Material Properties of Human Rib Cortical Bone from Dynamic Tension Coupon Testing

Abstract

The purpose of this study was to develop material properties of human rib cortical bone using dynamic tension coupon testing. This study presents 117 human rib cortical bone coupon tests from six cadavers, three male and three female, ranging in age from 18 to 67 years old. The rib sections were taken from the anterior, lateral, and posterior regions on ribs 1 through 12 of each cadaver's rib cage. The cortical bone was isolated from each rib section with a low speed diamond saw, and milled into dog bone shaped tension coupons using a small computer numerical control machine. A high-rate servo-hydraulic Material Testing System equipped with a custom slack adaptor, to provide constant strain rates, was used to apply tension loads to failure at an average rate of 0.5 strains/sec. The elastic modulus, yield stress, yield strain, ultimate stress, ultimate strain, and strain energy density were determined from the resulting stress versus strain curves. The overall average of all cadaver data gives an elastic modulus of 13.9 GPa, a yield stress of 93.9 MPa, a yield strain of 0.883 %, an ultimate stress of 124.2 MPa, an ultimate strain of 2.7 %, and a strain energy density of 250.1 MPa-strain. For all cadavers, the plastic region of the stress versus strain curves was substantial and contributed approximately 60 strain % to the overall response and over 80 strain % in the tests with the 18 year old cadaver. The rib cortical bone becomes more brittle with increasing age, shown by an increase in the modulus (p < 0.01) and a decrease in peak strain (p < 0.01). In contrast to

Construction and evaluation of thoracic injury risk curves for a finite element human body model in frontal car crashes

“…Also from a series of rib cortical bone coupon tests, Subit et al (2011) found an average ultimate tensile stress of 124.6 MPa. The first principal strain at 50% risk of rib fracture at the NFR2+ level obtained in the current study was 1.92%, which also compares favourably with the average ultimate strain of 1.05% reported by Subit et al (2011), and with the 2.6 reported by (Kemper et al, 2005(Kemper et al, , 2007. In conclusion, the stress and strain results at 50% risk of NFR2+ in this study are similar to the average stress and strain values in previous studies on human cortical bone.…”

“…This value is also comparable to the values reported in the literature. The average ultimate tensile stress in coupon tests of rib cortical bone reported by Kemper et al (2005Kemper et al ( , 2007 was 127.5 MPa. Also from a series of rib cortical bone coupon tests, Subit et al (2011) found an average ultimate tensile stress of 124.6 MPa.…”

Reducing Chest Injuries in Automobile Collisions: Rib Fracture Timing and Implications for Thoracic Injury Criteria

“…Numerous authors have shown that the response and injury tolerance of the thorax can vary substantially between individuals due to differences in age, thoracic geometry, rib angle, BMD, and material properties. 24,29,30,52 Moreover, the female PMHS in this study was osteoporotic and had two pre-existing, non-displaced rib fractures. Both of these conditions would lower the force response and likely resulted in earlier rib fractures when compared to healthy younger females.…”

“…For comparison with the standard population, the bone mineral density (BMD) of each PMHS was determined by the Osteogram technique. 18,23,24,45 For this technique, the left hand of each PMHS was X-rayed next to an aluminum calibration wedge. The X-ray was then processed by CompuMed Incorporated (CompuMed, Inc., Los Angeles, CA) to obtain the BMD, T score, and Z score for each subject.…”

“…Dynamic tension and threepoint bending tests on isolated human rib cortical bone coupons have been conducted by researchers in order to quantify the material and failure properties of human ribs. 24,25,45 The structural response of human ribs, which is a function of both the material properties and geometry, has been investigated by numerous authors by performing component level testing on rib sections in three-point bending. 6,16,25,41,43,51 Other studies have investigated the structural response of individual whole ribs in dynamic anterior-posterior loading.…”