528.1-22 applicable documents and definitions

528.1-2 ACQUISITION REQUIREMENTS

Acquisition documents should specify the following:

• a. Title, number, and date of the method.
• b. Reporting requirements, including requirements for Notification of Test, Equipment Test Plan, and/or Test Report (see paragraphs 4.1, 5.1.2.5.1, and 5.1.2.5.2 in the front part of this Method).
• c. Identification of component compliance on component drawing, in Test Report, or on label plate (see paragraph 4.2).
• d. Disposition of tested equipment and related equipment (see paragraph 4.3 in the front part of this Method).
• e. Type(s) of vibration required (see paragraphs 5.1 and 5.2 in the front part of this Method).
• f. Type I:
• (1) How the equipment will be operated after the test to demonstrate the machinery or equipment has no damage from the test, including acceptable operational degradations (see paragraphs 5.1.1 and 5.1.2.4.1 in the front part of this Method).
• (2) Whether the test engineer needs concurrence of the procuring agency for determination of major vs. minor failures before continuing testing (see paragraph 5.1.1 in the front part of this Method).
• (3) Whether measurement transducer locations need to be approved by the procuring agency for Type I testing (see paragraph 5.1.2.2) in the front part of this Method).
• (4) Methods of mounting equipment for test (see paragraph 5.1.2.3.4 in the front part of this Method).
• (5) Whether internal mounts should be installed for all, a specific part, or none of the test (see paragraph 5.1.2.3.5 in the front part of this Method).
• (6) How the test item will be energized or operated during Type I vibration tests (e.g., pressure, flow rate, voltage current, and cycling of principal functions during testing), including acceptable operational degradations (see paragraphs 5.1.1 and 5.1.2.4.1 in the front part of this Method).
• (7) When required, the maximum test frequencies (see paragraph 5.1.2.4.4 in the front part of this Method)

MIL-STD-810H METHOD

528.1-2 DISTRIBUTION OF CLIMATIC DESIGN TYPES

There are four climatic design types: Hot (A1 and B3), Basic (A2, B1, B2, and C1), Cold (C2), and Severe Cold (C3). Figure 1 shows land areas where the four climatic design types apply. Discussion of the delimitation of the climatic conditions (paragraph 2.2) is included to permit proper interpretation and use of the map. The primary basis for delimiting the climatic conditions is temperature; secondary consideration is given to humidity conditions.

528.1-2 MIL-HDBK-310

MIL-HDBK-310, “Global Climatic Data for Developing Military Products,” includes extensive information regarding extreme natural environments. Consult MIL-HDBK-310 directly for more specific details.

The following data table was extracted from a publication by Dr. Paul Krause and Ms. Kathleen Flood of the Army Topographic Engineering Center. The publication is: Krause, P.F. and K.L. Flood. 1997. Weather and Climate Extremes (Technical Report TEC-0099). Alexandria, VA: U.S. Army Topographic Engineering Center.

Table A-I. Weather & Climatic Extremes – Brief Summary.

MIL-STD-810H

PART THREE ANNEX A

Table A-I. Weather & Climatic Extremes – Brief Summary – continued

MIL-STD-810H PART THREE ANNEX A

Figure description:

TEMPERATURE EXTREMES

TEMPERATURE EXTREMES

Source: Compiled by Engineer Research and Development Center, U.S. Army Topographic Engineering Center, Alexandria, Virginia, for "Weather and Climate Extremes", 1997 [Extremes updated through January, 2003 Notes: The map displays various temperature extremes recorded globally, including record highs and lows, largest changes, and highest/lowest averages.

MIL-STD-810H

PART THREE ANNEX A

Table A-II Precipitation extremes

MIL-STD-810H

PART THREE ANNEX A

Table A-II Precipitation extremes – continued

MIL-STD-810H

PART THREE ANNEX A

Figure description:

PRECIPITATION EXTREMES

World Precipitation Extremes Map

Annotations

• Thompson Pass, Alaska: Not an official record (text_label - position: Alaska)
• Barot, Guadeloupe: Exact coordinates unknown (text_label - position: Guadeloupe)
• Muduoxiang, China: Exact coordinates unknown (text_label - position: China)

Source: Engineer Research and Development Center, U.S. Army Topographic Engineering Center, Alexandria, Virginia. Compiled for 'Weather and Climate Extremes', 1997 [Extremes updated through January, 2003 Notes: The map displays extreme precipitation events and average precipitation records worldwide. It includes various categories such as rainfall, snowfall, hail, and dry periods. Values are provided in standard and metric units where applicable.

