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Riveting is a common process to fasten structural parts in industries such as automotive and aircraft. In this paper, the influence of riveting process parameters, namely, riveting force, sheet thickness, friction coefficient and clearance fit are investigated on residual stress field and fatigue life of single riveted lap joint of AA2024 type. Acc...
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... to the symmetry of the joint, only half of the joint was modeled (Fig. 1). Symmetric boundary conditions were applied to the center plane of the joint along the longitudinal direction. As shown in Fig. 1, boundary conditions of the joint were defined during riveting process as: displacement of the remote edges of sheet in y and z direction was set as zero, rivet head was restrained in y direction, and ...
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... to the symmetry of the joint, only half of the joint was modeled (Fig. 1). Symmetric boundary conditions were applied to the center plane of the joint along the longitudinal direction. As shown in Fig. 1, boundary conditions of the joint were defined during riveting process as: displacement of the remote edges of sheet in y and z direction was set as zero, rivet head was restrained in y direction, and symmetry in z direction was defined as mentioned before. The material of the rivet and sheet were defined as the isotropic plasticity ...
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... relationship was derived experimentally by Rijck and co-workers. Figure 10 introduces the parameters which are used in such equation [20]. ...
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... K and n are strain hardening coefficient and strain hardening power, respectively. 0 H , H , 0 D and D are the rivet length out of the sheets before riveting process, rivet length out of the sheets after riveting process, rivet diameter before riveting, and rivet diameter after riveting (all these parameters are introduced schematically in Fig. 10), respectively. As shown in Fig. 11, the results of Eq. (10) were compared with various forces (from 4000 N to 16000 N) as riveting squeeze force and the rivet tail dimensions for each simulation. Finally, FEM results and Rijck's experimental formula illustrated good accordance together. ...
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... coefficient and strain hardening power, respectively. 0 H , H , 0 D and D are the rivet length out of the sheets before riveting process, rivet length out of the sheets after riveting process, rivet diameter before riveting, and rivet diameter after riveting (all these parameters are introduced schematically in Fig. 10), respectively. As shown in Fig. 11, the results of Eq. (10) were compared with various forces (from 4000 N to 16000 N) as riveting squeeze force and the rivet tail dimensions for each simulation. Finally, FEM results and Rijck's experimental formula illustrated good accordance together. ...
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... During the industrialization stages of automobile chassis, mechanical tests are performed on onefourth scale vehicle models using both static and dynamic loads to assess the development of cracks, damages, and the degradation of structural rigidity (force/displacement) over a specified number of cycles, which provides an estimation of durability. Several experiments and recent studies have been conducted to define the mechanical behavior of automobile chassis [8][9][10][11][12]. Duysink [13] employed analytical analysis to investigate the dynamic behavior of vehicles and the impact of various parameters on acceleration and speed. ...
The prediction of fatigue life and the assessment of resistance in welded structures are crucial aspects in the field of structural and mechanical engineering, especially in the design of vehicle structures. In this paper, a three-dimensional numerical model was developed using the ANSYS software to investigate the static and fatigue behavior of a simplified quarter vehicle model subjected to damped loads. Static load applied to the chassis, structure thickness, weld bead thickness, spring stiff-ness, and speed bump amplitude have a significant impact on the durability of our welded design, which represents the vehicle chassis. The objective of this study is to validate and compare the numerical results with experimental tests through parametric studies. We aim to evaluate the influence of various parameters on the reliability and durability of the welded structure. To achieve this, a scaled-down test bench was designed and constructed to measure the rigidity and durability of the structures under static and dynamic loads. The experimental results obtained align well with the developed models, exhibiting an error rate below 10%.
... 1,2 The solutions proposed for solving this issue can be found and described in many books, reports, recommendations such as Mecséri and colleagues [3][4][5][6][7] and other recent research. [8][9][10][11] Indeed, there are various operations conditions and parameters that influenced the durability of engineering structures built with welded joints. For this reason, it is very important to properly design appropriate structures under special conditions for ensuring a good performance at a large number of cycles. ...
