Abstract：
Creep-associated changes in disc bulging and axial strains are essential for the research and development of mechano-bionic biomaterials and have been assessed in various ways in ex vivo creep studies. Nonetheless, the reported methods for measurement were limited by location inaccuracy, a lack of synchronousness, and destructiveness. To this end, this study focuses on the accurate, synchronous, and noninvasive assessment of bugling and strains using the 3D digital image correlation (3D-DIC) system and the impact of creep on them. After a preload of 30 min, the porcine cervical discs were loaded with different loads for 4 h of creep. Axial strains and lateral bulging of three locations on the discs were synchronously measured. The three-parameter solid model and the newly proposed horizontal asymptote model were used to fit the acquired data. The results showed that the load application reduced disc strains by 6.39% under 300 N, 11.28% under 400 N, and 12.59% under 500 N. Meanwhile, the largest protrusion occurred in the middle of discs with a bugling of 1.50 mm, 1.67 mm, and 1.87 mm. Comparison of the peer results showed that the 3D-DIC system could be used in ex vivo biomechanical studies with reliability and had potential in the assessment of the mechanical behavior of novel biomaterials. The phenomenon of the largest middle protrusion enlightened further the strength of spinal implants in this area. The mathematical characterizations of bulging and strains under different loads yielded various model parameters, which are prerequisites for developing implanted biomaterials.
摘要：
椎间盘膨出和轴向应变的蠕变相关变化对于机械仿生生物材料的研究和开发至关重要，并且在离体蠕变研究中以各种方式进行了评估。尽管如此，报告的测量方法受到位置不准确的限制，缺乏同步，和破坏性。为此,这项研究的重点是准确的，同步,以及使用3D数字图像相关（3D-DIC）系统以及蠕变对它们的影响进行无创性评估。预加载30分钟后，用不同的负荷加载猪颈椎间盘4h。同步测量椎间盘上三个位置的轴向应变和横向隆起。使用三参数实体模型和新提出的水平渐近线模型来拟合获得的数据。结果表明，在300N下，施加载荷可使椎间盘应变降低6.39％，在400N下11.28%，和12.59%低于500N。同时，最大的突起出现在圆盘的中间，发出1.50毫米的嗡嗡声，1.67mm,和1.87毫米。对同行结果的比较表明，3D-DIC系统可可靠地用于离体生物力学研究，并具有评估新型生物材料力学行为的潜力。最大的中间突出现象进一步启发了该区域脊柱植入物的强度。不同载荷下的膨胀和应变的数学表征产生了各种模型参数，这是开发植入式生物材料的先决条件。
