The use of composite joints has been increased in recent years in structural applications such as aircraft, civil engineering structure, ship structure, wind energy sector, and automotive industry. All previous efforts focused on bolted and riveted connections loaded in shear (in-plane loading) either in single or double lap joints. No work in literature that addresses the analysis of bolted connection in glass fibre reinforced plastics loaded in tension. Such joint configuration is essential in connections of wind turbine blades, in particular for vertical axis wind turbine blades, where the blade is connected to the rotor in bolted connections loaded in tension. In this paper, the behaviour of composite bolted connection joints under out of plane loading was investigated. A parametric study was conducted to study the joint stiffness variation with different parameters such as the ratio between edge distance (e) and bolt diameter (D), e/D, plate width (W) to bolt diameter ratio, W/D, stacking sequence and bolt load. The effect of the fillet radius also investigated to determine the minimum radius which prevents the onset of delamination between stacked layers. The experimental work was conducted on GFRP tension clips (L-angle) joint specimens manufactured by the vacuum infusion technique. Large samples of dimensions 1 m long were first produced and then cut into different specimen sizes. Holes are then drilled carefully at specific locations to avoid inducing damage to the specimen before testing. In the present work, three types of laminates were used; a unidirectional laminates with an areal density of 1050 gm/m2, biaxial laminates, 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. A 3D finite element (FE) model was developed to study the effect of joint parameters on its stiffness and the resulting failure modes. Finite element models were constructed and the experimental results were used to validate these finite element models. The finite element model was based on continuum shell elements and was used in conjunction with Hashin’s failure criteria for fibre reinforced polymer composites. The finite element results were validated against experimental results. The analysis concluded that the failure load increases when the edge distance to bolt diameter ratio (e/D) increases and the biaxial stacking sequence is better than unidirectional and the fillet radius affect significantly in the onset of delamination. The (e/D) ratio, stacking sequence, and fillet radius are very significant parameter.


Analysis of Composite Bolted Connection Joints Under Out of Plane Loading

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

IMECE2020 - Virtual Conference

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.