背景:发育性髋关节发育不良常易导致患儿肢体畸形,其诊疗的相关研究已逐渐明确;近来有限元法因其优势在发育性髋关节发育不良的相关研究中受到学者重视。目的:通过文献检索综述有限元法在儿童发育性髋关节发育不良及治疗中的研究进展,...背景:发育性髋关节发育不良常易导致患儿肢体畸形,其诊疗的相关研究已逐渐明确;近来有限元法因其优势在发育性髋关节发育不良的相关研究中受到学者重视。目的:通过文献检索综述有限元法在儿童发育性髋关节发育不良及治疗中的研究进展,分析总结其优势与不足,并探讨未来进一步研究的方向及应用前景。方法:应用计算机在Pub Med、SCI、CBM和中国知网数据库中检索2014年1月至2023年11月发表的相关文献,以“developmental dysplasia(dislocation) of the hip,dysplasia of the hip,finite element analysis(method),pavlik harness,fixation in herringbone position,biomechanics,pelvic osteotomies,pemberton,salter,dega,periacetabular osteotomy,children”为英文检索词,以“发育性髋关节发育不良,发育性髋关节脱位,髋关节发育不良,儿童,有限元,Pavlik吊带,人字型固定,生物力学,骨盆截骨术,髋臼周围截骨术”为中文检索词,同时纳入少量远期文献,通过筛选最终纳入62篇文献进行分析。结果与结论:(1)儿童发育性髋关节发育不良髋关节力学环境异常,髋臼内部压力不均匀、应力增大并集中,关节接触面积减小,股骨颈局部应力集中;(2)在Pavlik吊带及人字型固定位患髋力学环境改善,集中的高应力区域消失,关节接触面积增加,但外展角度过大会导致髋臼及股骨头外侧应力增加;(3)骨盆截骨术治疗后髋关节及骶髂关节应力环境得到改善,3种截骨术没有单一的铰链,其应力负载部位因患儿年龄而存在差异;(4)髋臼周围截骨术治疗后关节接触压力接近正常,而非球形股骨头者恢复困难;(5)术后X射线片表现不能说明关节接触力学达到最佳;(6)提示利用有限元法可以获得体内无法测量的信息,其在虚拟环境中操作不受时间和伦理的限制;能直观地看到正常与发育性髋关节发育不良患者髋关节应力变化的区域,从力学角度说明治疗的有效性,为需要截骨手术治疗的患者建立特定的有限元模型、量身定做手术计划;发育性髋关节发育不良的有限元建模及儿童髋关节材料特性参数尚无规范、统一的标准,由于有限元固有的局限性,目前还不能分析同时包含骨骼、软骨、韧带、肌肉等元素的模型;有限元分析操作难度较大,虽有优势但不具普适性,且目前的研究样本量较少,还需进一步扩大及验证。展开更多
Dielectric elastomer actuator （DEA） show promise for mechatronic applications due to the advantages of dielectric elastomer, such as lightweight, flexible, low cost, high strain, etc, and many configurations of DEAs...Dielectric elastomer actuator （DEA） show promise for mechatronic applications due to the advantages of dielectric elastomer, such as lightweight, flexible, low cost, high strain, etc, and many configurations of DEAs have been demonstrated. As a kind of linear actuator, cone DEAs are studied in some laboratory prototypes due to easy manufacturing, however, their performance have not been exploited fully. Based on the working principle of DEA, a four-bar linkage mechanism is designed to provide negative stiffness preload, which can increase displacement output of actuator （outer diameter 100 mm） to 17 mm. Three cone actuating units are assembled in parallel to enhance the maximum force output to 5.07 N. Loading experiments of actuator in forward and backward strokes are performed, the experimental results show that backward stroke has stronger actuating capability than forward stroke, accordingly application of actuator is recommended. Four factors rather than applied voltage, i.e., number of actuating units, pre-stretch ratio, inner diameter, and outer diameter, are determined as influencing factors for Taguchi method. Then the performance objectives of actuator, i.e., displacement output, maximum force output, and maximum work in backward stroke, are investigated based on L9（34） Taguchi orthogonal design. The mean signal-to-noise （S/N） ratio based on the larger-the-better criterion is calculated according to the acquired displacement and force output. Analytical results show that outer diameter has the most significant influence on displacement output, and maximum force out and work output are influenced most by number of actuating units. Inner diameter also has an important effect on the performance objectives of actuator, while pre-stretch ratio has the least influence. The proposed performance investigation is helpful for the design and application of cone actuator in mechatronic system.展开更多
