1、FORD LABORATORY TEST METHOD BO 012-04 2001 0822 2001 0327 DYNAMIC FLEX FATIGUE TEST FOR FOAM AND FIBER PADS Revised Typographical corrections to section 14 A. Cockman Revised Editorial - no technical change A. Cockman Application Method A of this procedure is used to determine the load bearing prope
2、rties, loss of thickness and the amount of structural breakdown of polyurethane foam seating materials, such as topper pads and molded assem blies. Method B is used to evaluate the resistance of carpet insulating fiber pads to fiber separation, breakdown and destruction from dynamic flexing. Scope M
3、ethod A simulates conditions which contribute to breakdown of polyurethane foam, resulting in loss of load bearing properties and loss of thickness. A test specimen is measured for thickness under a specified load, mounted on the fixture shown in the illustration and subjected to dynamic fatigue by
4、compression and directional deformation. This is accomplished by rolling the specimen diagonally under constant load for a specified number of cycles. Specimen thickness under a constant load is obtained after a one hour recovery period following dynamic fatigue to determine loss in foam thickness a
5、nd load bearing characteristics. Method B simulates heel action on the carpet which could be a contributor to the breakdown of brittle fibers in the carpet underlayment. The test specimen is examined for fiber separation, breakdown and destruction after dynamic flexing. This flexing is accomplished
6、by subjecting a carpet and fiber pad composite to a specified number of reciprocating rubbing cycles with a metal heel simulator under a specified constant load. Conditioning and Test Conditions All test values indicated herein are based on material conditioned in a controlled atmosphere of 23 +/- 2
7、 OC and 50 +/- 5 % relative humidity for not less than 24 h prior to testing and tested under the same conditions unless otherwise specified. I I Date I Action I Revisions Copynght02001, Ford Global Technologies, Inc FORD LABORATORY TEST METHOD BO 012-04 Method A Apparatus Required Load Deflection T
8、est Apparatus BurkePorter or equivalent (see Figure 1). An apparatus having a flat circular indenter foot, 323 cm2 in area and dead weight loaded through a swivel joint (capable of accommodating the angle of the sample) with loads of 4.4 N, 11 1 N, 222 N, and 75 Ibs. 334 N shall be mounted over a le
9、vel horizontal 375 x 375 mm platform with 6.35 mm holes on 19 mm centers. The distance between indenter foot and platform shall be variable to compress sample under test at a speed of 50 mm/minute for thickness measurements or 200 mm/minute for preflex conditioning and shall be measured with a gage
10、measuring device. This apparatus shall be used in the constant load or indentation residual gage load (IRGL) test. Source: BurkePorter Machinery Co. Grand Rapids, Michigan (Specify Model 445) Dynamic Fatigue Apparatus The equipment for dynamic fatigue of the specimen is shown in the attached photogr
11、aph (see Figure 2). The apparatus consists of the following parts: 1. A perforated base plated with 6.35 mm diameter holes on 19 mm centers. 2. A roller 460 mm long and 75 mm in diameter mounted in an offset position (15“) with suitable means for a specified load on the test specimen. The test is co
12、nducted at the rate of 24 - 28 cycles/ minute (one cycle consists of one forward and one reverse stroke). 3. Motor and gear box for actuating the roller. 4. Counter for recording test cycles. 5. Sturdy table for mounting and supporting of the entire apparatus. Source: Rise Machine Company 905 N. Kin
13、ney Mt. Pleasant, Michigan 48858 Specify Job No. 42. Equivalent apparatus may be used. Page 2 of 10 Copynght02001, Ford Global Technologies, Inc FORD LABORATORY TEST METHOD BO 012-04 Cotton Sheeting ESB-MSH13-A, or equivalent. Generally used as a headlining listing. 76 mm wide strips are required -
14、two pieces shall be 360 mm long and two shall be 430 mm long. This material is bonded to the base of the foam pad with latex base adhesive and is used to secure the test specimen to the platen with metal retainer straps. Ad hesive ESB-M2G17-A, solvent release type, or ESB-M2G110-A, water emulsion la
15、tex base adhesive, or equivalent. Either of these materials may be used to bond the cotton sheeting strips to the base of the foam pad. Procedure 1. 2. 3. 4. 5. Cut a test specimen 305 x 380 x 50 mm thick from a representative sample of current production polyurethane foam (slab or molded). The leng
