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The response of Fibre metal laminates (FMLs) to low-speed impact, including displacement at impact center, stress, strain response, and metal and fiber damage during the process was studied. Three types of stainless steel based FMLs with carbon fibre reinforced plastic (CFRP) specimens with different interface connections were designed and low-speed impact tests were carried out on these specimens. At the same time, finite element software ABAQUs is also used to simulate the impact process. During this process, we employ a cohesive element to characterize the bonding relationship of the interface, moreover, the influence of interface connection strength on impact resistance performance of FMLS is emphatically studied. The results show that the mechanical response and damage state of FMLS under different interface connection modes are greatly different, and the higher the connection strength, the better the overall impact resistance of the specimen. When the connection strength is poor, the specimen is easy to be separated when subjected to impact, and the metal layer suffers early damage failure, which is not ideal for the whole structure.

In view of the influence of projectile-barrel coupling on tank firing accuracy, a finite element model of projectile-barrel coupling based on vibration theory was established. By defining user subroutines to simulate the change of the physical field of interior ballistics, the load condition under which the propellant gas radial pressure acts on the inner wall of the barrel and varies with the motion of the projectile is realized. On this basis, the dynamic characteristics of projectile-barrel coupling considering the radial effect of propellant gas pressure were studied. The reference targets such as cradle, projectile and muzzle were selected for analysis, and compared with the situation without considering the radial effect of propellant gas pressure. The results show that the motion trend of the projectile in the bore and the response law of muzzle vibration change greatly when considering the radial effect of propellant gas pressure and these changes may seriously affect the law of projectile dispersion. The radial effect of propellant gas pressure can cause stronger dynamic response, which cannot be ignored in the simulation of artillery firing process. This work provides a practical reference for further study of tank firing accuracy.

Achieving high firing accuracy of tank on the move is challenging. For improving firing accuracy, better understanding launching dynamic behavior of tank firing on the move is required. This study established a rigid-flexible coupling dynamic model of tank firing on the move. Thereinto, the barrel flexibility was considered based on the FFlex body technology, and the contact-impact algorithm was used to describe the projectile-barrel interaction. With the sinusoid superposition method, a three-dimensional road surface spectrum file considering the coherence of left and right tracks was created. Based on the results obtained in simulation, this study discussed the dynamic behaviors of a tank gun system such as the barrel curvature and the influence of projectile-barrel interaction on firing accuracy of tank firing on the move, in which the factors including projectile type, driving speed and road roughness were taken into consideration. The results indicated that the barrel curvature and the muzzle vibration do not increase simply with the increase of road roughness and driving speed as common sense.

In terms of the excitation of barrel vibration on the motion modality of projectile during interior ballistic period, a finite element model considering the mutual coupling between projectile and barrel was established to study the dynamics. In consideration of the effects of propellant gas on dynamics response based on vibration theory, the real loading condition of propellant gas acting on barrel was defined by user-defined VDLOAD subroutine, which solved the problem of inaccurate loading and even the failure of loading of gases pressure in previous simulations. Simultaneously, the loading boundary condition was directed by the coupling process of powder combustion and projectile motion, modeled by the user-defined VUAMP subroutine. The dynamics responses of barrel with and without the radial effect of gas pressure were obtained. Moreover, with the aid of realization of radial loading of barrel, the influence of the deviation of mass center of barrel on its dynamics response was also investigated. The obtained results showed that the radial effect of gas pressure causes more violent dynamics responses and plays a non-negligible role in simulating artillery firing process. The dynamics response of barrel is sensitive to the deviation of mass center and the response increases with the increasing value of deviation.

This paper presents a free vibration analysis of the disc resonator gyroscope (DRG) based on the Isogeometric Analysis (IGA). The non-uniform rational B-splines (NURBS) basis functions are employed to represent both the exact geometry of DRG and displacement fields. It provides a unified process between the geometric design and analysis which significantly reduces the design cycle by eliminating the re-meshing process. Moreover, the modeling process of IGA and the numerical example of three-circle cascaded model with four different refinement schemes are presented and the computational accuracy and efficiency of the present numerical method are verified by comparing with the standard finite method (ABAQUS).

In this paper, the Isogeometric Analysis (IGA) is applied to make the modal analysis for 3D gun barrel. The geometry of IGA is modeled by None-Uniform Rational B-Splines (NURBS) which is exact and smooth even at the coarsest mesh level. The first 9 natural frequencies were calculated respectively by IGA and traditional finite element method (ABAQUS), and compared with the test results. The maximum relative error between numerical value and experimental value is less than 3.6 % which verifies the feasibility of numerical model. Six different refinement schemes were analyzed to compare the computational accuracy and efficiency of IGA and ABAQUS. To achieve the credible results, the CPU time of ABAQUS is more than twice of IGA. On this basis, the IGA method is used for the structural shape optimization of gun barrel. The first natural frequency is increased by 6.96 % and the barrel mass is reduced by 4.9 %.

Free section friction on cantilever beam is the object in this paper. Practical experiment and virtual simulation are combined to gain understanding of the whole mechanical system. The classical Tustin model cannot provide perfect description of the actual friction process. Friction compensation model 1 is established through introducing time-varying compensation into the classical Tustin model based on the classical friction model and the theory of Fourier transform. A modified genetic algorithm is proposed by introducing self-adaptive strategy. The parameter identification based on the time-varying friction compensation model is performed by using the modified genetic algorithm. Friction compensation model 2 is established by introducing the improved time-varying compensation strategies which are more in line with the friction process. The numerical results demonstrate the high iterative search capability and computation efficiency of friction compensation model 2.