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Downloaded from https://www.everyspec.com -- MIL-STO-131ZB DEPARTMENT OF DEFENSE Washington, DC 20301. ,.. . I FASTENER TEST METHODS . ,:..:,: MIL-STD-1312B ,. ,., :..,, ,,, ..:.::, 1. This Military Standard is approved for use by all Departments’: and Agencies of the Department of Defense. .,:,., ,-::.:,,: I Beneficial comments (re~~~~nda~ions , ~ddition~, de~etion~) and ,, any,:pe”?tinentdata which may be of use in improving this document should’ >‘ be addressed to: Commanding Officer, Naval Air Engineering Center, Systems”Engineering and Standardization Department (SESD), Code 93, Lakehurst, NJ 08733, by using the self-addressed Standardization Docu-”‘“. ~.

ment Improvement Proposal (DD Form 1426) appearing at the end of this : document or by letter. % ,. ,, . ,. ;, : ,. ~ .. .. ) .!,, . .,:, ,/,,; ,. .t .:.,. .:, !.. ; ~ . ?;: ,. ... : ,,,. .. : . .. . .$..: .,. , ,-.,.,:..:... L .

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Downloaded from https://www.everyspec.com MIL-sTD-1312B FOREWORD 1. Background. The selection of fasteners in the design and construction fihase of weapons systems and equipments and the analysis of fasteners u8ed therein for parameters, such as suitability, standardization, and +jlification requires the evaluation and correlation of test data and:.~~; criteria. In evaluating these functions, it has become increasingly evident that the dats and criteria received from prime contractors, fastener producers, private laboratories, military docunents, and.rnilicaw laboratories cannot be adequately correlated.

The chief reason for this is the absence of unified standards prescribing test methods, procedures, fixtures, data analysis, and data presentation. ‘rbisdisparity encourages and often requires duplication of testing and reduces reliability.of ~ ~ , weapons systems and equipments, thereby impairing operations inv+ving erigineeringcontrol, design maintenance, quality assurance, standardizst$on, and,logistics simplification. TO correct this situation it was established that a unified set of test methods and procedures is required to serve as : i basic engineering tool for obtaining and presenting engineering data. As a result, this document was developed and prepared to satisfy this vital need.

This standard delineates standard test methods, procedures, conditions, fixtures, and methods of recording, analyzing and presenting test data. The purpose of the resulting test data is to determine the capability of fasteners to withstand the various environmental and meclianicalconditions encountered when used in military weapons systems. f Many benefits are to be expected by unified standard p Lts%%’Rieners. The following is a list of benefits that can be expected to accrue from using this standard. \ a. Availability of testing techniques and criteria necessary for the design and development of increasingly superior structural fasteners.

In the past, when a new fastener was needed to solve a problem, the necessary test procedures had to be developed and written; also, the macessary fixtures had to be designed. l’bisalways imposed delays, additional expenses, variations in test methods and in test results. b. Increasing incidence of correlation among fastener test data and design engineering techniques and design criteria for weapons systems and equipments.

As new systems are designed to achieve higher performance for a given volume and mass of material, it is essential that design data for structural joints (a large portion of which is obtained by testing fasteners) maintain a close correlation with engineering techniques and .: design criteria. Where weight is of importance, such as in aircraft structures, such close correlation will provide a substantial reduction in tie!ight . c. Availability of testing techniques and criteria necessary to mbintain consistent quality in the procurement of fasteners.

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Downloaded from https://www.everyspec.com MIL-s’rD-1312B d. Reduction in the time and effort required for the development of procurement specifications for fasteners by having a series of standard tests available. e. Elimination of duplication in the development of test methods and documents by individual fastener producers, Government contractor, and military activities. f. Elimination of duplication of effort in research and evaluation due to lack of unified standard teat methods.

When test methods are not standard, results cannot be correlated; therefore, producers, prime contractors, and military activities will not accept each other’a results and will duplicate research, development, and evaluation work. g. For logistics simplification, fastener attributes must be reduced to a common denominator so that variation .in type can be compared. Data and the presentation thereof, by means of this standard, will be provided in such form that various types and variation in types of fastenera may be compared to determine their degree of interchangeability, substitutability,and replaceability. ,h.

Time and effort required to reach agreement in regard to specific engineering changea will be reduced by providing unified standard tests for use in evaluating new fasteners. i. This standard will provide a means for establishing guidelines for evaluating fastener test data and engineering techniques. j. Industry and Government design personnel will become thoroughly indoctrinated in the uae of a single standard prescribing unified standard test methods.

ACKNOWLEDGEMENT This atandard was prepared by the Fastener Testing Development Group (FTDG), consisting of representatives of Government agenciea, engineering societies, trade associations, independent testing laboratories, the using industry, and the fastener producing industries. With the increased implementation of the International System of Units (S1) or metric system in military apecificationa and standards, the Department of Defense (DoD) haa approved its usage in this standard. Therefore, this issue, prepared under DoD project Number 53Gp-0142-20 by the FTDG, includes test methods in the S1 and inch-pound (I-P) units. . iv L

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Downloaded from https://www.everyspec.com MIL-sTD-1312B J TASLE OF CONTENTS Paragraph ~ 1: 1.1:. SCOPE .......................................... Applicability .................................. 1 1 2. 2.1 2.1.1 REFERENCED DOCUMENTS ........................... Government documents ........................... Specifications, standards and handbooka ........ 1 1 1 3. DEFINITIONS .................................... 1 4. 4.1 4.2 4.3 4.3.1 : GENERAL REQUIREMENTS ........................... Test method numbering system ................... Document format structure ...................... Method of revision ............................. Revision to test method number .................

1 1 2 2 3 3 3 4.4 4.5 Selection of teats ............................. Method of reference ............................ 5. DETAIL REQUIREMENTS ................’............ 4 APPENDICES Appendix A List of Available Teat Methods in Inch-Pound (I-P) Units .................................. List of Available Test Methods in International 5 B System (S1) Units ............................ Alignment and Load Verification of Axial-Load 6 c Fatigue Testing Machines ..................... 7

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