16、th and width shall be measured with a tape or scale so that the dimensions are within +/- 6 mm. The samples shall be sawed with a scalloped blade. Sufficient time should be allowed for complete recovery. Four 75 mm wide pieces of cotton sheeting shall be required - two 360 mm long and two 430 mm lon
17、g. Bond the cotton sheeting strips to the bottom surface of the specimen with a solvent or water emulsion type of adhesive. Allow 50 mm of each strip to extend beyond the edges of the test specimen so that the specimen can be securely held in place on the base platen of the fatigue machine by the us
18、e of metal retainer straps. Condition the test specimen, undeflected and undistorted, at a temperature of 22 +/- 3 OC and in an atmosphere of 50 +/- 5 % relative humidity for at least 12 h before being tested. This 12 h minimum waiting period serves as a conditioner for the foam as well as a drying
19、time for the adhesive used to bond the sheeting 83 the foam. All subsequent tests should also be conducted under the above temperature and relative humidity conditions. All tests shall be performed a minimum of 7 days after the foam has been manufactured. Place the test specimen on the supporting pl
20、ate of the load deflection test apparatus. If the sample has one side cored or honeycombed, this face shall rest on the perforated plate. For specimens of uniform thickness, the position shall be such that the indentation will be made at the center of the specimen. For assemblies of varying thicknes
21、s, the area shall be selected which provides an approximate average thickness. In either case, the indentation area shall be suitably identified with a marking pencil so that subsequent indentation will be performed in exactly the same area. Deflect the test specimen ten times, using the 334 N load
22、at the 200 mm/ minute speed. The specimen shall then be allowed to rest in an undeflected and undistorted position for a period of 5 minutes. Page 3 of 10 Copynght02001, Ford Global Technologies, Inc FORD LABORATORY TEST METHOD BO 012-04 6. Bring the ndenter foot into contact with the test specimen,
23、 applying a preload of 4.4 N at 50 mm/minute and determine the height or thickness of the test specimen by means of the indicator. In the case of contoured pads, in order to achieve maximum free height accuracy, place a wooden template 38 x 50 x 380 mm in length under the center of the indentation a
24、rea. Template may be provided with locator pins to prevent movement during measurement. Indenter Foot Pad Tem p I ate 7. Within 1 minute of Step 6, apply and maintain a constant 222 N load at the rate of 50 mm/minute in the area previously deflected. Read and record the specimen thickness exactly 1
25、minute after a load of 222 N is reached. 8. Adjust the load on the dynamic fatigue machine roller to obtain a 133 N load (or load specified in the applicable ES-M specification), when the pivot arms are in the horizontal position. (See Figure 3 for method of weighing roller assembly.) Mount the test
26、 specimen on the base platen of the dynamic fatigue machine and secure by means of the cotton sheeting and metal retainer straps. 9. Operate machine so roller traverses foam specimen two or three times. Then stop machine and rotate drive pulley so roller is approximately in center of foam specimen.
27、Then adjust the height of the base platen so that the pivot arms holding the roller will be horizontal (use a level positioned on the pivot arm) when the roller is resting on the foam. (This step is important and assures that the load will always be constant at the start of the test.) IO. Set the co
28、unter to zero, start the machine and flex the sample for the required number of cycles. A standard test consists of 20,000 cycles (40,000 flexes). 11. After dynamic fatigue, condition the sample at 22 +/- 3 OC and 50 +/- 5 % relative humidity for 1 h (+ 1 O, - O minutes) in an undistorted and undefl
29、ected position. 12. Repeat Steps 4 through 7 of the test procedure. 13. Check the specimen for physical breakdown of the cellular structure by visual examination and comparison with unflexed specimens. Page 4 of 10 Copynght02001, Ford Global Technologies, Inc FORD LABORATORY TEST METHOD BO 012-04 14
30、. Calculate and report the percent of loaded height loss under 222 N load as follows: Ft= to- tf x 100 to Where: Ft = percent loss of thickness to = original specimen thickness under 222 N load tf = final specimen thickness under 222 N load The percent of loaded height loss reported should be the av
