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Copyright of Journal of Beijing University of Technology is the property of Journal of Beijing University of Technology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Slug rivet interference-fit riveting is an advanced connection technology. The quality of riveted aircraft structures can be evolved to a higher-level with good sealing performance when using slug rivet. Some research has been conducted to study the effects of riveting process on riveting quality. But, few attentions have been paid on the action mechanism of rivet die structure during riveting process. This paper reveals the internal relation between rivet die structure and riveting quality in the forms of theoretical and numerical analyses as well as experimental verification. Three typical concave rivet die structures and the corresponding combinations have been studied. The result indicates that well-designed rivet die can effectively improve riveting quality. The rivet die with isosceles trapezoid cross-section can generate a larger radial reactive force to prevent the radial flow of rivet metal material to form driven head. More axial material flow can be pushed into rivet hole to increase the interference value. The results considerably improve knowledge about the behavior of rivet die during riveting process. The aim is to find out the appropriate rivet die to improve riveting quality. The study will pave the way for high structural fatigue-resistant design in modern aerospace manufacture. [ABSTRACT FROM AUTHOR]

The humanitarian damage caused by the unexploded submunitions is one of the hot issues of concern to the international community at present. A portion of the submunition that did not explode was caused by a break at the connection between the ribbon riveting and the fuze. According to the physical structure of the submunition and the trajectory into which it was ejected, we analyzed the forces of the submunition in flight, deduced the related mathematical models, and clarify the key elements of the mechanics. In this paper, the commercial simulation software was used to calculate the mechanical properties of the ribbon. And the variation regularity between drop velocity and straightening force of ribbon are revealed. And the response characteristics of different material ribbon with different sizes of riveting holes and riveting joints under tensile action were simulated. The simulation results show that, in the trajectory environment with 30 m/s~55 m/s typical stream speed, the tensile force of the ribbon is less than 300 N, and the application concentration of the connecting parts of the riveting joint and the ribbon will not cause the failure of the kevlar ribbon, but it will cause the failure of the nylon ribbon. In order to verify the variation of the tension of kevlar ribbons in different trajectory environments, we designed the experimental scheme of tension test of the ribbon straightening section of submunition and conducted experiments. Experimental results and numerical simulation results revealed the same law. This paper provides effective technical support for solving the problem of unexploded submunitions. [ABSTRACT FROM AUTHOR]

To facilitate the die selection for new self-piercing riveting (SPR) joint configurations, it is necessary to find out how the critical die geometric parameters influence the SPR process. In this study, a two-dimensional (2D) axisymmetric simulation model was developed to numerically study the riveting process. The influences of the die type, the die diameter, the die depth, and the die pip height on the deformation behaviour of the rivet and sheets were systematically studied. Moreover, the flared rivet shank radius and the thickness at the centre of the bottom sheet during the SPR process were first monitored using the developed simulation model. The simulation results revealed that these die parameters have significant influences on the deformation behaviour of the rivet and sheets. The flared rivet shank radius showed an increasing trend with the increment of the die diameter and the die pip height, while it decreased with the increment of the die depth. Furthermore, it was also found that the flaring speed of the rivet shank depended heavily on the filling condition of the die cavity underneath the rivet cavity. A rapid flare of the rivet shank was observed when this space was fully filled. [ABSTRACT FROM AUTHOR]

This work measures the contact area between an anti-rotation rivet and an aluminum plate under different riveting loads based on the regional scanning of ultrasound. The contact image is a novel disclosure for the anti-rotation rivet contact. The 2D maps show an apparent change not only in area sizes but also in contact shapes under various normal forces applied. The 3D contact images also provide useful information to show the intensity of contact. The contact area between the anti-rotation rivet and the aluminum is calculated using an image analysis software package. The range of contact areas varies from 6.3 mm² to 57.2 mm², depending on the applied forces and the definition of the contrast ratio. Furthermore, a calibration of data fitting is performed to provide a useful polynomial equation for contact area estimation. In addition, maps of both a reflection coefficient and a pressure contour distribution are presented. The range of peak contact pressure varies from 7.1 MPa to 11.2 MPa. [ABSTRACT FROM AUTHOR]