MIL-STD-810H

PART THREE ANNEX A

Table A-III. Miscellaneous extremes

MIL-STD-810H PART THREE ANNEX A

Figure description:

MISCELLANEOUS EXTREMES

MISCELLANEOUS EXTREMES

Annotations

• Red dots indicate specific locations of the recorded weather extremes. (point_marker - position: Various locations across the world map)

Source: Engineer Research and Development Center, U.S. Army Topographic Engineering Center, Alexandria, Virginia Notes: The map provides various record-breaking meteorological data points including wind speed, barometric pressure, humidity, and thunderstorm frequency across different continents. Compilation date: 1997, with extremes updated through January 2003.

MIL-STD-810H PART THREE ANNEX B

PART THREE ANNEX B - Terminology

528.1-2.1 Determining and Displaying Transmissibility

Present transmissibility information using the output responses and prescribed inputs. Use the transmissibility magnitudes for both exploratory and variable frequency tests for response prominence determinations.

528.1-2.1 Hot climatic design type (A1 and B3)

The areas where hot conditions apply include most of the low latitude deserts of the world. During summer in these areas, temperatures above 43°C (110°F) occur frequently, but except for a few specific localities, temperatures will seldom be above 49°C (120°F). In winter, temperatures are not likely to be extremely low so that the low temperatures of the basic climatic design type apply. If materiel is designed only for the hot type, a special recommendation for low temperature design values should be sought. Limited portions of this area are sometimes subject to very high absolute humidity, although the highest temperatures and highest dewpoints do not occur at the same time.

The world's highest air temperatures occur in the areas identified with the hot climatic design type in Figure 1. This area is hotter than the basic design type with a 1-percent temperature of 49°C (120°F) in the hottest parts. These are primarily low latitude deserts that, in addition to very high air temperatures, concurrently experience very low relative humidity (except in the hot humid areas) and intense solar radiation. Two daily cycles, described in paragraphs 4.1.1.1 and 4.1.3.1 make up the hot design type. They are:

• a. Al Hot-dry (paragraph. (Paragraph 4.1.1.1)

b. B3 Hot-humid. (Paragraph 4.1.3.1)

2.1.1 Transmissibility Magnitudes

Develop transmissibility magnitudes by dividing the measured output amplitudes by the input amplitudes using consistent units (e.g., acceleration in gs or inches/sec²).

2.1.2 Transmissibility and Frequency

Present transmissibility information in linear-linear format. Plots or tabulations are acceptable. Present both the transmissibility and frequency information in linear units (i.e., do not use logarithms or dB of either frequency or transmissibility to compute or display the data used for response prominence determinations).

MIL-STD-810H

METHOD 528.1

that the vibration of the journals or forces on the bearings, at a frequency corresponding to operational speed, are within specified limits.

• e. Balancing, multi-plane. Multi-plane balancing refers to any balancing procedure that requires unbalance correction in more than two axially separated correction planes.
• f. Balancing, single-plane (static). Single-plane (static) balancing is a procedure by which the mass distribution of a rigid rotor is adjusted in order to ensure the residual static unbalance is within specified limits, and that requires correction in only one plane. (Note: Single-plane balancing can be done on a pair of knife edges without rotation of the rotor, but is now more usually done on centrifugal balancing machines.)
• g. Balancing, two-plane (dynamic). Two-plane (dynamic) balancing is a procedure by which the mass distribution of a rigid rotor is adjusted in order to ensure that the residual unbalance in two specified planes is within specified limits.
• h. Critical speed. Critical speed is the speed of a rotating system that corresponds to a natural frequency of the system.
• i. Environmental vibration. Environmental vibration is vibratory force that is imposed on equipment installed aboard ships under all external conditions. The hydrodynamic force from the propeller blades interacting with the hull is usually the principal exciting force.
• j. Equipment. Equipment is any rotating or non-rotating machine that is intended to be installed aboard ship.
• k. Grade, balance quality. Balance quality grade, G, refers to the amount of permissible unbalance of a rotor. The balance quality grade is the product of the maximum permissible eccentricity (distance between the shaft axis and the rotor center of gravity (in mm)) and the rotational velocity (radians/sec). The units for balance quality grade, G, are mm/sec. By this definition, a particular grade rotor will be allowed a mass eccentricity (e=G/ω), that is inversely proportional to the operating speed.

