Society of Automotive Engineers (SAE) Recommended Practice J211/1 Rev. MAR 95, Instrumentation for Impact Tests-Part 1—Electronic Instrumentation, is incorporated by reference in § 587.15 in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. A copy may be obtained from SAE at Society of Automotive Engineers, Inc., 400 Commonwealth Drive, Warrendale, PA 15096. A copy of the material may be inspected at NHTSA's Docket Section, 400 Seventh Street, S.W., room 5109, Washington, DC, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

The offset deformable barrier is comprised of two elements: a fixed rigid barrier and a deformable face (Figure 1). The fixed rigid barrier is adequate to not deflect or displace more than 10 mm during the vehicle impact. The deformable face consists of aluminum honeycomb and aluminum covering.

The dimensions of the deformable face are illustrated in Figure 1 of this subpart. The dimensions and materials of the individual components are listed separately below. All dimensions allow a tolerance of ±2.5 mm (0.1 in) unless otherwise specified.

(a) Main honeycomb block.

(1) Dimensions. The main honeycomb block has a height of 650 mm (25.6 in) (in the direction of honeycomb ribbon axis), a width of 1,000 mm (39.4 in), and a depth of 450 mm (17.7 in)(in the direction of honeycomb cell axis).

(2) Material. The main honeycomb block is constructed of the following material. The honeycomb is manufactured out of aluminum 3003, with a foil thickness of 0.076 mm (0.003 in) ±0.004 mm (0.002 in) a cell size of 19.14 mm (0.75 in), a density of 28.6 kg/m 3 (1.78 lb/ft 3) ±2kg/m 3 (0.25 1b/ft 3), and a crush strength of 0.342 MPa (49.6 psi) + 0%−10%, measured in accordance with the certification procedure described in § 587.15.

(b) Bumper element honeycomb.

(1) Dimensions. The bumper element honeycomb has a height of 330 mm (13 in)(in the direction of honeycomb ribbon axis), a width of 1,000 mm (39.4 in), and a depth of 90 mm (3.5 in) (in the direction of honeycomb cell axis).

(2) Material. The bumper element honeycomb is constructed of the following material. The honeycomb is manufactured out of aluminum 3003, with a foil thickness of 0.076 mm (0.003 in) ±0.004 mm (0.0002 in), a cell size of 6.4 mm (0.25 in) ±1 mm (0.040 in), a density of 82.6 kg/m 3 (5.15 lb/ft 3) ±3 kg/m 3 (0.19 lb/ft 3), and a crush strength of 1.711 MPa (248 psi) + 0% −10%, measured in accordance with the certification procedure described in § 587.14.

(c) Backing sheet.

(1) Dimensions. The backing sheet has a height of 800 mm (31.5 in), a width of 1,000 mm (39.4 in), and a thickness of 2.0 mm (0.08 in) ±0.1 mm (0.004 in).

(2) Material. The backing sheet is manufactured out of aluminum 5251/5052.

(d) Cladding sheet.

(1) Dimensions. The cladding sheet of the main honeycomb block has a total length of 1,700 mm (66.9 in), a width of 1,000 mm (39.4 in), and a thickness of 0.81 mm (0.03 in) ±0.07 mm (0.003 in). It is shaped as indicated in Figure 1.

(2) Material. The cladding sheet of the main honeycomb block is manufactured out of aluminum 5251/5052.

(e) Bumper element honeycomb facing sheet.

(1) Dimensions. The bumper facing sheet has a height of 330 mm (13 in), a width of 1,000 mm (39.4 in), and a thickness of 0.81 mm (0.03 in) ±0.07 mm (0.003 in).

(2) Material. The bumper element honeycomb facing sheet is manufactured out of aluminum 5251/5052.

(f) Adhesive. The adhesive used throughout is a two-part polyurethane. (such as Ciba-Geigy XB5090/1 resin with XB5304 hardener, or equivalent).

The following procedure is used to ascertain the crush strength of the main honeycomb block and the bumper element honeycomb, as specified in §§ 587.14(a)(2) and 587.14(b)(2).

