04/15/2003 1

TACOMLethality, Survivability, Mobility and

Sustainment for America’s Army

ELIMINATING PROPELLANTELIMINATING PROPELLANT BAG DETERIORATON BAG DETERIORATON

38TH ANNUAL GUN, AMMUNITION, AND MISSILESSYMPOSIUM & EXHIBITION

24-27 MARCH 2003

Presented by

Adriana EngU.S. Army Armament Research, Development and Engineering Center

Picatinny Arsenal, New Jersey 07806-5000

Leadership Teaming Communication Employee Support Strategic Thinking Organizational Climate

04/15/2003 2

ØEliminate rapid deterioration ofpropellant bagØImprove safety and reliabilityØExtend service lifeØReduce life cycle cost

04/15/2003 3

ITEM DESCRIPTIONITEM DESCRIPTION

105mm M1 Cartridge withM67 Propelling Charge

04/15/2003 4

ØOver three million 105mm rounds inunserviceable conditions due to propellantbag deterioration

ØRayon propellant bag deterioration

• Observed in as little as 3 to 4 years

• Bags no longer hold propellant safely

• Require expensive rework ($114/round)

04/15/2003 5

ØEarly studies determined• Cloth deterioration caused by propellant outgas

and moistureüNitrogen dioxide + H2O => Nitric Acid

• Acrylic cloth is significantly more resistant tonitric acid than rayon cloth

04/15/2003 6

TECHNICAL APPROACHTECHNICAL APPROACH

ØAssure chemical compatibility between acrylic andM1 propellantØMaintain proper test controls

• Manufacture two sets of M67 charges:ü“Test charges” with acrylic propellant bagsü“Control charges” with rayon propellant bags

ØEstablish Evaluation Criteria, comparison of clothsbased on:• Ballistic performance• Residue evaluation• Simulated rough handling and transportation• Shelf Life

04/15/2003 7

RESULTSRESULTSCOMPATIBILITY TESTCOMPATIBILITY TEST

Requirement:(MIXTURE GAS) – (ACRYLIC GAS + M1 PROPELLANT GAS) < 3 ml

Result:6.38 ml – (5.55 ml + 0.35 ml) = 0.48 ml

PASS

04/15/2003 8

RESULTS (CON’T)RESULTS (CON’T)BALLISTIC PERFORMANCE AT +70BALLISTIC PERFORMANCE AT +70==FF

Zone 3 Pressure Range at 70 deg F

9000

9500

10000

10500

ZONE 3(SPEC)

ZONE 3(ACRYLIC)

ZONE 3(RAYON)

PS

I

Zone 3 Velocity Standard Deviation at +70 deg F

0.0

1.0

2.0

3.0

4.0

5.0

6.0

SPEC ACRYLIC RAYON

ZONE 3

Zone 7 Velocity Standard Deviation at +70 deg F

0.0

1.0

2.0

3.0

4.0

5.0

6.0

SPEC ACRYLIC RAYON

ZONE 7

Zone 7 Pressure Range at 70 deg F

30000

32000

34000

36000

38000

40000

ZONE 7(SPEC)

ZONE 7(ACRYLIC)

ZONE 7(RAYON)

PS

I

04/15/2003 9

RESULTS (CON’T)RESULTS (CON’T)BALLISTIC PERFORMANCE AT -50BALLISTIC PERFORMANCE AT -50==F &F &

+145+145==FF Zone 7 Average Pressure + 4 Sigma at -50 deg F(Propellant Uniformity Series)

32000

35000

38000

41000

44000

SPEC(PIMP)

ACRYLIC RAYON

PS

I

Zone 7

Zone 7 Average Pressure + 4 Sigma at +145 deg F(Propellant Uniformity Series)

32000

37000

42000

47000

SPEC(PIMP)

ACRYLIC RAYON

PS

I

Zone 7

Zone 7 Average Pressure + 4 Sigma at -50 deg F(Sequential Environmental)

