As a novel riveting technology used primarily in aerospace applications, electromagnetic riveting has distinct advantages over conventional rivets in riveting difficult to form materials such as titanium alloys, the riveting of composite joint structures, the installation of interference fit fasteners, and the improvement of joint life. In this paper, the development process of electromagnetic riveting technology in China is reviewed, the characteristics of electromagnetic riveting technology are introduced, and the problems in the development and application of electromagnetic riveting technology in China are analyzed. It is believed that the application  search of the electric rivet technology and the formulation of the process specification of the electric rivet technology are urgently required. Four directions of development have been proposed in the paper: Application research of electromagnetic riveting technology, preparation of electromagnetic riveting process specifications, development of automated electromagnetic riveting systems, and application of electromagnetic riveting technology for green assembly. In conclusion, the further promotion and application of electromagnetic rivet technology is one of the necessary ways to promote aviation manufacturing technology for the realization of green assembly and intelligent assembly.

Electromagnetic riveting is a riveting technology that is driven by electromagnetic force, and driving force is the most critical factor affecting the forming quality of rivets. In order to master the influence law of driving force in electromagnetic riveting, the mathematical modeling method is used to simplify the solution process of driving force in electromagnetic riveting process, and the numerical calculation model of driving force in inductive and self-excited electromagnetic riveting is established. And the reliability of the numerical calculation model was verified by the experiment. At the same time, the MATLAB App Designer is used to design the visualization system for the calculation of the driving force of electromagnetic riveting, and the simple and convenient calculation of the driving force of electromagnetic riveting is realized. Based on this system, the influence law of the electrical parameters of the self-excited electromagnetic riveting is analyzed. The results show that the increase of discharge voltage and capacitance, and the decrease of loop resistance and loop inductance are beneficial to improve the peak value and change rate of the electromagnetic driving force of electromagnetic riveting.

The research on dynamic mechanical behavior and related failure mechanism of new aerospace structural materials, represented by light metal and composites, under the intermediate strain rate environment has attracted more and more attention. To fully explore the corresponding relationship between the performance of new structural materials and strain rates, a novel experimental system that can achieve dynamic tensile testing at medium strain rates has been developed based on the electromagnetic riveting system. This provides a scientific and efficient experimental method for dynamic performance testing of metal and composite materials and their joining structures. The article first introduces the basic principle and functional characteristics of the electromagnetic loading device, and then provides a detailed explanation of the loading system, control system, and data acquisition system; The following mainly introduces the changes in corresponding mechanical responses under different parameters during the dynamic loading test process and the consistent results under repeated tests, thereby verifying the stability and reliability of the entire experimental system; Finally, the mechanical properties of 2024–T6 aluminum alloy under different strain rates were tested using this system. The results of this research show that the electromagnetic loading dynamic tensile testing system can accurately reflect the effect of strain rate changes on the performance of 2024–T6 aluminum alloy, providing strong technical support for the structural safety research of new aviation materials in service environments.

Electromagnetic riveting can solve the riveting problems of large-diameter and difficult-to-form materials. Compared with pneumatic riveting gun, generally the electromagnetic riveting gun with larger volume was only used for riveting in open structures due to the addition of damping system. Therefore, the development of electromagnetic riveting gun integrated with riveting gun and support iron operated by single person aimed at solving the problem that the application of riveting gun was limited in non-open structures. Firstly, this paper explained the operating principle of electromagnetic riveting, and then introduced the structural design of riveting gun including support iron, clamping system, damping system, and cooling system, as well as analyzed the strength and stiffness of the support iron through finite element simulation analysis. Finally, its riveting ability and the riveting force of titanium-niobium rivet of electromagnetic riveting were both tested. It was concluded that the riveting gun can generate as a Φ4 mm titanium-niobium rivet with good repeatability of header size, and the structural strength of the riveting gun is also safe and reliable.