(a) Sample locations. To ensure uniformity of crush strength across the whole of the deformable face, 8 samples are taken from 4 locations evenly spaced across the honeycomb material. Seven of these 8 samples must meet the crush strength requirements when tested in accordance with the following sections. The location of the samples depends on the size of the honeycomb material being tested. Four samples, each measuring 300 mm (11.8 in) × 300 mm (11.8 in) × 25 mm (1 in) thick are cut from the honeycomb material. (See Figure 2 for how to locate these samples on two different sizes of honeycomb material.) Each of these larger samples is cut into samples of the size specified in § 587.15(b). Verification is based on the testing of two samples from each of the four locations. The other two samples are retained for future verification, if necessary.

(b) Sample size. Samples of the following size are used for testing. The length is 150 mm (5.9 in) ±6 mm (0.24 in), the width is 150 mm (5.9 in) ±6 mm (0.24 in), and the thickness is 25 mm (1 in) ±2 mm (0.08 in). The walls of incomplete cells around the edge of the sample are trimmed as follows (See Figure 3). In the width (“W”) direction, the fringes (“f”) are no greater than 1.8 mm (0.07 in); in the length (“L”) direction, the fringes (“e”) are at least half the length of one bonded cell wall (“d”) (in the ribbon direction).

(c) Area measurement. The length of the sample is measured in three locations, 12.7 mm (0.5 in) from each end and in the middle, and recorded as L1, L2, and L3 (Figure 3). In the same manner, the width is measured and recorded as W1, W2, and W3 (Figure 3). These measurements are taken on the centerline of the thickness. The crush area is then calculated as:

(d) Crush rate and distance. The sample is crushed at a rate of not less than 5.1 mm/min (0.2 in/ min) and not more than 7.6 mm/min (0.29 in/min). The minimum crush distance is 16.5 mm (0.65 in). Force versus deflection data are collected in either analog or digital form for each sample tested. If analog data are collected, a means of converting the data to digital data must be made available. All digital data are collected at a rate consistent with SAE Recommended Practice J211/1 Rev. MAR 95 (see § 587.12).

(e) Crush strength determination. Ignore all data prior to 6.4 mm (0.25 in) of crush and after 16.5 mm (0.65 in) of crush. Divide the remaining data into three sections or displacement intervals (n = 1, 2, 3) (see Figure 4) as follows. Interval one is from 6.4-9.7 mm (0.25-0.38 in) deflection, inclusive. Interval two is from 9.7-13.2 mm (0.38-0.52 in) deflection, exclusive. Interval three is from 13.2-16.5 mm (0.52-0.65 in) deflection, inclusive. Find the average for each section as follows:

(f) Sample crush strength specification. For a honeycomb sample to meet crush strength requirements, the following condition must be met. For the 0.342 MPa (49.6 psi) material, the strength must be equal to or greater than 0.308 MPa (45 psi) but less than or equal to 0.342 MPa (49.6 psi) for all three compression intervals. For the 1.711 MPa (248 psi) material the strength must be equal to or greater than 1.540 MPa (223 psi) but less than or equal to 1.711 MPa (248 psi) for all three compression intervals.

(g) Testing hardware. (1) The hardware used to verify crush strength is capable of applying a load of 13.3 kN (3,000 lb), over at least a 16.5 mm (0.65 in) stroke. The crush rate is constant and known. To ensure that the load is applied to the entire sample, the top and bottom crush plates are no smaller than 165 mm by 165 mm (6.5 in × 6.5 in). The engaging surfaces of the crush plates have a roughness approximately equivalent to 60 grit sandpaper. The bottom crush plate is marked to ensure that the applied load is centered on the sample.

(2) The crush plate assemblies have an average angular rigidity (about axes normal to the direction of crush) of at least 1017 Nm/deg (750 ft-lb/deg), over the range of 0 to 203 Nm (0 to 150 ft-lb) applied torque.