文摘背景:发育性髋关节发育不良常易导致患儿肢体畸形,其诊疗的相关研究已逐渐明确;近来有限元法因其优势在发育性髋关节发育不良的相关研究中受到学者重视。目的:通过文献检索综述有限元法在儿童发育性髋关节发育不良及治疗中的研究进展,分析总结其优势与不足,并探讨未来进一步研究的方向及应用前景。方法:应用计算机在Pub Med、SCI、CBM和中国知网数据库中检索2014年1月至2023年11月发表的相关文献,以“developmental dysplasia(dislocation) of the hip,dysplasia of the hip,finite element analysis(method),pavlik harness,fixation in herringbone position,biomechanics,pelvic osteotomies,pemberton,salter,dega,periacetabular osteotomy,children”为英文检索词,以“发育性髋关节发育不良,发育性髋关节脱位,髋关节发育不良,儿童,有限元,Pavlik吊带,人字型固定,生物力学,骨盆截骨术,髋臼周围截骨术”为中文检索词,同时纳入少量远期文献,通过筛选最终纳入62篇文献进行分析。结果与结论:(1)儿童发育性髋关节发育不良髋关节力学环境异常,髋臼内部压力不均匀、应力增大并集中,关节接触面积减小,股骨颈局部应力集中;(2)在Pavlik吊带及人字型固定位患髋力学环境改善,集中的高应力区域消失,关节接触面积增加,但外展角度过大会导致髋臼及股骨头外侧应力增加;(3)骨盆截骨术治疗后髋关节及骶髂关节应力环境得到改善,3种截骨术没有单一的铰链,其应力负载部位因患儿年龄而存在差异;(4)髋臼周围截骨术治疗后关节接触压力接近正常,而非球形股骨头者恢复困难;(5)术后X射线片表现不能说明关节接触力学达到最佳;(6)提示利用有限元法可以获得体内无法测量的信息,其在虚拟环境中操作不受时间和伦理的限制;能直观地看到正常与发育性髋关节发育不良患者髋关节应力变化的区域,从力学角度说明治疗的有效性,为需要截骨手术治疗的患者建立特定的有限元模型、量身定做手术计划;发育性髋关节发育不良的有限元建模及儿童髋关节材料特性参数尚无规范、统一的标准,由于有限元固有的局限性,目前还不能分析同时包含骨骼、软骨、韧带、肌肉等元素的模型;有限元分析操作难度较大,虽有优势但不具普适性,且目前的研究样本量较少,还需进一步扩大及验证。
基金supported by National Natural Science Foundation of China (Grant No. 50975139, Grant No. 50605031)Provincial Natural Science Foundation of Jiangsu, China (Grant No. 2008395)+1 种基金Foundation of State Key Laboratory of Robotics, China (Grant No. RLO200912)China Postdoctoral Science Foundation (Grant No. 20080441319, Grant No. 200902684)
文摘Dielectric elastomer actuator （DEA） show promise for mechatronic applications due to the advantages of dielectric elastomer, such as lightweight, flexible, low cost, high strain, etc, and many configurations of DEAs have been demonstrated. As a kind of linear actuator, cone DEAs are studied in some laboratory prototypes due to easy manufacturing, however, their performance have not been exploited fully. Based on the working principle of DEA, a four-bar linkage mechanism is designed to provide negative stiffness preload, which can increase displacement output of actuator （outer diameter 100 mm） to 17 mm. Three cone actuating units are assembled in parallel to enhance the maximum force output to 5.07 N. Loading experiments of actuator in forward and backward strokes are performed, the experimental results show that backward stroke has stronger actuating capability than forward stroke, accordingly application of actuator is recommended. Four factors rather than applied voltage, i.e., number of actuating units, pre-stretch ratio, inner diameter, and outer diameter, are determined as influencing factors for Taguchi method. Then the performance objectives of actuator, i.e., displacement output, maximum force output, and maximum work in backward stroke, are investigated based on L9（34） Taguchi orthogonal design. The mean signal-to-noise （S/N） ratio based on the larger-the-better criterion is calculated according to the acquired displacement and force output. Analytical results show that outer diameter has the most significant influence on displacement output, and maximum force out and work output are influenced most by number of actuating units. Inner diameter also has an important effect on the performance objectives of actuator, while pre-stretch ratio has the least influence. The proposed performance investigation is helpful for the design and application of cone actuator in mechatronic system.
