Porous Ti6Al4V constructs have been developed to replace mandibular bone, however the flexural fatigue properties of these constructs must first be assessed. In this study, porous constructs were built by selective laser melting (SLM) and subjected to cyclic flexural loading using a three-point bending setup and a servo-hydraulic Instron machine. Maximum flexural stress was plotted against the number of cycles. Also, numerical models were developed to predict the fatigue strength of porous constructs. These models were validated using experimental test data and extended to account for bone ingrowth. Scanning electron microscopy was used to study the internal and surface structures of dynamically loaded constructs. We found that numerical models of the SLM-built constructs accurately predicted flexural fatigue strength within ≈10 % deviation. Numerical fatigue models and experimental tests demonstrated that fatigue strength of constructs were ≈30 % of their flexural yield strengths. Numerical models with bone ingrowth revealed that fatigue strength was doubled when compared to models without bone ingrowth. This may have been due to a damping effect of bone, resulting in reduction of fatigue failure. Overall, our study demonstrates the effectiveness of using numerical modeling in estimating the fatigue strength of SLM-built constructs intended for mandibular implant designs.

中文翻译：

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用于下颌重建的多孔 Ti6Al4V 结构的循环弯曲疲劳

多孔 Ti6Al4V 结构已被开发用于替代下颌骨，但必须首先评估这些结构的弯曲疲劳特性。在这项研究中，多孔结构通过选择性激光熔化 (SLM) 构建，并使用三点弯曲装置和伺服液压 Instron 机器承受循环弯曲载荷。绘制最大弯曲应力与循环次数的关系图。此外，还开发了数值模型来预测多孔结构的疲劳强度。这些模型使用实验测试数据进行了验证，并扩展到考虑骨骼向内生长的情况。扫描电子显微镜用于研究动态加载结构的内部和表面结构。我们发现，SLM 构建的结构的数值模型可以准确预测弯曲疲劳强度，偏差在 ≈10% 之内。数值疲劳模型和实验测试表明，结构的疲劳强度约为其弯曲屈服强度的 30%。具有骨向内生长的数值模型表明，与没有骨向内生长的模型相比，疲劳强度增加了一倍。这可能是由于骨骼的阻尼效应，导致疲劳失效的减少。总体而言，我们的研究证明了使用数值模型来估计用于下颌种植体设计的 SLM 构建结构的疲劳强度的有效性。