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During the design of automotive structures assembled using Self-Piercing Rivets (SPRs), a rivet and die combination is selected for each joint stack. To conduct extensive physical tensile testing on every joint combination to determine the range of strength achieved by each rivet–die combination, a great deal of lab technician time and substrate material are required. It is much simpler and less material-consuming to select the rivet and die solution by examining the cross sections of joints. However, the current methods of measuring cross sections by measuring the amount of mechanical interlock in a linear X–Y direction, achieved with the flared rivet tail, do not give an accurate prediction of joint strength, because they do not measure the full amount of material that must be defeated to pull the rivet tail out of the bottom sheet. The X–Y linear interlock measurement approach also makes it difficult to rapidly rank joint solutions, as it creates two values for each cross section rather than a single value. This study investigates an innovative new measurement method developed by the authors called Volumelock. The approach measures the volume of material that must be defeated to pull out the rivet. Creating a single measurement value for each rivet–die combination makes it much easier to compare different rivet and die solutions; to identify solutions that work well across a number of different stacks; to aid the grouping of stacks on one setter for low-volume line; and to select the strongest solutions for a high-volume line where only one or two different stacks are made by each setter. The joint stack results in this paper indicate that there is a good predictive relationship between the new Volumelock method and peel strength, measured by physical cross-tension testing. In this study, the Volumelock approach predicted the peel strength within a 5% error margin.

This study explores the tensile performance of blind rivet joints in galvanized steel sheets, focusing on their behavior under shear and normal load conditions. Blind rivets are frequently used in structural applications due to their ease of installation and ability to be applied from one side, making them highly effective in industries like aerospace and automotive. Two types of DIN 7337—4.8 × 8 blind rivets—galvanized steel St/St and stainless steel A2/A2—paired with galvanized steel sheets DX51D + Z275, were experimentally tested to assess how their material properties affect their joint strength, deformation patterns, and failure modes. Single-lap shear, double-lap shear, and pure normal load tests were conducted in multiple configurations to evaluate joint performance under varying loading conditions, simulating real-world stresses. Using custom-built equipment, controlled forces were applied perpendicular to the rivet joints to replicate practical loading conditions. The results revealed distinct differences in the load-bearing capacities of the two materials, offering valuable insights for applications where corrosion resistance and structural integrity are critical. Finite element analysis (FEA) was then used to simulate the behavior of the joints, with the results validated against experimental data. To enhance the reliability of numerical simulations in optimizing the design of rivet joints, a methodology was proposed to calibrate non-linear FEA models to experimental results, and a substantial agreement of 92.53% was achieved via optimization in ANSYS OptiSLang. This research contributes to our broader understanding of riveted connections, providing practical recommendations for assessing the performance of such joints in various engineering fields.

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.

For the sake of improving the static mechanical properties and decreasing the exterior protrusion height of the clinched joint, a mechanical rivet-reinforcing process with different reinforcing loads was carried out to join AA5052 sheets in this study. Tubular rivets with 1 mm wall thickness were used to conduct the rivet-reinforcing experiment. The static strength, failure mode, neck thickness, interlock value and energy absorption of the rivet-reinforced joints realized with different reinforcing loads were comprehensively analyzed by experimental method. With the gradual increase of the reinforcing load, the interlock value and neck thickness were enlarged, while the height of exterior protrusion was decreased. When the reinforcing load was 45 kN, the height of exterior protrusion was decreased from 1.17 to 0.52 mm. The energy absorption and average static strength of dissimilar rivet-reinforced joints were significantly higher than that of the conventional clinched joints. The average strength was increased from 1835.23 to 4032.87 N in the single-lap-shear test, and from 1395.02 to 1658.99 N in the cross-lap-tensile test. The energy absorption of joint was increased from 1.34 to 6.77 J in the single-lap-shear test, and from 4.26 to 9.18 J in the cross-lap-tensile test. It was proved that rivet-reinforcing process with tubular rivet can effectively increase the mechanical properties of the conventional clinched joints.

Drilling is considered as one of the most challenging problems in aerospace structures where stringent tolerances are required for fasteners such as rivets and bolts to join the mating parts for final assembly. Fiber-reinforced polymers are widely used in aeronautical applications due to their superior properties. One of the major challenges in machining such polymers is the poor drilled-hole quality which reduces the strength of the composite and leads to part rejection at the assembly stage. In addition, rapid tool wear due to the abrasive nature of composites requires frequent tool change which results in high tooling and machining costs. This review intended to give in-depth details on the progress of drilling of fiber-reinforced polymers with special attention given to carbon fiber–reinforced polymers. The objective is to give a comprehensive understanding of the role of drilling parameters and composite properties on the drilling-induced damage in machined holes. Additionally, the review examines the drilling process parameters and its optimization techniques, and the effects of dust particles on human health during the machining process. This review will provide scientific and industrial communities with advantages and disadvantages through better drilled-hole quality inspection.

