共查询到19条相似文献,搜索用时 125 毫秒
1.
2.
3.
4.
本文通过一系列的公式推导,叙述小型跌落冲击台的工作原理,并对两类实际冲击波形进行了分析,提出了几点改进措施,以达到增加τ值提高小型冲击台的性能的目的。 相似文献
5.
本文阐述了凸轮式跌落冲击台的结构原理,力学性质,冲击参数及其调整方法,凸轮式跌落冲击台产生的次冲击能够影响试件的测试参数并能引起试件的疲劳损伤,本文还说明了消除次冲击的方法。 相似文献
6.
7.
本文指出,文献[1]中给出的冲击波形内的插点数不能适应现代测试技术的需要,提出插点数应由被测试波形的种类,测试的参数及测试参数的精度要求来决定。本文给出相应的计算公式。 相似文献
8.
9.
10.
冲击作用与冲击模拟环境在电磁振动台上的实现 总被引:1,自引:0,他引:1
简要论述了几种典型激励作用下的冲击作用,以及利用小波合成法控制冲击谱在电磁振动台上进行冲击模拟环境的试验方法,对于进行冲击环境的模拟有一定的借鉴之处。 相似文献
11.
12.
13.
14.
结合试验指标要求,对温度冲击试验设备实现途径进行分析比较,选择两箱式作为试验设备的实现方式;对设备组成结构及制冷、加热流程进行阐述,并对温度冲击试验过程中两种制冷状态下的热负荷进行了分析计算。 相似文献
15.
主要应用于舰船等有冲击场合的断路器,其抗冲击性能要求很高。介绍了断路器欠压脱扣器在抗冲击方面的设计方法,此方法可以有效地削弱冲击力对欠压脱扣器的影响。 相似文献
16.
17.
网络的发展从仅关注速度的提升转移到关注业务的交付能力,由此网络可靠性问题越来越受到研究者的重视。网络可靠性试验是评价网络可靠性的一种重要手段,而试验流量的生成对可靠性评价结果具有决定性的影响。然而目前从可靠性角度对网络进行试验时,对任务的描述较为简单,无法支撑由客户需求分解到网络流量生成的全过程;从流量模型角度出发的生成技术则仅关注全网流量,难以支持可靠性试验中的流量生成。本文提出基于业务的混合模型的流量描述方法,并使用软件实现,最后进行试验验证所提出方法的有效性。 相似文献
18.
Hanson N 《Journal of environmental management》2011,92(3):610-619
Field surveys of biological responses can provide valuable information about environmental status and anthropogenic stress. However, it is quite usual for biological variables to differ between sites or change between two periods of time also in the absence of an impact. This means that there is an obvious risk that natural variation will be interpreted as environmental impact, or that relevant effects will be missed due to insufficient statistical power. Furthermore, statistical methods tend to focus on the risks for Type-I error, i.e. false positives. For environmental management, the risk for false negatives is (at least) equally important. The aim of the present study was to investigate how the probabilities for false positives and negatives are affected by experimental set up (number of reference sites and samples per site), decision criteria (statistical method and α-level) and effect size. A model was constructed to simulate data from multiple reference sites, a negative control and a positive control. The negative control was taken from the same distribution as the reference sites and the positive control was just outside the normal range. Using the model, the probabilities to get false positives and false negatives were calculated when a conventional statistical test, based on a null hypothesis of no difference, was used along with alternative tests that were based on the normal range of natural variation. Here, it is tested if an investigated site is significantly inside (equivalence test) and significantly outside (interval test) the normal range. Furthermore, it was tested how the risks for false positives and false negatives are affected by changes in α-level and effect size. The results of the present study show that the strategy that best balances the risks between false positives and false negatives is to use the equivalence test. Besides tests with tabulated p-values, estimates generated using a bootstrap routine were included in the present study. The simulations showed that the probability for management errors was smaller for the bootstrap compared to the traditional test and the interval test. 相似文献