Browse Topic: Vibration
The effective measurement and verification of dimensional stability indicators for large size and highly stable structures in service environments is the key to the development of high-precision spacecraft technology. Spatial carrier speckle interferometry technology has been widely used for high-precision measurements in recent years due to its advantages of fast speed, high accuracy, and simple operation. However, the existing technical research only focuses on the measurement under normal temperature and pressure environments, and there is little research on the application under complex operating conditions in space. There is currently no relevant research on the impact of system ambient vibration and noise on measurement stability disturbances. In response to the above issues, a high-precision deformation measurement system suitable for complex environments of high and low temperatures in a vacuum was designed based on spatial carrier measurement technology. A system measurement
According to a problem of the vibration and noise suppression of an engineering vehicle cab, a dynamical model of the engine-frame-cab system was established to describe the vibration transmission path. The method of calculation of the vibratory power flow, which is transmitted from the vibration source engine to the cab through the frame and isolators, was deduced. And then an optimization strategy for the frame structure and the corresponding analysis algorithm process were proposed based on the objective function of power flow. The method proposed was validated through an application to a practical example, which would have practical value in the field of vehicle vibration reductions and optimization design of frame structures.
With the continuous development of avionics systems towards greater integration and modularization, traditional aircraft buses such as ARINC 429 and MIL-STD-1553B are increasingly facing challenges in meeting the demanding requirements of next-generation avionics systems. These traditional buses struggle to provide sufficient bandwidth efficiency, real-time performance, and scalability for modern avionics applications. In response to these limitations, AFDX (Avionics Full-Duplex Switched Ethernet), a deterministic network architecture based on the ARINC 664 standard, has emerged as a critical solution for enabling high-speed data communication in avionics systems. The AFDX architecture offers several advantages, including a dual-redundant network topology, a Virtual Link (VL) isolation mechanism, and well-defined bandwidth allocation strategies, all of which contribute to its robustness and reliability. However, with the increasing complexity of onboard networks and multi-tasking
Anticipated NOX emission standards will require that selective catalytic reduction (SCR) systems sustain exhaust temperatures of 200°C or higher for effective conversion performance. Maintaining these temperatures becomes challenging during low-load conditions such as idling, deceleration, and coasting, which lower exhaust heat and must be addressed in both regulatory test cycles and day-to-day operation. Cylinder deactivation (CDA) has proven effective in elevating exhaust temperatures while also reducing fuel consumption. This study investigates a flexible 6-cylinder CDA system capable of operating across any combination of fixed firing modes and dynamic skip-firing patterns, where cylinders transition between activation states nearly cycle-by-cycle. This operational flexibility extends the CDA usable range beyond prior implementations. Data was primarily collected from a test cell engine equipped with the dynamic CDA system, while a matching engine in a 2018 long-haul sleeper cab
The smart industrial revolution in any organization brings faster product delivery to the market, which can meet customer expectations and full life requirements without failure. Failure per machine (FPM) is a very critical metric for any organization considering warranty cost and customer perception. One such area which needs a detailed evaluation is bolted joints. Bolts play a pivotal role when integrating a subassembly with the main structure. Often, it is challenging to address bolt failure issues due to vibration induced in structures. Current bolt virtual evaluation methods help to evaluate bolts in simple loading conditions such as axial and bending loads. But it is quite complicated to evaluate the bolts which are prone to vibration loading. Traditional methods of using gravity loads miss out on dynamic characteristics, hence it must be simulated using modal dynamic analysis. With the current vADV (virtual accelerated design verification) method it is not possible to capture
This paper studies an important industrial controls engineering problem statement on mitigating vibrations in a mechanical boom structure for an off-highway agricultural vehicle. The work discusses the implementation of an active force control concept to efficiently dampen out vibrations in a boom. Through rigorous simulation comparison with respect to an existing PID mechanism, the efficacy of the AFC is demonstrated. A notable reduction of 60 % to 70 % in the boom vibrations was observed.
Noise generated by a vehicle’s HVAC (Heating, Ventilation, and Air Conditioning) system can significantly affect passenger comfort and the overall driving experience. One of the main causes of this noise is resonance, which happens when the operating speed of rotating parts, such as fans or compressors, matches the natural frequency of the ducts or housing. This leads to unwanted noise inside the cabin. A Campbell diagram provides a systematic approach to identifying and analyzing resonance issues. By plotting natural frequencies of system components against their operating speeds, Test engineers can determine the specific points where resonance occurs. Once these points are known, design changes can be made to avoid them—for example, adjusting the blower speed, modifying duct stiffness, or adding damping materials such as foam. In our study, resonance was observed in the HVAC duct at a specific blower speed on the Campbell diagram. To address this, we opted to optimize the duct design
The height valve adjusting rod is an important part of the suspension system, used to adjust the height of the train to adapt to the train through the curve, slope or uneven track when the height valve adjusting rod fracture failure, the train’s suspension system can not be adjusted normally, may lead to the height of the train is too high or too low, affecting the stability of the train and the driving safety. In this paper, an underground vehicle height valve adjusting rod fracture failure of the problem was studied and analysed, the specific conclusions are as follows: height valve adjusting rod there are two main vibration frequency, 60Hz and 340Hz, 60Hz main frequency has always existed, and 340Hz vibration frequency are present in part of the interval, but also caused by the vehicle vibration of the main reason for the local larger; height valve adjusting rod stress there is also a significant vibration The main frequency of 340Hz, similar to the vibration characteristics of the
Items per page:
50
1 – 50 of 3547