1. Internally excited vibration. Internally excited vibration is vibration of machinery generated by mass unbalance of a rotor.

• m. Isolation mount. An isolation mount is a device used to attenuate the force transmitted from the equipment to its foundation in a frequency range.
• n. Mass unbalance. Mass unbalance occurs when the mass centerline does not coincide with the geometric centerline of a rotor.
• o. Maximum design rpm. Maximum design rpm is the highest shaft rpm for which the ship is designed.
• p. Method of correction. A method of correction is a procedure, whereby the mass distribution of a rotor is adjusted to reduce unbalance or vibration due to unbalance, to an acceptable value. Corrections are usually made by adding materiel to, or removing it from, the rotor.
• q. Mode. Natural Mode is the manner or pattern of vibration at a natural frequency, and is described by its natural frequency and relative amplitude curve.
• r. Plane, correction. A correction plane is a plane transverse to the shaft axis of a rotor in which correction for unbalance is made.
• s. Plane, measuring. A measuring plane is a plane transverse to the shaft axis in which the amount and angle of unbalance is determined.
• t. Residual unbalance. Residual unbalance is unbalance of any kind that remains after balancing.
• u. Resonance. Resonance is the structural response that occurs when a linear lightly damped system is driven with a sinusoidal input at its natural frequency in which the response prominence is greater than one.
• v. Response prominence. Response prominence is a general term denoting a resonance or other distinct maximum, regardless of magnitude, in a transmissibility function, including local maxima that may exist at the frequency endpoints of the transmissibility function. Typically, a response prominence is identified by the frequency of its maximum response that is the response prominence frequency. A response prominence of a system in forced oscillation exists when any change, for both plus and minus increments however small,

in the frequency of excitation results in a decrease of the system response at the observing sensor registering the maximum. A response prominence may occur in an internal part of the equipment, with little or no outward manifestation at the vibration measurement point, and in some cases, the response may be detected by observing some other type of output function of the equipment, such as voltage, current, or any other measurable physical parameter. Instruction on how to identify response prominences is provided in Annex A.

• w. Rotor, flexible. A flexible rotor is one that does not meet the criteria for a rigid rotor and operates above its first resonance. The unbalance of a flexible rotor changes with speed. Any value of unbalance assigned to a flexible rotor must be at a particular speed. The balancing of flexible rotors requires correction in more than two planes. A rotor that operates above $n$ resonances requires $n+2$ balance planes of correction. A rotor that operates between the second and third resonances, for example, requires $2+2$ balance planes of correction.
• x. Rotor, rigid. A rotor is considered to be rigid when its unbalance can be corrected in any two arbitrarily selected planes and it operates below its first resonance. After correction, its residual unbalance does not exceed the allowed tolerance, relative to the shaft axis, at any speed up to the maximum service speed and when running under conditions that approximate closely to those of the final supporting system.
• y. Simple harmonic motion. A simple harmonic motion is a motion such that the displacement is a sinusoidal function of time.
• z. Test fixture resonance. A test fixture resonance is any enhancement of the response of the test fixture to a periodic driving force when the driving frequency is equal to a natural frequency of the test fixture.
• aa. Transmissibility. Transmissibility is the non-dimensional ratio of the response amplitude in steady-state forced vibration to the excitation amplitude. The ratio may be one of forces, displacements, velocities, or accelerations. Transmissibility is displayed in a linear-linear plot of transmissibility as a function of frequency, or in tabular form. Instructions for determining and displaying transmissibility are given in paragraph 2.1 of Annex A.
• bb. Vibration resistance. It is measured by mechanical impedance – how hard it is to make mechanical systems vibrate. It is a ratio of the exciting force to the velocity response. Low impedance implies low force and/or high velocity—a system that is easy to excite.