Immediately before bonding, aluminum sheet surfaces to be bonded are thoroughly cleaned using a suitable solvent, such as 1-1-1 Trichloroethane. This is carried out at least twice and more often if required to eliminate grease or dirt deposits. The cleaned surfaces are abraded using 120 grit abrasive paper. Metallic/silicon carbide abrasive paper is not to be used. The surfaces are thoroughly abraded and the abrasive paper changed regularly during the process to avoid clogging, which could lead to a polishing effect. Following abrading, the surfaces are thoroughly cleaned again, as above. In total, the surfaces are solvent-cleaned at least four times. All dust and deposits left as a result of the abrading process are removed, as these can adversely affect bonding. The adhesive is applied to one surface only, using a ribbed rubber roller. In cases where honeycomb is to be bonded to aluminum sheet, the adhesive is applied to the aluminum sheet only. A maximum pressure of 0.5 kg/m 2 (11.9 lb/ft 2) is applied evenly over the surface, giving a maximum film thickness of 0.5 mm (0.02 in).

(a) The main honeycomb block is bonded to the backing sheet with adhesive such that the cell axes are perpendicular to the sheet. The cladding sheet is adhesively bonded to the front surface of the main honeycomb block. The top and bottom surfaces of the cladding sheet are not bonded to the main honeycomb block but are positioned close to it. The cladding sheet is adhesively bonded to the backing sheet at the mounting flanges. The bumper element honeycomb is adhesively bonded to the front of the cladding sheet such that the cell axes are perpendicular to the sheet. The bottom of the bumper element honeycomb is flush with the bottom surface of the cladding sheet. The bumper facing sheet is adhesively bonded to the front of the bumper element honeycomb.

(b) The bumper element honeycomb is divided into three equal sections by means of two horizontal slots. These slots are cut through the entire depth of the bumper element and extend the whole width of the bumper. The slots are cut using a saw; their width is the width of the blade used which do not exceed 4.0 mm (0.16 in).

(c) Clearance holes for mounting the deformable face are drilled in the cladding sheet mounting flanges (shown in Figure 5). The holes are 20 mm (0.79 in) in diameter. Five holes are drilled in the top flange at a distance of 40 mm (1.57 in) from the top edge of the flange and five holes in the bottom flange at a distance of 40 mm (1.6 in) from the bottom edge of the flange. The holes are spaced at 100 mm (3.9 in), 300 mm (11.8 in), 500 mm (19.7 in), 700 mm (27.5 in), 900 mm (35.4 in) horizontally, from either edge of the barrier. All holes are drilled within ±1 mm (0.04 in) of the nominal distances.

(a) The fixed rigid barrier has a mass of not less than 7 × 10 4 kg (154,324 lb).

(b) The height of the fixed rigid barrier is at least as high as the highest point on the vehicle at the intersection of the vertical transverse plane tangent to the forwardmost point of both front tires, when the tires are parallel to the longitudinal centerline of the vehicle, and the vertical plane through the longitudinal centerline of the vehicle.

(a) The deformable face is rigidly attached to the edge of the fixed rigid barrier or to some rigid structure attached thereto. The front of the fixed rigid barrier to which the deformable face is attached is flat (continuous over the height and width of the face and vertical ±1 degree and perpendicular ±1 degree to the axis of the run-up track). The edge of the deformable face is aligned with the edge of the fixed rigid barrier appropriate for the side of the vehicle to be tested.

(b) The deformable face is attached to the fixed rigid barrier by means of ten bolts, five in the top mounting flange and five in the bottom, such that the bottom of the bumper element honeycomb is 200 mm (7.8 in) ±15 mm (0.6 in) from the ground. These bolts are at least 8 mm (0.3 in) in diameter. Steel clamping strips are used for both the top and bottom mounting flanges (Figure 1). These strips are 60 mm (2.4 in) high and 1000 mm (39.4 in) wide and have thickness of at least 3 mm (0.12 in). Five clearance holes of 20 mm (0.8 in) diameter are drilled in both strips to correspond with those in the mounting flange on the deformable face cladding sheet (see § 586.17(c)).