For engineers designing to MIL-STD-167-2A, the most critical section involves the specific test parameters.
, officially titled "Vibration, Mechanical (Shipboard Equipment)," is a United States military standard that establishes the vibration testing requirements for equipment installed aboard naval surface ships and submarines. It is the second revision of the original MIL-STD-167, specifically focusing on the environmental vibration durability of shipboard machinery, components, and systems.
A: No. MIL-STD-167-2A specifies sine wave sweep and dwell testing. Random vibration is covered elsewhere (e.g., NAVSEA specifications for submarine silencing).
Side-to-side vibrations affecting the propulsion shafting and associated machinery. Testing and Acceptance Criteria mil-std-167-2a pdf
Rotational twisting in reciprocating machinery and propulsion lines. MIL-STD-167-2A Fore-and-aft pulsing along propulsion system shafting. Type V (Lateral) MIL-STD-167-2A Side-to-side bending and whirling in propulsion shafting. Technical Deep Dive: The Core Vibration Types of 167-2A 1. Type III: Torsional Vibration
Conversely, equipment that successfully meets the standard’s requirements has demonstrated the ability to satisfactorily perform its intended functions while withstanding the demanding vibratory environment of shipboard operations.
Prevents axial resonance from overloading the ship's main structural thrust blocks and destroying hull-penetration seals. Type V: Lateral Vibrations For engineers designing to MIL-STD-167-2A, the most critical
Linear vibrations occurring along the axis of the propulsion system and shafting.
Naval vessels operate under harsh, high-stress maritime conditions. While external waves induce motion, some of the most destructive forces originate from within the ship. Heavy machinery, large propulsion shafts, and reciprocating engines create complex vibratory stresses. Left unchecked, these forces can degrade structural integrity, destroy bearings, strip gears, and compromise mission readiness.
The standard is split into two parts to address different vibration sources: Test Methods and Procedures
: It applies to machinery where standard vibration profiles might not be sufficient, such as antennas or large-scale machinery items. Key Vibration Classifications
This is a sine sweep test. The equipment is vibrated through a frequency range to simulate hull vibration.
If you are reviewing a supplier’s , ensure the report issuance date is within the last five years; older reports may reference superseded paragraphs.
Critical speed definitions (ensuring the operational RPM of a machine does not match the natural resonant frequency of the ship's hull). 4. Test Methods and Procedures