Hongyan Zhu, Pengzhen Lv, Xiaochong Wu, Yuansheng Wang, Wei Liu, Huagang Lin and Zhufeng Yue
This paper aims to propose a two-stage vibration isolation system for large airborne equipment to isolate aircraft vibration load.
Abstract
Purpose
This paper aims to propose a two-stage vibration isolation system for large airborne equipment to isolate aircraft vibration load.
Design/methodology/approach
First, the vibration isolation law of the discrete model of large airborne equipment under different damping ratios, stiffness ratios and mass ratios is analyzed, which guides the establishment of a three-dimensional solid model of large airborne equipment. Subsequently, the vibration isolation transfer efficiency is analyzed based on the three-dimensional model of the airborne equipment, and the angular and linear vibration responses of the two-stage vibration isolation system under different frequencies are studied.
Findings
Finally, studies have shown that the steady-state angular vibration at the non-resonant frequency changes little. In contrast, the maximum angular vibration at the resonance peak reaches 0.0033 rad, at least 20 times the response at the non-resonant frequency. The linear vibration at the resonant frequency is at least 2.14 times the response at the non-resonant frequency. Obviously, the amplification factor of linear vibration is less than that of angular vibration, and angular vibration has the most significant effect on the internal vibration of airborne equipment.
Originality/value
The two-stage vibration isolation equipment designed in this paper has a positive guiding significance for the vibration isolation design of large airborne equipment.
Details
Keywords
Hongyan Zhu, Xiaochong Wu, Pengzhen Lv, Yuansheng Wang, Huagang Lin, Wei Liu and Zhufeng Yue
Improvement and optimization design of a two-stage vibration isolation system proposed in this paper are conducted to ensure the device of electronic work effective.
Abstract
Purpose
Improvement and optimization design of a two-stage vibration isolation system proposed in this paper are conducted to ensure the device of electronic work effective.
Design/methodology/approach
The proposed two-stage vibration isolation system of airborne equipment is optimized and parameterized based on multi-objective genetic algorithm.
Findings
The results show that compared with initial two-stage vibration isolation system, the angular vibration of the two-stage vibration isolation system becomes 3.55 × 10-4 rad, which decreases by 89%. The linear isolation effect is improved by at least 67.7%.
Originality/value
The optimized two-stage vibration isolation system effectively improves the vibration reduction effect, the resonance peak is obviously improved and the reliability of the mounting bracket and the shock absorber is highly improved, which provides an analysis method for two-stage airborne equipment isolation design under complex dynamic environment.
Details
Keywords
John A Parnell, Zhang Long and Don Lester
The purpose of this paper is to investigate linkages among competitive strategy, strategic capabilities, environmental uncertainty, and organizational performance in small and…
Abstract
Purpose
The purpose of this paper is to investigate linkages among competitive strategy, strategic capabilities, environmental uncertainty, and organizational performance in small and medium sized enterprises (SMEs) in China and the USA.
Design/methodology/approach
In China, a survey was administered to managers of SMEs in Shanghai and Guangzhou. In the USA, a survey was administered to managers of SMEs in three major cities. Competitive strategy, capabilities, uncertainty, and performance were measured by previously validated scales.
Findings
Findings support the integrity Miles and Snow generic strategic typology. Performance satisfaction was significantly lower in firms employing a reactor strategy as opposed to those employing prospector, defender, or analyzer strategies. Additional support was found for the concept of strategic clarity, as businesses reporting moderate strategic clarity had lower levels of satisfaction with performance than those reporting either a single strategy or a combination emphasis on three equal strategies.
Practical implications
Chinese SMEs tend to prefer cost-based approaches to their local markets. A differentiation market approach is challenging in most local Chinese economies due to the low wages of most jobs in an economy that is still largely centrally planned. In the USA, more disposable income leads to more market opportunities. While this situation is gradually changing in China, it is not at a point where SMEs feel comfortable pursuing totally differentiated strategies.
Originality/value
Several distinctions in competitive strategy, capabilities, and environmental uncertainty between China and the USA are recognized by analysis. Analyzers and defenders in Chinese SMEs tend to follow industry prospectors with lower prices and/or superior service. They might change strategies after gaining a foothold in the market. Performance for SMEs with low strategic clarity often depends on established guanxi with governmental agencies or stated-owned enterprises, a situation very different from that in the USA.