To study the processability of electromagnetic riveting technology, we explored the feasibility of manually operated electromagnetic riveting by experiments, and analyzed riveting quality through the analysis of rivet formation, the interferences between rivet and hole, as well as the damage of composites. The results show that it may be not easy for operators to hold the riveting gun and top iron stably due to the instantaneous impact force of electromagnetic riveting. Compared with pneumatic hammer riveting, the impact force of electromagnetic riveting increased the muscular load of the operator’s arm by about 50%. In addition, on composite-titanium alloy and composite-composite structures, the size of the titanium-niobium rivet upset head met process requirements without obvious cracks. In addition to no damage observed inside the composite, reliable interference fit can be formed between the nails and holes. However, the problems of skewed heading and small inclined edges of the heading limit the application of electromagnetic riveting.

A dynamic insertion (DI) method of CFRP interference fit bolts based on an electromagnetic riveter was developed to improve the quality of bolt-hole contact interface and enhance the bearing capacity of the joints. The experiments were conducted to investigate the insertion process for the DI method, and the corresponding static insertion (SI) method was also investigated as comparison. The insertion force-displacement response during the interference fit bolt insertion process was measured. The effects of the insertion method and the interference fit sizes on the insertion damage of the laminate were evaluated from macroscopic and microscopic perspectives. Moreover, the quasi-static tensile properties of joints after DI and SI were compared, the effect of DI method on the joint properties was assessed, and the mechanism of the DI method in joint performance improvement was initially discussed. Results show that DI method can significantly reduce the interference fit insertion resistance compared to SI method, and the larger the interference size the larger the reduction ratio. Furthermore, the DI method improves the quality of the bolt-hole contact interface. In static tensile test, the DI specimens exhibited higher ultimate strength and joint stiffness than the SI specimens.

Electromagnetic riveting (EMR) technology can effectively form large-diameter rivets in a single process and quickly produce high-quality joints. It has broad application scenarios in the aerospace industry, but there are few studies related to EMR joints for large-diameter steel rivets. In this paper, an EMR platform for large diameter rivets was built, and the riveting process test was carried out for 10 mm diameter steel rivets. The results show that the header diameter increased with increasing discharge energy and the header height decreased with increasing discharge energy. At the same discharge energy, the larger the preformed hole diameter, the smaller the header height and the larger the header diameter. In addition, the interference fit size of riveted joints gradually increased with the increase of discharge energy for both prefabricated hole diameters. The interference fit size of riveted joint with the prefabricated hole diameter 10.1 mm was always greater than that with 10.3 mm. At the same time, the value (10.3 mm) was not suitable as the preferred process parameter because the riveted joint with the prefabricated hole diameter 10.3 mm tended to be skewed during the riveting process. In addition, the optimal process parameters were obtained by combining the discharge energy: the prefabricated hole diameter of 10.1 mm and the discharge energy of 15.5 kJ. Finally, the interference fit size and mechanical properties of the EMR joints were compared with those of the conventional hydraulic riveted joints. The results indicated that the interference fit size (2.15%) of the EMR joint prepared according to the optimal process parameters was larger and more uniform than that of the hydraulic riveted joint (1.75%). The maximum shear load and energy absorption values were slightly higher than those of the hydraulic riveted joint.

Dual-beam laser welding of titanium alloys for aircraft wall panels has gradually become the main connection method for high-performance fuselage structures. In view of the high requirements of wall panel welds, variety of defects, and large-scale welds, there is an urgent need for a non-destructive testing technology that takes into account the characteristics of high efficiency and high precision to ensure its safety performance. The high-frequency ultrasonic phased array inspection technology for the welding seam of aircraft wall panels is proposed in the research. The phased array ultrasonic inspection probe and the contrast test block are designed to perform fan-scan imaging detection of the internal and external defects of the weld seam, and then， the detection is verified by the metallographic method result. The research results show that the high-frequency ultrasonic phased array inspection technology can effectively detect the typical internal and external defects in the wall T–weld seam, including: non-fusion, pores, undercut, poor weld formation. The advantages of high efficiency, high precision, intuitive and reliable characteristics, make it suitable for non-destructive testing of aircraft wall welds.