528.1-2.2 Identifying Response Prominences

Regardless of whether or not the transmissibility exceeds 1.0, find all local maxima in the transmissibility magnitude-frequency data and include the frequency endpoints in the list of maxima.

• a. For each of these maxima, determine if there is reason to believe that the maximum is attributable to an instrumentation error, a fixture resonance or from a numerical error related to computation of the transmissibility (round-off errors may appear as maxima). Any maxima that are attributable to an instrumentation error, fixture resonance, or numerical errors must be discarded as a potential response prominence. Fixture resonances are not permitted, and refixturing must be employed to eliminate such resonances.
• b. Examine the end points for indications that a resonance may exist outside the test frequency range.
• c. An initial decrease in transmissibility with increasing frequency above the frequency of the lower end point suggests a potential response prominence outside the lower bound of the test frequency range. If this condition is observed and is not attributed to shaker problems at low frequencies, include the lower endpoint in the candidate list of endurance test frequencies noting whether or not it affects functional or structural integrity. If this condition is not observed, the lower bound test frequency may be discarded as a potential response prominence. At these low frequencies, noticeable displacement magnitude amplifications may occur if a true response prominence exists below the lower frequency bound of testing and this fact may be used to help determine the nearby presence of a true response prominence.
• d. Similarly, an increase in transmissibility with increasing frequency near the upper bound test frequency suggests a potential response prominence outside the upper bound of the test frequency range. If this condition is observed, include the upper endpoint in the candidate list of endurance test frequencies noting whether or not it affects functional or structural integrity. If it is not observed, this frequency cannot be excluded from the list of endurance test frequencies unless other response prominence frequencies are found.
• e. Observe whether or not equipment function (if permitted by the ordering data) or structural integrity is affected at any of the frequencies used in exploratory or variable frequency testing. Include those frequencies at which equipment functional or structural integrity is affected in the candidate list of endurance test frequencies. Also include frequencies at which maxima occur in the candidate list of endurance test frequencies if the impact on functional/structural performance cannot be established.

MIL-STD-810H

METHOD 528.1 ANNEX A

• f. Examine the remaining maxima for classic signs of resonance (i.e., a moderate to rapid increase in transmissibility to the peak followed by a moderate to rapid decrease in the transmissibility with increasing frequency after the peak suggests that a response prominence may exist in this region) and include any maxima that exhibit these characteristics in the candidate list of endurance test frequencies.

528.1-2.2 Basic climatic design type

The area this type applies to includes the most densely populated and heavily industrialized parts of the world as well as the humid tropics. The entire range of basic design conditions does not necessarily apply to any one place. Each single design condition (high temperature, low temperature, and high humidity) applies to a widespread area. When taken together, the design values should provide for satisfactory materiel throughout the area involved. Tropical areas are included in the basic climatic design type because the temperature of the humid tropics is quite moderate, and the humidity is also experienced in the midlatitudes. The unique feature of the tropics that makes it important to materiel is the persistence of high humidity over long periods of time. This condition not only promotes corrosion but is an excellent environment for insect and microbiological damage.

The Basic is by far the largest of the four climatic design types. However, this large area has one constant characteristic: it has no extremely hot or cold conditions. Nevertheless, non-temperature dependent design problems within the Basic Design Type can vary with the magnitude and persistence of humidity conditions. The basic area has 1-percent cold and hot temperatures of -31.7°C (-25°F) and 43.3°C (110°F) during the worst month in the coldest and hottest parts of the regional type, respectively. The Humid Tropics are largely confined to areas between the Tropics of Capricorn and Cancer, whereas other areas of the Basic Design Type (Basic Hot & Basic Cold) range from the Tropics to the polar regions. These other areas include most of the densely populated, industrialized, and agriculturally productive land of the world.

