---
kind: "section"
citation: "49 C.F.R. § 572.34"
title: "49"
number: "572.34"
heading: "Thorax."
url: "https://uscodex.org/cfr/49/572.34"
---

# §572.34. Thorax.

- (a) The thorax consists of the upper torso assembly in drawing 78051-89, revision K and shall conform to each of the drawings subtended therein.
- (b) When impacted by a test probe conforming to [§ 572.36(a)](/cfr/49/572.36.md?p=a) at 22 fps ±0.40 fps in accordance with [paragraph (c)](#c) of this section, the thorax of a complete dummy assembly (78051-218, revision U, without shoes, shall resist with a force of 1242.5 pounds ±82.5 pounds measured by the test probe and shall have a sternum displacement measured relative to spine of 2.68 inches ±0.18 inches. The internal hysteresis in each impact shall be more than 69% but less than 85%. The force measured is the product of pendulum mass and deceleration.
- (c) **Test procedure.**
  - (1) Soak the test dummy in an environment with a relative humidity from 10% to 70% until the temperature of the ribs of the test dummy have stabilized at a temperature between 69 degrees F and 72 degrees F.
  - (2) Seat the dummy without back and arm supports on a surface as shown in Figure 23, and set the angle of the pelvic bone at 13 degrees plus or minus 2 degrees, using the procedure described in S11.4.3.2 of Standard No. 208 ([§ 571.208](/cfr/49/571.208.md) of this chapter).
  - (3) Place the longitudinal centerline of the test probe so that it is .5 ±.04 in. below the horizontal centerline of the No. 3 Rib (reference drawing number 79051-64, revision A-M) as shown in Figure 23.
  - (4) Align the test probe specified in [§ 572.36(a)](/cfr/49/572.36.md?p=a) so that at impact its longitudinal centerline coincides within .5 degree of a horizontal line in the dummy's midsagittal plane.
  - (5) Impact the thorax with the test probe so that the longitudinal centerline of the test probe falls within 2 degrees of a horizontal line in the dummy midsagittal plane at the moment of impact.
  - (6) Guide the probe during impact so that it moves with no significant lateral, vertical, or rotational movement.
  - (7) Measure the horizontal deflection of the sternum relative to the thoracic spine along the line established by the longitudinal centerline of the probe at the moment of impact, using a potentiometer (ref. drawing 78051-317, revision A) mounted inside the sternum as shown in drawing 78051-89, revision I.
  - (8) Measure hysteresis by determining the ratio of the area between the loading and unloading portions of the force deflection curve to the area under the loading portion of the curve.

## Notes

### Amendments

[51 FR 26701, July 25, 1986, as amended at 53 FR 8765, Mar. 17, 1988; 62 FR 27518, May 20, 1997; 63 FR 53851, Oct. 7, 1998]

### Source

Source: 51 FR 26701, July 25, 1986, unless otherwise noted.

### Authority

Authority: 49 U.S.C. 322, 30111, 30115, 30117 and 30166; delegation of authority at 49 CFR 1.95

### Amendments

[51 FR 26701, July 25, 1986, as amended at 53 FR 8765, Mar. 17, 1988; 62 FR 27518, May 20, 1997; 63 FR 53851, Oct. 7, 1998]