针对某机床结构薄弱件立柱的结构优化设计,提出了一种基于拓扑优化、筋板形式选择与布局以及尺寸优化的结构设计方法。首先利用有限元法(finite element analysis,FEA)对机床整机进行动力学分析,模态分析与谐响应分析结果表明立柱为影...针对某机床结构薄弱件立柱的结构优化设计,提出了一种基于拓扑优化、筋板形式选择与布局以及尺寸优化的结构设计方法。首先利用有限元法(finite element analysis,FEA)对机床整机进行动力学分析,模态分析与谐响应分析结果表明立柱为影响整机动态性能的关键结构件。然后以立柱结构为优化目标,对立柱进行拓扑优化,根据拓扑优化的材料分布情况设计了立柱的最优基本结构形式,再通过选择抗弯、抗扭刚度较好的W类型筋板进行布局与尺寸优化,得到了最终的立柱优化结构。最后对优化的立柱结构进行验证,分析结果表明:该结构设计方法有效地改善了整机的动态性能,在立柱质量减轻的前提下,优化后的整机前六阶固有频率均得到了不同程度的提高,其中一阶固有频率提高了10%以上;并且机床在x方向上的最大共振峰值下降了49.8%,y方向下降了70.1%,z方向下降了66.2%。展开更多
Achyranthes bidentata polysaccharides (ABPS), water_soluble polysaccharides, isolated from the roots of Achyranthes bidentata Bl. of Amaranthaceae family, was divided into four parts, named as Con.1, Con.2, Con....Achyranthes bidentata polysaccharides (ABPS), water_soluble polysaccharides, isolated from the roots of Achyranthes bidentata Bl. of Amaranthaceae family, was divided into four parts, named as Con.1, Con.2, Con.3 and Con.4, respectively, by chromatography on DEAE_Sepharose fast_flow column and Sephadex G_100 column in order. Con.1 was the constituent of high molecular weight and the other three were all of low molecular weight. Micro_Kjeldahl analysis showed that Con.1 contained 3.95% of nitrogen and neither did the other three parts. The antisenile effects of the four parts of ABPS were studied with Drosophila melanogaster. Results showed that Con.1 has no antisenile effect and all the others could significantly increase the average body weight by 3.85%-5.47% and significantly prolonged the average lifespan by 2.61%- 3.16% of D. melanogaster at the concentration of 2 or 5 mg/g (ABPS/medium).展开更多
文摘针对某机床结构薄弱件立柱的结构优化设计,提出了一种基于拓扑优化、筋板形式选择与布局以及尺寸优化的结构设计方法。首先利用有限元法(finite element analysis,FEA)对机床整机进行动力学分析,模态分析与谐响应分析结果表明立柱为影响整机动态性能的关键结构件。然后以立柱结构为优化目标,对立柱进行拓扑优化,根据拓扑优化的材料分布情况设计了立柱的最优基本结构形式,再通过选择抗弯、抗扭刚度较好的W类型筋板进行布局与尺寸优化,得到了最终的立柱优化结构。最后对优化的立柱结构进行验证,分析结果表明:该结构设计方法有效地改善了整机的动态性能,在立柱质量减轻的前提下,优化后的整机前六阶固有频率均得到了不同程度的提高,其中一阶固有频率提高了10%以上;并且机床在x方向上的最大共振峰值下降了49.8%,y方向下降了70.1%,z方向下降了66.2%。
文摘Achyranthes bidentata polysaccharides (ABPS), water_soluble polysaccharides, isolated from the roots of Achyranthes bidentata Bl. of Amaranthaceae family, was divided into four parts, named as Con.1, Con.2, Con.3 and Con.4, respectively, by chromatography on DEAE_Sepharose fast_flow column and Sephadex G_100 column in order. Con.1 was the constituent of high molecular weight and the other three were all of low molecular weight. Micro_Kjeldahl analysis showed that Con.1 contained 3.95% of nitrogen and neither did the other three parts. The antisenile effects of the four parts of ABPS were studied with Drosophila melanogaster. Results showed that Con.1 has no antisenile effect and all the others could significantly increase the average body weight by 3.85%-5.47% and significantly prolonged the average lifespan by 2.61%- 3.16% of D. melanogaster at the concentration of 2 or 5 mg/g (ABPS/medium).
