A6 (CUI) NSWC PCD VendorAnalysisInformation.pptx

19 October 2022

NAVSEA WARFARE CENTERS | CUI

NAVSEA WARFARE CENTERS | CUI

Shock Isolator Analysis Vendor Information DISTRIBUTION STATEMENT D. Distribution authorized to the Department of Defense and U.S. DoD contractors only (critical technology, export-controlled). Other requests shall be referred to the Office of Naval Research, Code 35.

WARNING - This document contains technical data whose export is restricted by the Arms Export Control Act (Title 22, U.S.C., Sec 2751, et seq.) or the Export Administration Act of 1979 (Title 50, U.S.C., App. 2401 et seq.), as amended. Violations of these export laws are subject to severe criminal penalties. Disseminate in accordance with provisions of DoD Directive 5230.25.

Controlled by: ONR Code 35 CUI Category: CTI Distribution Statement: D POC: patrick.delay@navy.mil

Ensuring Warfighting Dominance in the Littoral Battlespace

NAVAL SURFACE WARFARE CENTER PANAMA CITY DIVISION

Expanding the Advantage through Collaboration

Analysis Objectives and Outputs Analysis Purpose Perform a 6 degree-of-freedom analysis of the system during the specified transit drop shocks to identify the best arrangement of shock isolator mounts for this application and specify the isolator mounts to be used.

Analysis Objectives Specify the part numbers of the shock isolator mounts to be used for this application Identify the placement and arrangement of the shock isolator mounts to be used for this application Model the system response to the transit drop shocks in the locations defined below Analysis Measurements All outputs to be measured at the following locations:

Payload front bulkhead, payload center of mass, payload rear bulkhead Peak displacement response of payload in each transit drop shock event Peak acceleration response of payload in each transit drop shock event Peak displacement response of all shock isolator mounts in each transit drop shock event System rigid-body natural frequencies Measurements of the forces within the shock isolators. (Ideally as response over time from the shock events; can be the peak forces for each drop orientation)

Shock Absorption Background Design constraints Design for a five foot drop height and a 30 G fragility level Threshold dropped on bottom, front, and rear faces also at 45 degree angle on front and rear bottom edges Objective dropped on left and right side faces, and on 45 degree angles on left and right bottom edges.

Support the payload in key areas to minimize bending loads.

Tentative Dimensions Case dimensions can be adjusted as required, with the ultimate objective being to minimize internal volume yielding a lower weight.

Protective case internal dimensions:

82.75” L x 22” W x 16.8” H Protective case external dimensions (maximum allowable):

84.0” L x 26.0” W x 22.5” H Payload dimensions (x2):

77" L x 6.2" W x 7" H, Flanges: 7.6" W x 8.3" H (see CAD model)

Analysis Description Transit Drop Shock Orientations Nine transit drop shock orientations are to be considered. The first five orientations are threshold requirements and the shock isolation systems will have to be designed to pass each of these requirements.

All tests are to be performed IAW MIL-STD-810H, Method 516.8, Procedure IV On bottom face, from five feet height On front face, from five feet height On back face, from five feet height On front, bottom edge, from five feet (include secondary impact if possible) On back, bottom edge, from five feet (include secondary impact if possible) The last four orientations are objectives. NSWC PCD is requesting that the system response is identified for these four orientations but potential solutions do not need to meet the 30g fragility requirement in these directions.

On left face, from five feet height On right face, from five feet height On left, bottom edge, from five feet (include secondary impact is possible) On right, bottom edge, from five feet (include secondary impact is possible)

Analysis Description Impact Surface

Direction of Motion Impact Surface

Direction of Motion Bottom Face Impact Front & Rear Face Impact

System Top Face

Analysis Description Impact Surface

Direction of Motion Front and Back Edge 45° Impact Impact Surface

Analysis Description Impact Surface

Direction of Motion Left and Right Side Impact (Derived requirement) Impact Surface

Analysis Description Impact Surface

Direction of Motion Left and Right Edge 45° Impact (Derived requirement) Impact Surface

System Description NSWC PCD is tasked with integrating a payload into a transportation protective case. The payload consists of two masses bound together by three interface brackets Mass properties:

Sprung mass: 175 lbs (see next slide) Center of mass: 33.5 inches aft of front bulkhead

CG

-33.5” from front bulkhead, centered laterally & vertically

System Description This table lists the mass properties of the sprung components (per item) Mass moment of inertia are provided relative to the item’s center of mass Output coordinate system:

X-axis: Aligned with longitudinal direction Y-axis: Aligned with vertical direction Z-axis: Aligned with lateral direction

This payload weight will likely change. Perhaps to 200 lbs total

Datum Support points/planes are measured relative to the front bulkhead (shown as the datum below).

Datum

0.7" Keep Out Zones Dimensions for keep out zones are provided below (pink colored regions):

2.75" 4" 1.5" 0.9" 2.5"

System Description

Isometric View Front Face Back Face Right Face X Z Y Left Face

System Description Side View (Payload) Y X 82.75" (Case Interior) 16.8" (Case Interior) 77.0" 8.28" (Payload)

System Description Top View Z X 22" (Internal) 7.55" Intentional stagger/offset to minimize lateral width

Payload Support Points

SP 4

SP 2

SP 3

SP 1

SP 5

SP 6

SP 7

+Y +X

Payload CG -33.5” from datum, centered laterally & vertically The highlighted support points have been identified as the areas that are most likely to need support to minimize bending stresses within the payload

Placement of Shock Isolators The placement of the shock isolators is predetermined in the Y-Z plane based on our interface brackets. This could be adjusted based on your feedback.

The placement of the shock isolators along the length of the payload is subject to the following tolerances. Feel free to adjust the placement of the shock isolators within the given tolerances. The dimensions are measured from the front bulkhead.

Middle Shock Isolators Front Shock Isolators Aft Shock Isolators Front Bulkhead *Measurements given are from Front Bulkhead to midplane of Shock Isolators. Subject to change.

**Provided Aft range is given as if rear keep out zone is not present. Location of rear keep out is subject to change.

System Description Views for better perspective on flange & payload axial profile.

Profile of payload between flanges can be seen here.

Shock isolators cannot be situated in the axial direction between the flange and case (front and rear ends)

7” 6.2”

Cage/Frame/Skeleton Concept Material Options: Aluminum, Titanium, or Carbon Fiber Depicted in 45 degree corner mounting orientation. Shear mounted or alternative alternation of mounting positions can be explored if viable.

Anchored through the bottom edges of the case (typically the thickest part with rotomolded cases, can be recessed and capped).

Bracket/Carriage Views 45 degree mounting concept to maximize isolator capability & minimize case volume.

Due to weight, desire is to limit number of support structures to 3, max 4.

8.6" 14.6" 22" 15.2"

4"

Questions?

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