The Sobolev embedding theorem implies correct formulation of the Dirichlet condition at isolated points or transmission conditions that simulate contact welding, bolt or screw fastening, etc. The problems on bending the Kirchhoff plate with periodically distributed point supports and the joint of two plates by rows of rivets are considered. The asymptotic analysis performed provides asymptotic expansions of solutions and error estimates, namely, the one-dimensional model of a narrow plate and the transmission conditions at the common boundary of two plates. The results of homogenization differ seriously in the cases of one or several rows of supports and rivets. In particular, one-row riveting provides only a hinge joint of plates (discontinuities in the rotation angle are allowed), but two-row riveting provides an almost complete clutch at which all elastic fields become, in main, continuous at the common edge. [ABSTRACT FROM AUTHOR]

To this day, most of the papers related to hybrid joints were focused on single and double lap joints in which shear deformation and degradation was the dominant phenomenon. However, in real constructions, complex state of loads can be created by: a) torsion with shear, b) bending with shear, c) torsion with tensile. Analytical and numerical computation for simple mechanical joints is known, however, the introduction of an adhesive layer to this joint makes the load transferred both through: (1) the adhesive and (2) mechanical fasteners. There is also an interaction between the amount and stiffness of mechanical fasteners and the strength of the adhesive layer. The paper presents the results of numerical calculations for the bending with shear type of load for the hybrid structural joint and corresponding simple joints by: (1) pure adhesion and (2) rivets with different quantity maintaining the same cross-sectional area. A total of 9 simulations were performed for: (1) 4 types of pure rivets connections, (2) pure adhesive joint and (3) 4 kinds of hybrid joints. The surface-based cohesive behavior was used for creation of the adhesive layer, whereas the rivets were modelled by connector type fasteners, which simplify complexity of the numerical model. The use of connectors allowed for effort assessment taking into account damage in both types of connections. Application of connector elements can be useful for larger structures modelling, e.g. aircraft fuselage, where the number of mechanical joints is significant and complex load conditions occur. [ABSTRACT FROM AUTHOR]

Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

It is difficult to adapt to the actual situation of the production and testing of the rivets by examining the defects of low working efficiency and low accuracy. In order to solve this defect, through a series of research and analysis, it can be found that the non-contact automatic inspection method can solve the existing defects. The OSTU operation method is improved and used for the image segmentation of the rivets, which can reduce the error segmentation. In order to eliminate the uncertainty of the rivet position, the method of the least external rectangle method is obtained to determine the main shaft of the rivet. This approach reduces randomness at work. Through the study of rivet contour curvature method to analyze the characteristics of the part of the rivet contour, can better reduce in proportion of noise in the process of operation, and has a lot of improvement for accurate precision. Through experiment that this method of testing with high accuracy, errors generated during inspection situation is less, and less affected when testing can improve the efficiency of detection in industrial production, can well meet the demands of rivet real-time inspection. [ABSTRACT FROM AUTHOR]

A new walking riveting robot integrating hole making and riveting based on 6-SPU six degrees of freedom parallel mechanism was analyzed statically. On the basis of inverse position modeling and solution, the correct position of riveting hole of riveting gun was determined according to robot riveting trajectory planning. For aircraft large thin-walled cylindrical workpiece, the finite element analysis software was used to simulate the robot riveting operation, and the maximum deformation of the moving platform and the maximum equivalent stress of the mechanism were obtained. The simulation results showed that the maximum deformation of the robot was 51.847 X 10-7 m, which was within the allowable error range of aircraft riveting hole making, and the maximum equivalent stress of the mechanism was 2.698 MPa, which was far less than the material yield limit, which could meet the requirements of precision and strength of riveting hole operation. [ABSTRACT FROM AUTHOR]

Eddy current methods are commonly used in the inspection of riveted multilayer structures. In a practical scenario, steel rivets may be magnetized to varying levels which can distort the magnetic field and pose a major challenge since the distortion can result in false positives and negatives. This paper presents an invariance transformation procedure that renders the signal insensitive to changes in magnetization while retaining the sensitivity to defect information. The approach is first implemented on simulated data, where the signals from magnetized steel rivets can be generated under controlled variation of relative permeability. The algorithm is then validated on experimental data acquired using steel rivets with different residual magnetization levels. [ABSTRACT FROM AUTHOR]