The humid tropics and the midlatitudes (basic design type) are characterized by temperatures more moderate than the extremes of the other design types. Areas where the basic type applies are more widespread than the hot and cold design types combined. They also include most of the densely populated, highly industrialized sectors of the world. Because microbial deterioration is a function of temperature and humidity and is an inseparable condition of hot humid tropics and the mid-latitudes, consider microbial deterioration in the design of all standard general-purpose materiel. Four daily cycles, described as shown below are recognized for the basic design types. They are:

• a. (B1) Constant high humidity (paragraph 4.2.3).
• b. (B2) Variable high humidity (paragraph 4.2.4).
• c. (A2) Basic hot (paragraph 4.2.5)
• d. (C1) Basic cold (paragraph 4.2.6)

MIL-STD-810H

PART THREE

528.1-2.3 Cold and severe cold design types

The areas designated as cold, and severe cold, primarily northern North America, Greenland, northern Asia, and the Tibetan Highlands of China, were delimited because of the occurrence of low temperatures. In the area of the cold design type, temperature during the coldest month in a normal year may be colder than the basic cold extreme of -32°C (-25°F). In the severe cold areas, temperature during the coldest month in a normal year may be colder than the cold extreme of -46°C (-50°F), but colder than -51°C (-60°F) no more than 20 percent of the hours in the coldest month in the coldest part of the area (such as northern Siberia where absolute minimum temperatures as low as -68°C (-90°F) have been recorded). Because the extreme low temperatures are not controlled by a daily solar cycle, they persist for a long enough period of time for materiel to reach equilibrium at a temperature near the minimum.

The cold climatic design type areas in Figure 1 that are confined to the Northern Hemisphere have temperatures much lower than the basic cold areas, but not as low as the severe cold areas. It has a 1 percent temperature of

-45.6°C (-50°F) in the coldest parts. The cold cycle is described in paragraphs 4.2.6 - 4.3.2.

The severe cold climatic design type areas in Figure 1 have the lowest temperatures on the surface of the earth, except for Antarctica (that is not considered in this document). It has a 20-percent temperature of -51°C (-60°F) in the coldest parts. These low temperatures are found in the northern continental interiors and the Arctic. The severe cold condition is described in paragraph 4.3.3.

2.3.1 Non-responsive Prominence Frequencies Where Functional or Structural Integrity Is Affected

Include in the list of endurance test frequencies, any frequency at which a structural, functional, mechanical, or electrical anomaly has occurred (if permitted by the acceptance criteria (see paragraph 5.1.1 at the beginning of this Method, as well as Annex B, paragraph 2f(1)). Examples of these manifestations could be unexpected switch closures, unexpected changes in pressure or flow, variations in voltage, current, etc. The frequencies where any minor impairment of function occurs that does not warrant interruption of testing to develop a fix must also be included in the list of endurance test frequencies.

2.3.2 Frequencies Where Response Prominences Have Been Identified

Components may contain many parts and subassemblies that can resonate. Some components may have nonlinear characteristics such as clearances between parts or equipment mounted on isolation mounts. Therefore, the amplitude of excitation may be important relative to identifying response prominences for these components. Input amplitude dependent response prominences may potentially be the same overall resonance rather than different ones. In light of this potential, unusual test results, such as uncovering response prominences during variable frequency testing that were not uncovered during exploratory testing, need to be thoroughly investigated to not only try and determine the cause of the response prominence but to ascertain whether the response prominence is unique or part of another response prominence. Criteria for selecting response prominences for endurance testing are as follows:

