Composite to Metal Joints for the ARPA Man-Rated Demonstration Article

Camponeschi, Eugene T.; Bohlmann, RE; Fogarty, John H.

doi:10.1177/089270579500800105

Cited by 6 publications

(5 citation statements)

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“…EA9394 maintains high compressive strength at high temperatures of 180°C. As the liquid shim was prepared, the mass ratio of the matrix resin to the curing agent is 100 : 17 [39,40]. The steel gaskets with a standard thickness were firstly put both ends of the specimen to control the gap thickness before applying liquid shim.…”

Section: Preparation Of Liquid Shim and Peelable Fiberglass Shimmentioning

confidence: 99%

Effect of Gap and Shims on the Strain and Stress State of the Composite-Aluminum Hybrid Bolted Structure

Yue

et al. 2020

International Journal of Aerospace Engineering

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The composite-aluminum hybrid bolted structures are widely used in aircraft. Due to low molding accuracy of composite components, gaps always occur between components during assembly. In this case, the bolt connection can cause a complex strain and stress state of component. It may adversely affect the mechanical properties or cause local damage of the structure. A simplified model of the composite-aluminum assembly structure was established in this paper. Then, the influence of forced assembly, liquid shim, and peelable fiberglass shim on the strain and stress state of the composite-aluminum hybrid bolted structure was studied. A bolt connection experimental device was designed to apply a preload to the specimen. The strain field on the specimen surface was measured using the 3D-DIC strain measurement system. The finite element model was established to study the interlaminar stress and damage state of composite laminates. It is found that the strain of specimen in the X -direction is mainly affected by the bending deformation, while the strain in the Y -direction is mainly affected by the compression of bolt head. For composite laminates, the strain value in the X -direction can be reduced by 8.31%-70.97% with shims. As for the strain value in the Y -direction, the liquid shim can only reduce it up to 23.93%when the gap is large. In addition, the liquid shim and peelable fiberglass shim cannot reduce the stress value of all interlaminar elements, but it can make the stress distribution more uniform and improve the stress state of the interlaminar element when the shim was more than 0.8 mm.

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Section: Preparation Of Liquid Shim and Peelable Fiberglass Shimmentioning

confidence: 99%

Effect of Gap and Shims on the Strain and Stress State of the Composite-Aluminum Hybrid Bolted Structure

Yue

et al. 2020

International Journal of Aerospace Engineering

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“…31 However, these modulus values are just for the material under quite low load and have not taken into account the stiffness changing in the process of loading to failure because of the super-elastic property of the shim material, considering the limitation and conservation of the proposed technical date for commercial, some researchers have conducted experimental tests in order to find the real mechanical properties of the EA 9394. Such as Bresson et al 32 have carried out dynamic mechanical analysis and tensile tests to relate the dispersion on joint strength to void and particle size and distribution, and Camponeschi et al 33 have performed uniaxial compression tests to study the stress-strain relationship of EA 9394 under compression. The stress-strain curve of the latter, however, is not plotted to failure, since the strain gauges typically debonded prior to specimen failure.…”

Section: Materials Propertiesmentioning

confidence: 99%

The influence of the substrate’s stiffness on the liquid shim effect in composite-to-titanium hybrid bolted joints

Liu

2013

Proceedings of the Institution of Mechanical Engineers, Part G:

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Cast in place liquid shim is usually used to fix the gap/mismatch problems, which occur during assembly process of large aircraft structures. The effect of liquid shim on performances of the assembled structures is influenced not only by thickness and mechanical properties of the shim, but also by the location where the shim is used, that is to say the stiffness of the substrates may have impact on the shim’s effect. To study the usage of shim in composite-to-titanium bolted joints, a three-dimensional finite element method is introduced, and the method incorporates the progressive damage of composite materials, elastic-plastic property of the titanium alloy, super-elastic property of the liquid shim, contact relationships between the joint elements, and real assembly conditions of the mechanical joints. After validating through comparing with the experimental results, the modeling method is adopted to simulate the tensile response of the bolted joints with shims. Furthermore, both the influence of liquid shim layer thickness on the mechanical behaviors of composite-to-titanium bolted joints and the influence of the substrate stiffness on the liquid shim effect are studied in detail. Based on the analysis of the results, it can be concluded that the maximum load, initial joint stiffness and design load of the joints decrease with the increase of liquid shim layer’s thickness; and the effect of liquid shim layer relies heavily on the stiffnesses of the substrates and will reduce when the substrates become stiffer.

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“…The mechanical properties of all the materials are listed in Table 1, 18–20 and the calibrated parameters of EA E120 (similar to EA 9394) are referred from the experimental work for EA 9394. 21,22 The plates and sold shims are subjected to large plastic deformation during the axial loading process. Their mechanical response is described by the Johnson–Cook yield model, and the constitutive and damage parameters are listed in Table 2.…”

Section: Numerical Simulationmentioning

confidence: 99%

Experimental and numerical analyses of the shimming effect on bolted joints with nonuniform gaps

Cheng

Wang

2018

Proceedings of the Institution of Mechanical Engineers, Part C:

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In order to investigate the effect of shim compensation for nonuniform gaps in aircraft assembly, the influence of the shims with different material and parameters on bolted joints is studied in this paper. According to the real material and assembly conditions of the aircraft joint structures, the specimen and experiment are designed to obtain the tensile performance of the joint structures with different shims. A three-dimensional finite element model, which incorporates the Johnson–Cook material property of the alloys, traction-separation law of liquid shims, contact relationships between the joint elements, and boundary conditions of the tensile process, is established with the specimen configurations. After validating through comparing with the experimental results, the modeling method is adopted to simulate the tensile response of the bolted joints with shims. Furthermore, both the influence of the shim material and thickness on the mechanical behaviors of bolted joints is investigated in detail. Shims can considerably reduce the assembly stress of joint structures and improve the joint stiffness and load capacity, and this effect is more remarkable with the increase of gap values. Liquid shims improve the joint stiffness due to its cohesive ability, while solid shims improve the joint load capacity. Hybrid shims possess a composite shimming effect of liquid and solid shims. Whatever the shim material is applied, the joint stiffness and strength drop with the growth of shim thickness, so strict deviation control method should be taken to ensure the assembly gaps as small as possible. The research results enhance the knowledge of shimming effect on joint structures, and thus offer positive guidance for practical application in aircraft assembly.

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Composite to Metal Joints for the ARPA Man-Rated Demonstration Article

Cited by 6 publications

References 0 publications

Effect of Gap and Shims on the Strain and Stress State of the Composite-Aluminum Hybrid Bolted Structure

Effect of Gap and Shims on the Strain and Stress State of the Composite-Aluminum Hybrid Bolted Structure

The influence of the substrate’s stiffness on the liquid shim effect in composite-to-titanium hybrid bolted joints

Experimental and numerical analyses of the shimming effect on bolted joints with nonuniform gaps

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