Slug rivet interference-fit riveting is one of the advanced connection technologies. Many researches have been conducted to study the quality of slug rivet assembly. However, some previous theoretical studies have only focused on the riveted lap joints without countersunk hole structure. To make a more comprehensive understanding of the riveting quality, this paper first proposes an effective method to study the riveted assembly with countersunk hole structure. An effective and accurate theoretical model is built to reflect the mapping relationship between squeezing force and driven head dimension. Since the driven head dimension is the riveting quality control criterion, and the squeezing force is the most important riveting parameter. Simulations and experiments are conducted to verify the validity of the theoretical analysis. Comparison results prove the theoretical model's ability to analyze the rivet deformation. Theoretical analysis can provide an effective compact analysis. The study will pave the way for further investigations. [ABSTRACT FROM AUTHOR]

Copyright of Muiraquitã: Revista de Letras e Humanidades is the property of Muiraquita and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article presents a comparative investigation on mechanical behavior and construction characteristics of some typical connections in cold-formed thin-walled steel. The lap shear tests of 96 specimens considering four typical connections with a self-piercing rivet, clinching, self-drilling screw, and blind rivet were conducted. The effects of sheet thickness and thickness ratio on failure modes and mechanical behavior of the four types of connections were investigated. Through analyzing the feasibility of mechanic and construction, the applicability of the four types of connections in fabricated cold-formed steel structures was comprehensively evaluated. The result of the research shows that compared with the other three connections, self-piercing rivet connections are more suitable for modularly fabricated cold-formed steel structures because of its superior mechanical properties, well-formed quality, high efficiency, and potential industrialization. Based on the design methods of fasteners in North American (AISI S100-16) and European standards (prEN1999-1-4) on cold-formed steel structures, an appropriate design method is proposed for self-piercing riveting connections. [ABSTRACT FROM AUTHOR]

Featured Application: On-machine optical measuring process of through-hole depth for automatic drilling and riveting system. In the aerospace manufacturing industry, it is impossible to achieve precise and efficient automatic drilling and riveting for largescale composite board parts. The bottleneck is that the depth detection of rivet holes still relies on manual operation, which seriously affects the assembly efficiency and stability of composite board parts. In order to realize accurate and efficient on-machine automatic measurement for through holes in the automatic drilling and riveting process of largescale composite board parts, this paper presents a novel hole depth measuring device. Its mechanical structure is developed based on our newly designed measurement scheme and optical path, the purpose of which is to convert the hole depth data into displacement data of the probe motion. Its electrical hardware consists of three units: a laser transceiver unit to pick up laser spots; a displacement measuring unit to capture the probe movement in real time; and a driving unit to achieve motion control of the probe. Finally, the experimental results indicated that the proposed method and device are capable of performing automatic measurements for through-hole depth. In addition, factors affecting the measuring accuracy and stability of the device are initially analyzed and discussed, which lay a foundation for subsequent research on error compensation and probe calibration. [ABSTRACT FROM AUTHOR]

An attempt is made to analyse the performance of an external gate feeder for headed parts (rivets, bolts, etc.). A model is developed to study the effect of different parameters on its performance. The feeder was fabricated and its performance was studied to verify the proposed model. The model covers a wide range of working. [ABSTRACT FROM AUTHOR]

In this study, the effects of thermal fatigue loading on the riveted structures made of 2014, 2024, 6061 and 7075 aluminum alloys which are widely used in the aviation industry have been investigated. An algorithm has been developed under ANSYS finite element analysis software to determine the behavior of these structures that are exposed repeated thermal loading. This algorithm is based on the principle of determining the distribution of the safety factor on the material subjected to the thermal fatigue load. In the study, the rivet spacing (RS), the rivet edge distance (ED) and the rivet hole diameter (RD) were selected as riveting parameters. It is aimed to determine the optimum values of the parameters used under thermal fatigue loading and the most suitable one for this loading among the materials used. It is seen that 7075 aluminum alloy has the highest safety factor distribution for all the models in which the effect of these parameters was investigated. It has been determined that when the rivet spacing is 3 times the rivet diameter (3d), the highest safety factor value is obtained for all material types. And this value decreases when the rivet spacing is increased. When the effect of the rivet edge distance is examined, it is seen that when the rivet edge distance 8d is used, the highest safety factor value is obtained. The safety factor value is the smallest when the rivet edge distance is 2,5d. In addition, when rivet hole diameter increased from 2.5 mm to 4.8 mm, it was determined that safety factor value increased. [ABSTRACT FROM AUTHOR]