IS 8252 Pt.14-1982

标准号：IS 8252 Pt.14-1982
发布日期：1982/11/1 12:00:00
实施日期：1999/12/31 12:00:00
适用范围：This standard specifies mechanical vibration tests used to verify the minimum requirements needed to demonstrate that, under the influence of vibratory stresses likely to be encountered in an aircraft, aircraft equipment has a satisfactory performance within the specified limits of use and is free from obvious defects in design and construction.1.1 In the case of equipment which is expected to have a high level of reliability and/or high structural integrity, the client and/or the approving authority may require additional endurance testing. Such tests shall be defined by the client.1.2 As the duration of the test is short relative to the service life of the equipment, reliability and fatigue aspects are not taken into account in this standard. It relates only to rectilinear vibrations applied successively along the three reference axes of the equipment.1.3 By classifying equipment in three categories representing the major types of aircraft— helicopters, turbine-engined aircraft, and piston — engined aircraft— it is possible to select frequency ranges and levels which are sufficiently varied.1.4 Two classes of severity levels are proposed : standard levels and severe levels.1.5 In general, the test proper (endurance phase ) is performed in accordance with one of the following methods, as required by the client.— Sinusoidal vibrations with logarithmic frequency sweep;— Sinusoidal resonance frequency vibrations;— Wide band random vibrations; or— Narrow band random vibrations with logarithmic frequency sweep.1.6 In the specific cases of equipment intended for one type of aircraft, and where vibration recordings are available, recorded vibration tests may be carried out.1.7 In special cases where one or more specific frequencies exist within the vibratory spectrum of a particular aircraft, sinusoidal vibration tests at these fixed frequencies may be specified by the client.