In the present paper, a three‐dimensional numerical model has been built using ANSYS code to analyze the static and fatigue behavior of a welded design based on four rectangular profiles under damped loads for automotive application. The fatigue of the proposed design is generally influenced by a number of factors. The aim of this study is to investigate the effect of the load level, the stress ratio, the mean stress theory, the geometry size, the weld bead height, the temperature of the weld bead on the durability (P1), and the maximum of von Mises stress (P2) at the critical areas in the welded structure. As well as the length and the stiffness of the spring have been furtherly investigated. For this purpose, the application of the Taguchi method with computational simulation was performed for the target to determine the optimum operating parameters conditions. The results indicated that the optimum levels yielding a higher performance for P1 and P2 were (L1, L2, L2, L3, L1, L1, L3, and L3) and (L2, L3, L3, L3, L3, L3, L3, and L2), respectively. Thus, it revealed that the weld temperature was the predominant parameter influencing P1 and the mean stress theory factor was the most significant parameter influencing P2. This study led to defining a regression equation relating the output parameters with the selected factors. Consequently, the percentage error between regression equation calculations and computational outputs of fatigue life and maximum von Mises stress corresponding to the most optimal combinations obtained from Taguchi calculations was 0.92% and 0.63%, respectively. In fact, several parameters have been employed in this durability assessment to characterize the behavior of welded rectangular profiles prototype to predict the overall behavior of the suspension system of the automotive.
... In most cases, the necessity arises to design and analyze components with complex geometries and properties under irregular loads, then the use of existing classical methods causes finding highly complex governing equations with varied boundary and initial conditions which make it impossible to solve these equations analytically [35][36][37][38], and therefore, numerical methods should be utilized to deal with the conundrum. With respect to emersion, these are the element free method (EFM), the finite element method (FEM) [39][40][41] and the boundary element method (BEM) [42][43][44] respectively. Abundant researches are performed in the field of evaluating the parameters affecting fatigue crack growth. ...
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Adhesively bonded joints with T-shaped configurations are widely used in bonded components of engineering structures used in industries such as automotive, aircraft, and marine. In this paper, static strength and fatigue life of two T-joint configurations of flat and grooved types were evaluated. For this purpose, firstly, the effect of the specimen configuration of the bonded T-joints on the stress field has been calculated using the finite element method. For this purpose, a three-dimensional elastoplastic model is used for simulation. Then, static failure load of these joint types was examined under four loading rates of 1, 10, 50, and 100 mm/min. Also, fatigue tests were performed under maximum fatigue loads of 40%, 60% and 80% of average static failure loads. Results indicated that the average static failure load of grooved specimens was 37.3%, 26.5%, 14.4%, and 9.3% higher than that of the flat type T-joints under 1, 10, 50, and 100 mm/min loading rates, respectively. Moreover, fatigue life cycles of grooved T-joints were 40.2%, 25.3%, and 11.6% longer than that of the flat bonded specimens under 40%, 60%, and 80% maximum fatigue loads, respectively. It was also concluded that, under high fatigue loads, the groove effect can be ignored on improving the fatigue life.
... Considering the technological factors' impact on the fatigue behaviour of airframe structures is problematic even if advanced analytical methods, such as the finite-element analysis (FEA), are applied. 3,4 Additionally, when these methods are applied, creating an FE model is so complicated that its application on a real riveted structure is too expensive and time-consuming. Therefore, there are many works devoted to estimating the rivet-joint service life with analytical methods. ...
This work is focused on a quantitative procedure for estimating the generally unfavourable effects that incorrectly drilled holes, characterized by the initial clearance between a rivet and a hole, have on the fatigue life of riveted joints. The solution is based on an analytical approach using the stress-severity-factor concept. An experimental programme with riveted-joint specimens characterized by low-load transfer factors was realized in the Czech Aerospace Research Centre (VZLU) test lab under constant amplitude loading. The holes for rivet joints with 4-mm diameters were prepared with the clearance in a range of 0.0–0.16 mm. Force-controlled riveting was applied using a constant pressure force to form the driven head. To prevent fretting events between the joined parts, their anodized contact surfaces were lubricated with MOLYKA, plastic grease with molybdenum disulphide and graphite. The experimental data showed that the load-transfer factor and the fatigue life depend on the initial clearance between a rivet and a hole. The presented procedure introduced the hole-filling factor, integrated in the stress-severity-factor concept as a function of the initial clearance between a rivet and a hole.
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Riveting processes are widely used in aeronautical structures, mainly in thin shell structures, like wing and fuselage panels.
