Effects of Hole Perpendicularity Error on Mechanical Performance of Single-Lap Double-Bolt Composite Joints

Liu, Xueshu; Yang, Yuxing; Wang, Yiqi; Bao, Yan; Gao, Hang

doi:10.1155/2017/2790198

Cited by 10 publications

(5 citation statements)

References 24 publications

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“…In drilling, perpendicularity is the deviation of the hole axis from the ideal cylinder axis with respect to the specified reference point. This geometrical defect reduces the load-bearing capacity of bolted joints causing stress concentration around hole edges [97,98]. The results show perpendicularity increases depending on an increase in feed rate and spindle speed, but the influence of the feed rate is more dominant.…”

Section: Hole Cylindricity and Perpendicularity Analysismentioning

confidence: 96%

The effect of cryogenic machining of S2 glass fibre composite on the hole form and dimensional tolerances

Köklü

Morkavuk

Featherston

et al. 2021

Int J Adv Manuf Technol

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S2 glass fibre reinforced epoxy composites are widely used in aeronautical applications owing to their excellent strength to weight ratio. Drilling glass fibres can be cumbersome due to their abrasive nature and poor thermal conductivity. Moreover, the use of conventional coolants is not desirable due to contamination and additional costs for cleaning the machine part. An alternative is to use environmentally friendly coolants such as liquid nitrogen (LN2) which have been previously employed in machining metals and composites. The current study investigates the effect of drilling S2 glass fibre composite in a bath of LN2. The study aims to evaluate the effect of spindle speed, feed rate and the presence of cryogenic cooling on the form and dimensional tolerances of the hole (hole size, circularity, cylindricity and perpendicularity). Design of experiments and analysis of variance (ANOVA) were used to determine the contribution of the input parameters on the analysed hole quality metrics. Results indicated that drilling S2 glass fibre in a cryogenic bath increased hole size significantly beyond the nominal hole diameter. The hole circularity and cylindricity were reduced compared to holes drilled under dry condition under all cutting parameters due to enhanced thermal stability during the drilling process. The current study aims to provide the scientific and industrial communities with the necessary knowledge on whether cryogenic bath cooling strategy provides better hole quality output compared to dry drilling and other cryogenic cooling strategies which were previously reported in the open literature.

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Section: Hole Cylindricity and Perpendicularity Analysismentioning

confidence: 96%

The effect of cryogenic machining of S2 glass fibre composite on the hole form and dimensional tolerances

Köklü

Morkavuk

Featherston

et al. 2021

Int J Adv Manuf Technol

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show abstract

“…The influence of a hole perpendicularity error on the performance of the composite mechanical joint is presented in ref. [84].…”

Section: Whqvlrq Frpsuhvvlrqmentioning

confidence: 99%

The Influence of Selected Local Phenomena in CFRP Laminate on Global Characteristics of Bolted Joints

et al. 2019

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High specific mechanical properties of composites are the reason for their use in various fields, e.g., the aerospace industry. Mechanical joints are still used in the aerospace industry to assembly large aircraft structures. The properties of laminate around the hole can be, however, weakened, compared to their nominal values as a result of a drilling process or cyclic loading. This paper aims at the classification and analysis of imperfections affecting mechanically fastened joints in a laminate structure. A method of modeling the hole vicinity, a gradient material model, as well as the numerical and experimental estimation of laminate deterioration in this area, were proposed and analyzed. Comparative analysis of numerical and experimental results based on displacements of the testing machine grip and the extensometer length confirmed the aforementioned results as consistent in linear ranges. Therefore, joint characteristics obtained based upon measurement of the grip displacement and the ratio of stiffness in linear ranges are sufficient to determine the parameters of a gradient material model. Some imperfections resulting from, e.g., asymmetry, were included in the gradient material model; thus, the obtained weakening of laminate properties in the hole vicinity can be overestimated. Therefore, further analyses of the gradient material model for laminate structures are necessary.

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“…To minimize the unfavorable effects of perpendicularity error on the joints, increasing the bolt preload becomes an effective method. Further, Xu established a finite element model of composite double-nailed single-shear composites by combining the shear stress-strain relationship and stiffness discounting scheme (Xu, 2017). The load-carrying capacity and load distribution of the joint under different combinations of tilt angle and tilt direction were investigated.…”

Section: Introductionmentioning

confidence: 99%

“…However, the effect of tilt direction on the bearing strength was not significant. Liu et al investigated the effect of hole perpendicularity error on the stress distribution of CFRP screwed joints and analyzed the relationship between the bolt preload and hole perpendicularity error through tests (Liu et al, 2018). It was concluded that the hole perpendicularity error resulted in stress concentration around the hole and nonuniform stress distribution in the joint region.…”

Section: Introductionmentioning

confidence: 99%

Fatigue properties of riveted joints under different hole perpendicularity errors and squeeze forces

Li,

Tian,

Liao

2024

Microscopy Res & Technique

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Riveting is the most important method of joining sheet metal and is widely used in the assembly of aircraft components. The perpendicularity error of the holes is unavoidable during automatic drilling and riveting, which has a significant impact on the quality of the assembly. In this paper, the effects of hole perpendicularity error and squeeze force on the interference fit size, interface contact state, microstructure morphology, fatigue life, and fracture form of riveted joints were investigated experimentally. The results show that the interference fit size increases with a greater tilt angle. When the tilt angle is 0°, the rivet shank is in close contact with the inner and outer sheets, and there is no obvious gap at the interface between the rivet and the sheets. As the tilt angle increases to 2° and 4°, a gap appears at the interface of regions 1, 2, and 3, while the rivet shank at region 4 is in close contact with the outer sheet. The fatigue life decreases when the tilt angle increases from 0° to 4°. For the same tilt angle, the fatigue life of riveted joints with a 0° tilt direction is higher than that of riveted joints with a 180° tilt direction. Increasing the squeeze force can to some extent reduce the adverse effect of the tilt angle on the fatigue life. The hole perpendicularity error does not affect the failure form, while the squeeze force has a significant effect on the failure form of the specimens.Research Highlights The fatigue life of riveted joints decreases as the tilt angle increases. The size of the interfacial gap increases with increasing tilt angle. Higher fatigue life at 0° tilt direction than at 180° tilt direction. Increasing the squeeze force can somewhat reduce the negative effect of tilt angle on fatigue life.

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Effects of Hole Perpendicularity Error on Mechanical Performance of Single-Lap Double-Bolt Composite Joints

Cited by 10 publications

References 24 publications

The effect of cryogenic machining of S2 glass fibre composite on the hole form and dimensional tolerances

The effect of cryogenic machining of S2 glass fibre composite on the hole form and dimensional tolerances

The Influence of Selected Local Phenomena in CFRP Laminate on Global Characteristics of Bolted Joints

Fatigue properties of riveted joints under different hole perpendicularity errors and squeeze forces

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