• a. A transmissibility greater than 1.5 at any measurement location is sufficient to classify a maximum as a response prominence, and include the corresponding frequency in the list of endurance test frequencies. However, the converse is not necessarily true, i.e., a response prominence whose transmissibility is less than 1.5 cannot be excluded solely on the magnitude of the transmissibility. Possible explanations as to why transmissibility maxima of magnitudes less than 1.5 may still represent real response prominences are:
• (1) The transducer may not be at the point of maximum response. If probing or some other means cannot be employed to locate the point of maximum response (e.g., due to inaccessibility), then all maxima displaying the classic characteristics of a resonance that cannot be attributed to instrumentation or numerical error must be identified as response prominences, and their frequencies included in the list of endurance test frequencies.
• (2) The transducer may be at or near a response node point (location of minimal or low response in a vibration mode) at that frequency. The location of node points (as well as the locations of maximum response) can change location as changes in the drive frequency excite different modes of vibration.
• (3) The mass of the part and the amplitude of vibration of the mass that is in maximum response are not large enough to generate the forces necessary to cause structural responses of large enough magnitude at the location of the transducer.
• (4) The driving frequency is not exactly at the resonant frequency, thus the peak response is not obtained.
• b. Without further investigation, the existence of a response prominence for the remaining maxima cannot be confirmed, nor the possibility of the existence of a response prominence excluded. If practical, an attempt should be made to obtain further information to resolve this issue by probing for the maximum response location with movable transducers, listening, visually locating or feeling for the maximum response points.
• c. If it can be shown that response prominences uncovered do not compromise equipment structural/functional integrity, these response prominences do not have to be included in the endurance test. Justification should be provided in the test report as to why these response prominences have been excluded from endurance testing.

MIL-STD-810H METHOD

MIL-STD-810H

METHOD 528.1 ANNEX A

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MIL-STD-810H

METHOD 528.1 ANNEX B

METHOD 528.1, ANNEX B NOTES AND ENGINEERING GUIDANCE

(This Annex contains information of a general or explanatory nature that may be helpful, but is not mandatory.)

528.1-2.4 Absolute maximum and minimum temperatures

2. Absolute maximum and minimum temperatures. Figures 2 and 3 are included to show the absolute maximum and minimum temperatures that have been observed. The maps are generalized because of data limitations, and the uneven occurrence of extremes.

MIL-STD-810H PART THREE

Figure description:

Key Information:

• Subject: Global map of Climatic Design Types.
• Climatic Categories:
  • Hot (Red: Northern/Central Africa, Middle East, South Asia, Central Australia, and Southwest US/Mexico border.
  • Basic (Yellow: Predominant category covering most of South America, Europe, sub-Saharan Africa, and Central/Southeast Asia.
  • Cold (Blue: Northern North America (Canada/Alaska and Northern Eurasia (Russia.
  • Severe Cold (Black: High Arctic regions including Northern Canada, Greenland, and parts of Northern Siberia.
• Source: Prepared by The U.S. Army Topographic Engineering Center, Alexandria, Virginia.
• Projection: Aitoff's Equal Area Projection adapted by V. C. Finch.
• Document Context: MIL-STD-810H, Part Three.

MIL-STD-810H

PART THREE

Figure description:

Key Information:

• Subject: Global distribution of absolute minimum temperatures.
• Source: U.S. Army Topographic Engineering Center; part of MIL-STD-810H Part Three.
• Key Entities: Displays extreme cold zones across the Northern Hemisphere, specifically concentrated in Northern Canada, Greenland, and Siberia (Russia.
• Projection: Aitoff's Equal Area Projection.

PART THREE-6

MIL-STD-810H PART THREE

Figure description:

World Absolute Maximum Temperatures

ABSOLUTE MAXIMUM TEMPERATURES ABOVE 40.6°C (105°F

Legend

• Above 51.7°C (125°F — color: Black; symbol: Solid rectangle
• 46.1°C to 51.7°C (115° to 125°F — color: Dark Red; symbol: Solid rectangle
• 40.6°C to 46.1°C (105° to 115°F — color: Orange; symbol: Rectangle with diagonal hatching
• Below 40.6°C (Below 105°F — color: Yellow; symbol: Solid rectangle

Annotations

• Approximate Scale along Equator: 0-3000 Kilometers / 0-2000 Miles (scale_bar - position: Bottom right, above projection note)
• AITOFF'S EQUAL AREA PROJECTION Adapted by V. C. Finch (text_label - position: Bottom right corner)
• The representation of international boundaries on this map is not necessarily authoritative. (text_label - position: Vertical text on the bottom right edge)

Source: Prepared by The U.S. Army Topographic Engineering Center, Alexandria, Virginia Notes: The map uses Aitoff's Equal Area Projection. Data covers global landmasses with focused detail on heat-extreme regions.

PART THREE-7

MIL-STD-810H

PART THREE

SECTION III – NATURAL AND INDUCED ENVIRONMENT - VARIOUS ELEMENTS