Optimization of a Suspension of a Micromechanical Accelerometer in an Angular Velocity Measurement Unit

Optimization of the suspension of the micromechanical accelerometer, which is a part of an angular velocity measurement unit, was considered. This problem was faced because of the need to improve the design of the existing device to meet new technical requirements. Shock loads up to 1 000 g exceed ultimate loads for micromechanical accelerometers by several orders of magnitude. During the study, it turned out that the measurement unit shell works as a resonator, so the shock loads on the micromechanical accelerometer can even exceed 1 000g. In this case, suspensions of the micromechanical accelerometer are deformed in the plane of the accelerometer, which causes their destruction. The solution to this problem was hampered by the strict limits on the overall dimensions of the device. The existing shock dampers that could absorb such shock loads simply did not fit into the attachment points. Therefore, an original spring was designed and manufactured for this purpose. At the final stage, an additional system of passive heat outlets from the accelerometer to the device shell was designed and installed.

Wave theory of the laminated plates with approximate consideration of the transverse shear

Composite materials are widely used in the production of aircraft for various purposes. Having several unique properties, composites, due to their heterogeneous structure, are poorly resistant to shock loads. Impulse action spreads inside the material in the form of stress waves, which are reflected on internal inhomogeneities, can overlap, and create very significant bursts of stress. This often leads to the well-known types of failure – spalling and delamination. Practice shows that these fractures occur almost immediately after the loading impulse. To verify the spalling strength, it is necessary to consider the initial unsteady phase of the response to the external impulse. There are sufficiently reliable theories to verify this strength; usually, they do not take transverse shear into account, otherwise the solution becomes unnecessarily cumbersome and poorly observable. Nevertheless, attempts are often made to refine the calculations by approximate consideration of transverse shear. This article presents the wave theory of laminated plates with approximate consideration of transverse shear. The possibility of specifying the calculation of impulse-loaded plates is considered. The inconsistency of the resulting model is proved.

Predicting the effect of bullets, shrapnel, explosions and other shock loads on military mobile robots

The factors that influence the probability of failure-free robots of mobile robots for military purposes are determined when they are hit by bullets, fragments, explosions and other shock loads. It has been established that the areas of greatest danger for special-purpose mobile robots are the barrel group, actuators, guidance system, ammunition stores, etc. On this basis, recommendations have been developed to improve the survivability of military mobile robots.

Shock Resistance Design of High-Speed Maglev Motor–Stability Considerations and Quantitative Shock Tests

Large external disturbances (such as shock loads) can cause contact between the rotor and touchdown bearings (TDBs). Hence, maintaining the stability of systems with active magnetic bearings (AMBs) is a major challenge for mobile applications such as on-board steam turbines or vehicle turbochargers. In this paper, two key factors (power bandwidth and bi-stable characteristic) that affect the shock stability of AMB-rotor systems are considered in the design of a high-speed maglev motor. Insufficient power bandwidth can induce current saturation leading to destabilization, while a bi-stable characteristic can cause persistent contact between the rotor and TDBs under external disturbances. Theoretical analyzes and criteria are provided, and the influence of these two factors is investigated by base shock experiments of a high-speed maglev motor. These experiments involved mounting a high-speed maglev motor on a shock table then subjecting it to shock loads of different amplitudes. The designed motor continued to operate stably under shock loads up to 20 G, verifying the correctness of the stability considerations.

OBTAINING NEW THIN WALLED TUBULAR STRUCTURES THROUGH MATRIX MORPHOLOGICAL RESEARCH

New products based on a structure that represents a combination of known elements in a higher quality set, as well as products that refer to new shapes, new curves, new surfaces can be obtained logically - analytically - deductively or by methods specific to the optimal calculation. The present paper focuses on the method of analyzing tridimensional morphology, some possible solutions being evaluated on value criteria. Of course, these methods can be applied in the field of engineering with very good results. The focus of this study is to obtain new thin walled tubular structures - such as car crash members - which in the case of axial shock loads have a higher predictable behavior compared to those already used in various technical fields. Following the study, it can be said that depending on the amount of absorbed energy in the case of axial collisions and the absorption of kinetic energy developed at the time of impact, the optimal crashworthiness solution could be tubular structures with a circular support base and rectangular deformable area for impact.