Interlaminar fracture toughness is an important parameter to characterize the delamination performance of carbon fiber-reinforced epoxy laminates. In this study, the mode-I fracture toughness of interlaminar interfaces with different local ply angles were studied by experiments and numerical simulations. A set of double cantilever beam specimens of...
Inter-laminar fracture toughness is an important parameter to characterize the delamination propagation performance of composite laminates. Compared with the mode I fracture, the results of mode II fracture behavior are limited. In this study, the effect of varying ply angle on the mode II delamination behavior of carbon/polymer was studied. T800 c...
Robot based Automated Fiber Placement is one of the most promising manufacturing technologies for the highly automated production of complex parts that involve carbon fiber reinforced plastics. A possible new application in the aerospace field are shell parts that contain sandwich areas. Their complex geometry poses specific challenges. Different a...
The Thermoplastic Automated Fiber Placement process enables the use of blanks with steered fiber architecture in the stamp forming process chain. Fiber steering however can cause defects, such as undulations and gaps, and therefore might decrease the quality of blanks and final parts. An analysis method was developed to characterize the effect of d...
Published in International Journal of Fracture
As part of an effort to predict wrinkling of carbon-fiber tows during automated fiber placement, the cohesive zone traction–separation relations for two carbon fiber epoxy prepreg tows are quantified for Mode I and Mode II loading using a rigid double cantilever beam (RDCB) specimen. An explicit expression for normal traction versus normal separati...
Automated Fiber Placement of thermoplastic unidirectional tape materials offers several advantages over conventional organosheets, such as enhanced part performance through tailored fiber architecture, and economic and ecological benefits due to scrap reduction. Because material is cut perpendicular to the feeding direction in state-of-the-art mach...
Published in Production Engineering
The project “Multi-Layer Inserts” (MLI) proposes a new design for inserts used in thin-walled CFRP structures. The proposed inserts consist of multiple thin metal sheets and is build up simultaneously with the laminate in an intrinsic hybridization process, eliminating time-consuming post-processing steps. Furthermore, at equal weight, such inserts...
Published in Applied Composite Materials
As one of the most common process induced defects of automated fiber placement, in-plane fiber waviness and its influences on mechanical properties of fiber reinforced composite lack experimental studies. In this paper, a new approach to prepare the test specimen with in-plane fiber waviness is proposed in consideration of the mismatch between the ...
Published in Applied Composite Materials
Automated fiber placement (AFP) process can be used to manufacture laminates by laying up unidirectional slit tapes along a desired path and placing multiple layers on top of each other. Usually, the slit tapes are placed direct onto the tooling to attain the final part geometry. Alternatively, the laminate can be built up on a planar substrate and...
This paper examines the vibration of fiber-steered laminated plates, such as those used in the skins of a sandwich panel, manufactured by automated fiber placement. We use third-order shear deformation theory, hybrid Fourier-Galerkin method, and numerical integration technique to predict their vibration responses, and to study the role of manufactu...
