SOCIETY OFAUTOMOTIVE ENGINEERS, INC. TwoPennsylvania Plaza, NewYork, N.Y.10001 Reliability andMilitary Construction Equipment Arthur B.Follansbee and Lynwood M.Rabon U.S.Army Mobility Equipment Research andDevelopment Center National Combined Farm, Construction &Industrial Machinery andFuels andLubricants Meetings Milwaukee, Wis. September 10-13, 1973730847 Downloaded from SAE International by University of British Columbia, Tuesday, September 25, 2018Copyright ©Society ofAutomotive Engineers, Inc.1973 Allrights reserved. Downloaded from SAE International by University of British Columbia, Tuesday, September 25, 2018730847 Reliability andMilitary Construction Equipment Arthur B.Follansbee and Lynwood M.Rabon U.S.Army Mobility Equipment Research andDevelopment Center MILITARY CONSTRUCTION EQUIPMENT having ahigh degree ofreliability hasalways been ofinterest totheU.S. Army, and,recently, reliability hasbecome anexplicit specification requirement causing considerable reaction among industry andgovernment engineers. Theintent ofthispaper istoprovide engineers withanoverview ofthephilosophy by which reliability isbeing applied inArmy construction equip ment specifications. WHY BOTHER WITH RELIABILITY? Reliability isacharacteristic ofanitemofequipment which isoften expressed inabstract terms butisextremely difficult toquantify. AsLord Kelvin pointed out: "When youcanmeasure what youarespeaking about and express itinnumbers, youknow something about it;but when youcannot measure it,when youcannot express it innumbers, your knowledge isofameager andunsatis factory kind; itmaybethebeginning ofknowledge, but youhave scarcely inyour thoughts advanced tothestate ofscience, whatever thematter maybe."(1)* Interest inreliability started because there were excessive failures inmilitary electronic equipment during World WarII.Reliability asacharacteristic came intoitsownwith the advent ofmore complex aircraft, then missiles, submarines, andelectronic devices. After aquarter ofacentury, theneed andvalue ofhaving reliable equipment hasbeen firmly estab lished bythemilitary services. Improving reliability isnotan endinitself; rather, itHsasteptoward improving theefficiency ofexecuting theassigned military mission. Likewise, improv ingreliability reduces support andmaintenance costs, which have been estimated tobeupto25%oftheannual defense budget (2)orperhaps 10times orgreater theoriginal costof theequipment during its total life(3). Although improved reliability isadesirable equipment characteristic, itaddstotheacquisition costanddevelopment time. Therefore, itconflicts with theneed anddesire to obtain equipment atlowinitial costandinminimum time. Further, improved reliability places aburden onprocurement funds, whereas highfailure rates arepaidforastheequipment isused andplace aburden onoperating funds. Themilitary procurement funds andoperating funds aretotally separate budgets andcannot easily betraded off. WHAT ISRELIABILITY? Reliability isdefined byArmy Regulation (4)as:"The probability thatanitem willperform toitsintended function foraspecified interval under stated conditions."*Numbers inparentheses designate References atendof paper. ABSTRACT Because reliability isanintegral partofmilitary planning and hastremendous impact onoperations andlogistics, explicit reliability requirements haverecently become partofmany specifications usedbytheU.S.Army forprocuring construc tionequipment. Reliability isdiscussed inthecontext of construction equipment, particularly thedifficulty inobtainingdata, defining failures, andtherisks involved indemonstra tiontests. Thesuccessful application ofreliability require ments inmilitary specifications depends onacoordinated effort between industry andgovernment working within commonly understood meanings ofreliability anditsramifi cations. Downloaded from SAE International by University of British Columbia, Tuesday, September 25, 20182 Thisdefinition hasfourimportant parts: 1.Aquantitative probability value.2.Ade