In today’s digital world, the Internet is an essential component of communication networks. It provides a platform for quickly exchanging information among communicating parties. There is a risk of unauthorized persons gaining access to our sensitive information while it is being transmitted. Cryptography is one of the most effective and efficient strategies for protecting our data and it are utilized all around the world. The efficiency of a cryptography algorithm is determined by a number of parameters, one of which is the length of the key. For cryptography, key (public/private) is an essential part. To provide robust security, RSA takes larger key size. If we use larger key size, the processing performance will be slowed. As a result, processing speed will decrease and memory consumption will increase. Due to this, cryptographic algorithms with smaller key size and higher security are becoming more popular. Out of the cryptographic algorithms, Elliptic Curve Cryptography (ECC) provides equivalent level of safety which RSA provides, but it takes smaller key size. On the basis of key size, our work focused on, studied, and compared the efficacy in terms of security among the well-known public key cryptography algorithms, namely ECC (Elliptic Curve Cryptography) and RSA (Rivets Shamir Adelman).

PurposeIn order to improve the rationality of the design of carbon fiber composite riveting structures in engineering products and reduce physical tests, the stress changes of various parts during the carbon fiber-reinforced polymer (CFRP) riveting process, the influence area of hole edge stress and the damage of CFRP plates were studied from the perspective of numerical simulation. The reasonable arrangement requirements of composite riveted structures, installation speed and damage characteristics of CFRP plates in engineering applications are obtained. The research results provide technical references for the design and installation of composite riveting structures in engineering products.Design/methodology/approachTaking the forming process of the riveted structure between countersunk blind rivets and CFRP plates as the research object, the forming principle of countersunk blind rivets and the damage characteristics of CFRP plates were analyzed. Using contact nonlinearity theory, the anisotropic material modeling method and the Hashin failure criterion, the stress changes in various parts during the riveted joint forming process, the influence area of stress at the hole edge of the rivet holes and the damage of the CFRP plates were analyzed.FindingsReasonable rivet layout spacing was obtained; the peak stress of the rivet assembly increases with the increase of the rivet installation speed, and the influence area of the hole edge on the CFRP plate is a circular area with an outward extension radius of 0∼6 mm. Therefore, the arrangement distance between rivets is greater than the ring area, the damage law and installation speed of CFRP plates are given, the damage extends inward from the first layer of the laminates and the installation speed of 15 mm/s can satisfy the requirement of riveting installation better.Originality/valueThe riveting and forming process under different speeds is analyzed from the perspective of numerical simulation, and the stress variation rule of each part of the rivet and the damage of the CFRP plate under each speed are obtained. Reasonable rivet arrangement requirements and installation speed were given. This study provides technical support for the rivet arrangement method and mechanical property analysis of CFRP riveted structures in complex engineering products.

An important factor having a negative impact on the technical condition of aircraft structure elements is the adverse effect of the atmosphere, which causes formation of corrosion in aircraft structures, especially in riveted lap joints. The electric potential difference between the sheet material and the rivet, in the presence of humid air, may cause electrochemical corrosion. The paper presents specimens that imitate the repair on the Mi-24 helicopter with the use of blind rivets in places where solid double-sided rivets could not be used. The aim of the research was to assess the corrosion resistance of lap joints with the use of single-sided and double-sided rivets. The analysis of corrosion resistance was carried out based on accelerated aging tests in a salt spray chamber. The salt chamber tests were aimed at determining the changes taking place in the specimens exposed to the marine environment. In the course of periodic observations changes in the mass of the specimens and in the form of corrosion losses were recorded. These activities were aimed at determining whether the exposure of specimens in the salt chamber causes electrochemical corrosion or pillowing. In addition, the specimens were subjected to static strength tests to assess the effect of corrosion on the strength properties of riveted joints.

This study focuses on the rivet early fatigue characteristics in a deep-groove ball bearing cage for a transmission system in a turboprop engine. Nonlinear dynamic differential equations for the deep-groove ball bearing with a two-piece cage were developed. The rivet stress was used to identify the early failure mechanism of the rivets. This investigation revealed that by delivering an optimal preload of the rivet causes the two halves of the cage have less misalignment and a lower rivet stress. The fit relationship between the rivet and the rivet bore has a significant influence on the rivet stress. Excessive clearance increases the stress on the head of the rivet, while excessive interference increases the stress on the middle of the rivet. For the 1.5 mm diameter rivet analyzed in this study, the appropriate fit relationship is −0.02 mm–0 mm. A reasonable matching value of the load and the speed and the cage clearance ratio are beneficial to reducing the rivet stress. The impact load acting on the bearing and a ring misalignment can increase the rivet stress.

Within the double-sided countersunk riveting process of aircraft wings with a composite wedge structure, riveting consistency is poor, and composite damage is severe, which seriously affects the performance and reliability of the aircraft structure. This paper used the principal stress method to establish a stress model of countersunk riveting, and, based on the analysis of the stress on the structure during the pressure-riveting process, a composite structure rivet was designed. A finite element simulation model of the double-sided countersunk riveting of composite wedge structures’ composite rivets was established. The influences of the structure and the matching parameters of composite rivets on both the plastic flow of pressure riveting and the compressive stress of the structure during the pressure-riveting process were analyzed. The structural parameters and riveting process of composite rivets were optimized. The results show that the composite rivet structure could significantly reduce the contact-compressive stress at the riveting joint by more than 20%, thereby reducing the damage caused by the riveting to the composite material. For 4 mm rivets, an aperture of 4.04~4.06 mm can achieve precise relative interference riveting at 0.6% to 1.0%. Employing a 2.6 mm rivet elongation can exactly fill the countersunk hole of the wedge.