance, superior impact damage tolerance, increased thermal and electrical conductivities, damage sensing, and high-performance joining. Similarly, z-pins can impart sandwich composites with a novel combination of multifunctional properties that include high structural, damage tolerance, electrical and damage sensing properties. Research gaps in our understanding of z-pinned laminates and sandwich composites are identified. Future research opportunities to create next-generation z-pinned materials with even more versatile multifunctional properties are described.
We developed a portable carbon fiber/epoxy printer that can be used to repair damaged carbon fiber reinforcement plastics (CFRPs). Conventionally, CFRP repair features grinding/excision of the damaged area, attachment of a prefabricated CFRP patch, and curing. The repair patch must match the ground/cut area, and is usually laid-up by hand. Our device prints epoxy-bound carbon fibers directly onto the ground/cut surface. We designed and fabricated a prototype printer and tested its repair capacity. We fabricated and compared simple samples with varying tensile strengths. We compared printer-repaired and hand-laid-up samples; the former samples exhibited higher stiffness. We used simple image processing to verify the differences between the samples.
