Title 49

SECTION 572.77

572.77 Instrumentation.

§ 572.77 Instrumentation.

(a)(1) Test probe. For the head, thorax, and knee impact test, use a test probe that is rigid, of uniform density and weighs 10 pounds and 6 ounces, with a diameter of 3 inches; a length of 13.8 inches; and an impacting end that has a rigid flat right face and edge radius of 0.5 inches.

(2) The head and thorax assembly may be instrumented either with a Type A or Type B accelerometer.

(i) Type A accelerometer is defined in drawing SA 572 S1.

(ii) Type B accelerometer is defined in drawing SA 572 S2.

(b) Head accelerometers. (1) Install accelerometers in the head as shown in drawing SA 106C 001 sheet 1 using suitable spacers or adaptors as needed to affix them to the horizontal transverse bulkhead so that the sensitive axes of the three accelerometers intersect at the point in the midsagittal plane located 0.4 inches below the intersection of a line connecting the longitudinal center lines of the roll pins in either side of the dummy's head with the head's midsagittal plane.

(2) The head has three orthogonally mounted accelerometers aligned as follows:

(i) Align one accelerometer so that its sensitive axis is perpendicular to the horizontal bulkhead in the midsagittal plane.

(ii) Align the second accelerometer so that its sensitive axis is parallel to the horizontal bulkhead, and perpendicular to the midsagittal plane.

(iii) Align the third accelerometer so that its sensitive axis is parallel to the horizontal bulkhead in the midsagittal plane.

(iv) The seismic mass center for any of these accelerometers may be at any distance up to 0.4 inches from the axial intersection point.

(c) Thoracic accelerometers. (1) Install accelerometers in the thoracic assembly as shown in drawing SA 106C 001, sheet 1, using suitable spacers and adaptors to affix them to the frontal surface of the spine assembly so that the sensitive axes of the three accelerometers intersect at a point in the midsagittal plane located 0.95 inches posterior of the spine mounting surface, and 0.55 inches below the horizontal centerline of the two upper accelerometer mount attachment hole centers.

(2) The sternum-thoracic assembly has three orthogonally mounted accelerometers aligned as follows:

(i) Align one accelerometer so that its sensitive axis is parallel to the attachment surface in the midsagittal plane.

(ii) Align the second accelerometer so that its sensitive axis is parallel to the attachment surface, and perpendicular to the midsagittal plane.

(iii) Align the third accelerometer so that its sensitive axis is perpendicular to the attachment surface in the midsagittal plane.

(iv) The seismic mass center for any of these accelerometers may be at any distance up to 0.4 inches of the axial intersection point.

(d) Femur-sensing device. Install a force-sensing device SA 572-S10 axially in each femur shaft as shown in drawing SA 106C 072 and secure it to the femur assembly so that the distance measured between the center lines of two attachment bolts is 3.00 inches.

(e) Limb joints. Set the limb joints at lg, barely restraining the limb's weight when the limb is extended horizontally, and ensure that the force required to move the limb segment does not exceed 2g throughout the limb's range of motion.

(f) Recording outputs. Record the outputs of acceleration and force-sensing devices installed in the dummy and in the test apparatus specified in this part, in individual channels that conform to the requirements of SAE Recommended Practice J211, October 1988, with channel classes as set out in the following table C.

The mountings for sensing devices shall have no resonance frequency within a range of 3 times the frequency range of the applicable channel class.

---