1 Scope
This document specifies the requirements and procedures for impulse testing of hose, pipe and fitting assemblies for use in aerospace hydraulic systems.
This document applies to the impulse test of hose, pipe and fitting components for aerospace hydraulic systems. This document may also be used for component testing of other applicable aerospace fluid systems.
2 Normative references
The contents of the following documents constitute essential provisions of this document by means of normative references in the text. Where the references are dated. Only the version corresponding to that date applies to this document; for undated references, the latest version (including all amendment sheets) applies to this document.
ISO 6771 Aerospace- Fluid systems and com- ponents- Pressure and temperature classifications
ponents- Pressure and temperature classifications)
ISO 8575 Aerospace- Fluid systems- - Hydraulic system tubing
tubing)
3 Terminology and definitions
The following terms and definitions apply to this document.
3.1 Rate of rise
Rate of rise
Defines the slope of the rise in pulse pressure (straight line section) in the pressure/time characteristic curve.
Note: The rate of rise can also be defined as the rate of change in pressure between 10% and 90% of the total rise in pulse pressure from back pressure to peak pressure.
3.2
Peak pressurepeak pressure
The maximum value of the working pressure in a short period of time.
[Source: GB/T 30206.1- 2013,2.25]
4 Test conditions.
4.1 Pulse traces
When observed on an oscilloscope, the pulse traces represent approximate pressure/time cycles. These pressure/time profiles should be within the shaded area shown in Figure 1. The dynamic pulse traces produced by the pulse test equipment should be - consistent with the pulse traces shown in Figure 1.
4.2 Calculation of lift rate
The lift rate shall be calculated according to equation (1):
n a rate of rise in kilopascals per second (kPa/s);
-peak pressure in kPa (kPa);
t2 - the time required to reach the moment 0.9p in seconds (s);
t, the time required to reach the moment of 0.1p in seconds (s).
4.3 Preparation of specimens
The preparation of the specimen should be in accordance with the relevant handling and testing requirements in the product specification.
4.4 Test fluid
The test fluid shall be the specified aerospace hydraulic system fluid or other hydraulic fluid compatible with the specimen.
5 Purpose of the test
The purpose of this test method is to determine the ability of hose, pipe and fitting assemblies to withstand hydraulic shock for qualification testing under simulated conditions.
6 Test method
To test hoses. Tube and fitting assemblies. including base or port fittings. Unless otherwise specified, peak pressures and lift rates shall be set in accordance with Table 1, peak pressures and lift rates (imperial units of measurement) are given in Table 2 and the test sequence shall be performed in accordance with Table 3.
Adjust the oscilloscope. Make sure that the peak pressure rise trace fills the oscilloscope display screen and that the pulse cycle trace is accurately recorded by photographic or other more accurate recording means, with grid lines or other markings on the photograph so that the pressure and time values at each point on the trace can be accurately checked and read. The end-to-end accuracy and sampling rate of the data acquisition system and sensor should ensure that the pulse measurement uncertainty is within the pressure waveform range of this document. The accuracy of the measurements shall be in accordance with the relevant standards.
The total number of cycles shall be 200,000 unless otherwise specified in the procurement specification.
As shown in Table 3, after the temperature has stabilised at the maximum or minimum value, a minimum holding time of 1 h is required before the start of the test sequence section. if the procurement specification requires temperature control. The fluid temperature should be measured at the test manifold. The ambient temperature test position should be approximately 150 mm from the specimen.
The peak pressure should be measured at the test manifold at the furthest end of the specimen.
7 Intended use
7.1 Standardisation
The purpose of this document is to facilitate the standardisation of impulse test requirements for hydraulic hose, pipe and fitting assemblies, standard identification and procedures and equipment for evaluating impulse tests.
7.2 Citation
If this document is cited in the specification as a requirement - part. The following additional requirements shall be specified:
a) Nominal pressure;
b) Limit working temperature;
c) specimen design.
Foreword
Introduction
1 Scope
2 Normative references
3Terms and definitions
4Test conditions
5Test purpose
6Test methods
7 Intended use
Bibliographical
1范围
本文件规定了用于航空航天液压系统的软管、管道和接头组件的脉冲试验的要求和程序。
本文件适用于航空航天液压系统的软管、管道和接头组件的脉冲试验。本文件也可用于其他适用的航空航天流体系统的部件试验。
2规范性引用文件
下列文件中的内容通过文中的规范性引用而构成本文件必不可少的条款。其中,注日期的引用文.件，仅该日期对应的版本适用于本文件;不注日期的引用文件,其最新版本(包括所有的修改单)适用于本文件。
ISO6771航空航天 流体系统和部件 压 力和温度分类( Aerospace- Fluid systems and com-
ponents- Pressure and temperature classifications)
ISO 8575航空航天流体系统液 压系统管路( Aerospace- Fluid systems- - Hydraulic system
tubing)
3术语和定义
下列术语和定义适用于本文件。
3.1
升率rate of rise
定义压力/时间特性曲线中,脉冲压力上升部分(直线段)的斜率。
注:升率也可定义为脉冲压力从背压升高到峰值压力的总上升量的10%~90%之间的压力变化率。
3.2
峰值压力peak pressure
短时间内工作压力的最大值。
[来源:GB/T 30206.1- 2013,2.25]
4试验条件.
4.1脉冲迹线
在示波器上观察时,脉冲迹线代表了近似的压力/时间循环。这些压力/时间曲线应在图1所示的阴影区域范围内。脉冲试验设备产生的动态脉冲迹线应与图1所示的脉冲迹线--致。
4.2升率的计算
升率应按公式(1)计算:
n一升率,单位为千帕每秒(kPa/s);
-峰值压力,单位为千帕(kPa);
t2-一达到0.9p的时刻所需的时间,单位为秒(s);
t，一达到0.1p的时刻所需的时间,单位为秒(s)。
4.3试样的制 备
试样的制备应符合产品规范中相关的处理和测试要求。
4.4试验 流体
试验流体应是指定的航空航天液压系统流体或与试样相容的其他液压油。
5试验目的
本试验方法旨在确定软管、管道和接头组件承受液压冲击的能力，以便在模拟条件下进行鉴定试验。
6试验方法
为测试软管.管道和接头组件.包括底座或端口接头.循环速率应为(70士5)次/min。除非另有规定,峰值压力和升率应按表1设定,表2给出了峰值压力和升率(英制计量单位),试验顺序应按表3执行。
调整示波器.使峰值压力上升迹线能占满示波器显示屏幕,采用照相或其他精度更高的记录手段准确记录脉冲循环迹线,照片上应有格栅线或其他标志,以便能准确地检查和读出迹线上各点的压力值和时间值。数据采集系统和传感器的端到端精度和采样率应确保脉冲测量不确定度在本文件的压力波形范围内。测量的准确性应符合相关标准。
除非采购规范另有规定,循环总数应为20万次。
如表3所示，当温度稳定在最大值或最小值后，在试验序列部分开始之前至少需要保温1 h。如果采购规范要求温度控制.则应在试验歧管处测量流体温度。环境温度试验位置应距离试样约150mm。
应:在试样最远端试验歧管处测量峰值压力。
7预期用途
7.1标准化
本文件旨在促进液压软管、管道和接头组件的脉冲试验要求、标准鉴定和评估脉冲试验的程序和设备的标准化。
7.2引用
如:果在规范中引用本文件作为要求的--部分.则应指定以下附加要求:
a) 名义压力;
b) 极限工作温度;
c) 试样设计。
