Tool Bits with Elastic Damping Inserted Elements Formed by Semi-Inserts with Different Rigidity

Vibration during turning is a consequence of premature tool wear and an increase in the roughness of parts. The designs of tool bits that increase their durability, reduce vibrations arising during the cutting process, and improve the quality of processing are of practical and scientific interest. Existing developments of vibration-damping bits with elastic damping inserts of constant rigidity, in which a holder or mandrel with a cut-off insert is installed, do not meet the requirements for the efficiency of vibration reduction due to the impossibility of the necessary vibration damping; the consumption of insert materials is high. Innovative designs of tool bits with inserts formed by semi-inserts with different rigidity are proposed, which allows improving the quality of processing by increasing the efficiency of vibration damping, reducing material consumption, because the length of the semi-inserts is less than half the length of the full insert. The tool bits can be used in the area of cutting materials, mechanical engineering and tool manufacturing.

Active control of a sandwich plate with reinforced magnetostrictive faces and viscoelastic core, resting on elastic foundation

The current study presents a vibration investigation of a laminated plate considering a viscoelastic core with embedded magnetostrictive layers. The simply-supported plate is supported via Pasternak’s substrate medium. Based on different plate theories and employing Hamilton’s principle, the system of governing differential equations is derived. The mechanical properties of the viscoelastic core are described depend on the time varies based on Kelvin–Voigt model. Actuating magnetostrictive layers are utilized to control the vibration damping process of the system with the assistance of feedback and constant gain distributed control. The analytical solution is obtained to investigate the influence of half wave numbers, thickness ratios, core thickness, aspect ratios, lamination schemes, elastic foundation parameters, damping coefficient, feedback coefficient magnitude, magnetostrictive layers location, on the vibrational behavior of laminated plate. Some observations about the vibration damping process of the present plate are displayed. The results refer to that the vibration suppression rate depends on the thickness of the plate, the feedback control value, the foundation constants, and the viscoelastic structural damping significantly. Moreover, the study can be providing benchmark tests to validate future contributions on the viscoelastic smart structural issues and developing the design of smart viscoelastic structures and control of their vibrations.

Research on Railway Engineering Experiment Teaching Principles Based on Virtual Simulation Experiment Teaching——Taking the Floating Slab Vibration Damping Track Virtual Experiment as an Example

Virtual simulation teaching is an addendum to the experimental teaching mode of railway engineering, and the two teaching methods complement each other and merge with each other. In view of the current research, there is little discussion about the integration path of the two above. Based on the connotation and design of virtual simulation teaching, this research systematically expounds the integration of the real path and path optimization problems, and puts forward the railway engineering experimental teaching principles based on virtual simulation teaching. On the basis of this research, a virtual simulation experiment platform for vibration mechanics and its application in the floating slab vibration damping track was developed to make full use of three-dimensional modeling, virtual reality, human-computer interaction and other technologies, which can realistically simulate the vibration law and vibration damping effect of the rail transit system, and in the hope that the virtual simulation teaching can be widely used in the experimental teaching mode of railway engineering in the future.

Development of spring torsion bar type negative stiffness damping device and applied research

Mini-tiller is the most commonly used machine for agricultural production in hilly areas of our country the traditional micro-tiller will produce strong vibration during the working process, which will cause physical injury to the operator while reducing the reliability of the micro-tiller. In response to this problem, a technical solution for arranging a spring torsion bar type negative stiffness vibration damping device on the tiller was proposed, and a spring torsion bar type vibration damping device with stable mechanical performance, economical and practical, and negative stiffness characteristics was developed. A mathematical model of the vibration source of the micro-tiller was established to analyze the vibration parameters of the micro-tiller. On this basis, SolidWorks is used to carry out three-dimensional modeling of the tiller and the vibration reduction device, and Adams is used for vibration simulation analysis. The vibration parameter curve before and after the addition of the vibration reduction device at the handle of the tiller is collected and mathematically analyzed. The results show that the spring torsion bar type negative stiffness damping device has a good damping effect, and the damping rate for displacement in the x, y, and z directions are all above 30%.