During such processes, the product shape is slightly changed. That slight geometrical change can be detected by measurement
systems or even visually in some cases. The riveting-induced shape alterations, may afect, in some amount, the aerodynamics
and the manufacturing cycle and cost of the fnal product. One cause of the deformations, among many others, is the cumulative efect of the diametral expansions, along the riveting lines. Aerodynamic surfaces, under such phenomenon, may be
sensibly afected. The consequences are not deeply addressed in the current literature. The shape problem is not considered
in the design of the riveting systems either, and the problem may be intensifed by automatic or robotized riveting systems
once those are set to accomplish an optimized cycle time, but no consideration is given regarding to the minimization of the
possible shape distortion. Such efect may become a limitation when developing manufacturing systems for high performance
wings in the aeronautical industry. In this work, one selected typical 2D airfoil section is assessed for shape deviations at the
relative proportions normally induced by riveting processes. Due to the problem complexity and to simplify this assessment,
the simulations herein are limited to 2D fow (no 3D efects addressed). The modifed airfoils are numerically evaluated in a
2D fow software code, using the panels’ method, and the results are compared with the original airfoil coefcients (Cl, Cd,
Cl/Cd). The objective of this work is to understand the overall efects produced by the shape deviations, their main contributors and the relevance to the conception of new automatic riveting systems aiming wing structural assemblies.
Keywords Riveting-induced deformations · Wing assembly · Manufacturing deviations · Riveting-growth efect ·
Aerodynamics of airfoil
The skin structure of modern aircraft is composed of frames, which are complex structures assembled by joining several sub-assemblies. One of the most used methods for joining aircraft structural parts, as well as repair patches, is through rivets. These fasteners are extensively used in the aircraft industry due to many competitive advantages.
For the load distribution, the classical method assumes that the force is distributed equally among all the rivets, but this simplification of the problem does not match reality. The riveting process has a nonlinear behaviour. This non-linearity appears from the interaction of geometry, riveting process, inelastic materials, and contact, boundary, and thermal conditions. Several previous works focused on rivet modelling have studied the impact of different factors on the riveted joint life, fatigue life, residual stress and material deformation, crack initiation and propagation, fretting fatigue, load distribution, etc. But some limited research has been carried out on the rivet distribution pattern.
In this thesis, we studied lap patches riveted to the skin structure. The analysis was done
with finite element methods using the commercial software packages Patran and Nastran. Different rivet pattern distributions were tested in order to check the rivet load distribution and the stress concentration in the plates and rivet holes. Particularly, two types of rivet patterns were used: Staggered pattern (Zig-Zag distribution of rivets) and Chain pattern (Equally distribution of rivets). The rivets and plates used in this work are made of the same material: aluminium alloy 2024-T3.
The results obtained show that the classical assumption is not appropriate. The load
distribution is not uniformly distributed. The typical tendency of the load distribution among the rivets is that the loading tends to be higher in the rivets in the corners. To reduce this load concentration, it is better to use a greater number of rows.
The direction of the applied load affects the stress distribution depending on the rivet pattern design. In the staggered configuration, if we apply a longitudinal load, the rivets suffer from a higher net stress. However, if we apply a transversal load, the net stress is nearly the same as for the non-staggered design, but the first row of rivets must sustain more stress than the subsequent rivets before they begin to share the load in this loading direction. In that design, the pattern is more important, and the distance from the rivets to the edges and the distance between the rivets must be carefully considered.
Bonded joints are widely used in industries such as automotive, wind turbine blade, and aircraft because of their ability to adhere dissimilar materials. It is significant to study manufacturing factors such as surface preparation and curing procedures in order to improve load carrying capacity and durability of the joint. In this paper, the influences of these procedures are investigated on the strength of metal-to-metal, metal-to-composite, and composite-to-composite bonded lap joints subjected to quasi-static and fatigue four-point bending tests. Sandpapering and acid-etching are selected as mechanical and chemical surface preparation methods, and three curing procedures of no post-cure, post-curing with gradual, and sudden cooling are applied. Results showed that, for similar conditions, metal-to-composite and metallic joints achieved the highest and lowest values of maximum quasi-static loads, respectively. Besides, for all joints types, mechanical surface preparation method achieved higher maximum quasi-static load and fatigue life in compare to chemical one. Maximum quasi-static load in the metal-to-composite joint showed less dependency to gradual cooling than with metallic one, and in the composite joint depends strongly to curing procedure. It is also revealed that fatigue life of the metal-to-composite joints improved for gradual cooling after post-curing. Finally, it is concluded that the metal-to-composite joints have superior quasi-static and fatigue behavior in compare with others, and the mechanical surface treatment and second curing procedure are suitable. Microscopic observations of failure surfaces showed that the metal-to-composite joints led to the cohesive failure mode which is appropriate for future repairing purposes of a bonded joint