31、erage of a minimum of two fatigued samples. 15. Calculate and report the percent 4.4 N preload height loss after fatigue as follows: (Oriainal Gaae CCU 4.4 N) - (Final Gaae CCU 4.4 N) x 100 = % Loss Original Gage 4.4 N The percent of loaded height loss reported should be the average of a minimum of
32、two fatigued samples. Method B Dynamic Fatigue Apparatus The test apparatus shall be identical to that required for Method A except that the 460 mm long by 75 mm diameter roller is replaced by a 100 mm long x 50 mm diameter solid metal rod with a hemispherical rubbing surface 25 mm radius at one end
33、 and a threaded bit at the other end for mounting centrally to the roller carriage in a tapped hole located in the center of the load pan. The perforated platform is also replaced by, or covered by, a smooth surface. (Refer to Figure 4 showing the apparatus.) “C“ Clamps (4 required) Use 75 mm “C“ Cl
34、amps, one at each corner, to hold the carpet-padding composite test specimen to the test platen. Standard Carpet Standard carpet sections 255 x 510 mm of ESB-M3H20-B, cut pile nylon, shall be used for all Method B tests. Master Samples Following dynamic flex fatigue testing to this Method B, the tes
35、t specimen shall be compared to a similarly tested master approved sample. Test samples must equal to or exceed performance of master samples. Master samples are available from the appropriate Product Engineering Office. Page 5 of 10 Copynght02001, Ford Global Technologies, Inc FORD LABORATORY TEST
36、METHOD BO 012-04 Procedure 1. Place a composite test specimen, consisting of a 255 x 510 mm section of standard carpet (pile side up) over a 255 x 510 mm section of fiber pad on Dynamic Flex Tester platen. Secure in place with “C“ clamps, one clamp on each corner of composite. Orient the 510 mm dime
37、nsion parallel to the direction of reciprocating stroke. 2. Remove the fatigue roller and install the metal rod (heel simulator) as shown in Figure 4. 3. Add sufficient weight so that the carriage, metal rod and added load shall weigh 289 +/- 9 N when measured with the carriage horizontal as shown i
38、n Figure 4. 4. Subject the test composite to the number of reciprocating cycles specified in the applicable Engineering Materials Specification. (1 cycle consists of 1 forward and 1 reverse stroke.) 5. At the conclusion of the test, examine the fiber pad test sample for fiber separation, breakdown o
39、r destruction, compared to master fiber pad sample. Report results as required by the Engineering Materials Specification. Chemicals, materials, parts, and equipment referenced in this document must be used and handled properly. Each party is responsible for determining proper use and handling in it
40、s facilities. Page 6 of 10 Copynght02001, Ford Global Technologies, Inc FORD LABORATORY TEST METHOD BO 012-04 DYNAMIC FLEX FATIGUE TEST FOR FOAM AND FIBER PADS CONSTANT LOAD METHOD Method A Figure 1 Page 7 of 10 Copynght02001, Ford Global Technologies, Inc FORD LABORATORY TEST METHOD BO 012-04 DYNAM
41、IC FLEX FATIGUE TEST FOR FOAM AND FIBER PADS CONSTANT LOAD METHOD Method A Figure 2 Page 8 of 10 Copynght02001, Ford Global Technologies, Inc FORD LABORATORY TEST METHOD BO 012-04 Pivot points are attached to motor driven 2“ shaped metal bar DYNAMIC FLEX FATIGUE TEST FOR FOAM AND FIBER PADS CONSTANT
42、 LOAD METHOD Method A METHOD OF WEIGHING ROLLER FOR CONSTANT LOAD FATIGUE OF URETHANE FOAM Cotton Cord P Weight Loading Tray fl Force Gage reads 37-1/2 Ibs. (1 67 Nj for 15 by 15 in. (380 by 380 mmj foam sample when arms are horizontal (30 Ibs. 133 N for 12 by 15 in, (305 by 380 mm) sample). Roller
43、Figure 3 Page 9 of 10 Copynght02001, Ford Global Technologies, Inc FORD LABORATORY TEST METHOD BO 012-04 DYNAMIC FLEX FATIGUE TEST FOR FOAM AND FIBER PADS CONSTANT LOAD METHOD Attachment of the simulated heel for constant load fatigue of carpet underlayment. Method B Pivot points are attached to mot
44、or driven “Z“ sharied metal 65 f 2 Ib. load (289 +- 9 N) With carriage held horizontal to the base platen. Contact Surface Finish 30-60 Microinch I inch radius (25 mm) SIMULATED HEEL Material: CAE 1030 CD or Equiv. 4 in. long x 2 in. diameter (I O0 x 50 mm) I in. long threaded bit 3/8 NC (25 mm) Figure 4 Page 10 of 10 Copynght02001, Ford Global Technologies, Inc
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