32000

35000

38000

41000

44000

SPEC (PIMP) ACRYLIC RAYON

PS

I

Zone 7

Zone 7 Average Pressure + 4 Sigma at +145 deg F(Sequential Environmental)

32000

35000

38000

41000

44000

SPEC (PIMP) ACRYLIC RAYON

PS

I

Zone 7

04/15/2003 10

RESULTS (CON’T)RESULTS (CON’T)CLOTH RESIDUE EVALUATIONCLOTH RESIDUE EVALUATION

Ø RAYON RESIDUE:ØACRYLIC - NO RECOVERABLE RESIDUE

04/15/2003 11

NUMBER OF BAG DAMAGES AFTER LOOSE CARGO VIBRATION

0

5

10

15

20

25

30

35

40

acrylic bags rayon bags

+ 145 deg F- 50 deg F

% DAMAGED M67 CHARGES AFTERLOGISTIC VIBRATIONS

RESULTS (CON’T)RESULTS (CON’T)SEQUENTIAL ENVIRONMENTAL TESTSSEQUENTIAL ENVIRONMENTAL TESTS

0

10

20

30

40

acrylic bags rayon bags

Per

cen

tag

e (%

)

+ 145 deg F- 50 deg F

04/15/2003 12

RESULTS (CON’T)RESULTS (CON’T)PROPELLANT BAG SHELF LIFE STUDYPROPELLANT BAG SHELF LIFE STUDY

Rayon bag12 weeks

Rayon bag16 weeks

0 week

ØEXPERIMENTAL METHOD•DURATION: UP TO 48 WEEKS•CONDITIONING: 65=C, 75=C, 85=C, 95=C AT 75% RH•SAMPLING: WEEKLY (RAYON) & MONTHLY (ACRYLIC)

04/15/2003 13

0

10

20

30

40

50

60

70

80

90

%

Rayon (fill) Rayon (w arp) Acrylic (fill) Acrylic (w arp)

Cloth Type

85 deg C

RESULTS (CON’T)RESULTS (CON’T)% REMAINING TENSILE STRENGTH AFTER 12 WEEKS% REMAINING TENSILE STRENGTH AFTER 12 WEEKS

0

10

20

30

40

50

60

70

80

90

100

%

Rayon (fill) Rayon (w arp) Acrylic (fill) Acrylic (w arp)

CLOTH TYPE

75 deg C

0

10

20

30

40

50

60

70

80

90

100

%

Rayon (fill) Rayon (w arp) Acrylic (fill) Acrylic (w arp)

Cloth Type

65 deg C

Left bars = Rayon clothRight bars = Acrylic cloth

04/15/2003 14

RESULTS (CON’T)RESULTS (CON’T)PREDICTED TENSILE STRENGTH LOSSPREDICTED TENSILE STRENGTH LOSS

acrylic rayon

0 10 20 30 40 50

0.0

0.1

0.2

0.3

year

fract

ion

loss

Figure 1. Predicted Fraction Loss in Tensile Strength at 25 deg C & 75% RH

acrylic rayon

0 10 20 30 40 50

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

year

fract

ion

loss

Figure 2. Predicted Fraction Loss in Tensile Strength at 35.38 deg C & 75% RH

11 TIMES3.4 years37 years35.38ºC & 75% RH

9 TIMES16 years143 years25=C & 75% RH

ACRYLIC BETTERTHAN RAYON BY

RAYONCLOTH

ACRYLICCLOTH

ARRHENIUS DEGRADATION MODEL2:Log (S) = a + t ß exp ( - ? / T)

PREDICTED SHELF LIFE BASED ON 10% LOSS IN TENSILE STRENGTH1

Note: Based on data collected over 32 weeks.

04/15/2003 15

SUMMARYSUMMARY

ØAcrylic propellant bags have beensuccessfully qualified as a replacement forrayon bags based on• High resistance to bag deterioration• Met shelf life requirements• Comparable ballistic performances• Less cloth residue• More durable for rough-handling and

transportation

ØEliminate rework of propellant bags