The carburized layer at 18Cr2Ni4WA steel gear root has mechanical behavior different from the substrate. Its accurate characterization is important for the analysis on the crack initiation and fatigue properties of the gear root. The nano-indentation test is taken as the test measure for the characterization of the local mechanical behavior in the carburized layer. Nano-indentation tests are carried out within the carburized layer. The finite element simulations of nano-indentation tests with different sets of constitutive model parameters combination are performed. Based on the simulated and the experimental load-displacement curves, the combined prediction errors of curvature, residual depth and the ratio of plastic deformation work to total deformation work are calculated. In result, the constitutive model parameters are defined for the carburized layer. It is verified that the constitutive model derived by this method can reflect the mechanical behavior of the
carburized layer.

The measurement and compensation of volumetric error is an important means to improve the machining accuracy of machine tools. A measurement method based on a laser Doppler displacement meter is used to identify the geometric error elements of the machine tool. Then, based on the theory of homogeneous coordinate transformation, the volumetric error model of the vertical machining center is established. And use offline modification of G code to implement machine tool volumetric error compensation. Compared with the laser interferometer multiline method, the method of sequential step diagonal is simpler and faster, and 12 key geometric errors can be quickly obtained through 4 tests. The results of error test and compensation show that the overall accuracy level of machining center has been greatly improved, and the body diagonal error has been reduced to 32.5%.

Aiming at the problems of low efficiency, poor uniformity, and poor consistency of the existing burr removal process for the intersecting-hole parts top shell in the servo mechanism, a suggestion of using the abrasive flow deburring process was proposed. Through the analysis of the internal structure of the workpiece and the planning of the deburring processing path, the runner simulation model of each processing path was established, and the flow field characteristics of the corresponding path of each inlet runner group were compared, analyzed and optimized for better process path. Deburring verification experiments were carried out on the top shell workpiece. The results show that the uneven distribution of the streamline inside the flow channel and the large difference in the streamline pressure can be effectively improved by increasing the drainage section structure at the exit of the large hole and extending the length of the flow channel. Finally, the problem of inconsistent burr removal effect during processing can be solved and the sharp edges at the entrance and exit can also be effectively protected. After the experiment, the internal burrs of the runner are removed, and the edges of the internal small holes are rounded, which improves the surface quality and performance of the workpiece.

Rare earth Y has excellent refining effect on TiB₂ particle reinforced composites, and can improve the performance damage caused by TiB₂ particle clusters. It plays an important role in improving the comprehensive mechanical properties of composites. In this paper, 3% (mass fraction) TiB₂/Al–Zn–Mg–Cu–Zr–Y composite plates were prepared by traditional casting and hot extrusion. The effects of Y content on the microstructure and mechanical properties of TiB₂–reinforced aluminum matrix composites were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and tensile test at room temperature. The results show that the as-cast microstructure of composites can be refined by addition of Y, and the refining effect is the best when 0.1% Y (mass fraction) is added. The composite with 0.1% Y (mass fraction) has the best mechanical properties, with the ultimate tensile strength (UTS) of 729.85 MPa and the elongation (EL) of 8.06%. The addition of Y element leads to the formation of insoluble phase Al₈Cu₄Y(Zr) at the grain boundary, which can be broken and strengthened by hot extrusion. Excessive Al₈Cu₄Y(Zr) leads to the decrease of strength and plasticity of the material. TiB₂ particles can increase the dislocation density in the matrix, and have the effect of dislocation strengthening and load transfer strengthening. GP II and η′ are the main nano-strengthening phases in the T6 state of the composites.

According to the performance parameters and structure position of the design target, the initial value of the gun is obtained by the comprehensive iteration method. Moreover, the performance of tungsten and LaB6 cathode materials was compared, the appropriate cathode materials were selected, and the 60 kV space electron gun was simulated by using the SOURCES related procedures, and the simulation results such as coefficient of chromatic aberration and beam spot diameter were obtained. According to the focal length formula, the focal length of the first-order focusing system is obtained and the simulation results of the focusing system, such as focal length, beam spot and optical path diagram, are obtained. By analyzing the shortcomings of the first stage focusing system, the second stage focusing system is redesigned, and the performance parameters such as pole shoe hole diameter, coil excitation and the distribution map of the electromagnetic lens axis are obtained by simulation. Finally, the parameters of electron gun and electron optics are obtained according to the simulation results of two-stage focusing system.