ABSTRACT
Topology optimization (TO) is a powerful technique capable of finding the optimal layout of material and connectivity within a design domain. However, designs obtained by TO are usually geometrically complex. Such complex designs cannot be fabricated easily by conventional manufacturing methods. Therefore, additive manufacturing (AM), a free-form manufacturing technique, is extensively coupled with TO. Like most techniques, AM has its own limitations. Consequently, a range of additive manufacturing oriented topology optimization (AM oriented TO) algorithms were proposed to generate the topologies suitable for AM. Due to existing trade-off relationships in AM oriented TO, investigating multi-objective AM oriented TO seems essential to obtain more practical solutions. This paper provides a review on the recent developments of MOTO, AM oriented TO, and trade-off relationships that exist in AM oriented TO. This review paper also discusses the challenges and future trends in these topics. It is hoped that this review paper could inspire both academics and engineers to make a contribution towards bridging together MOTO and AM.
ABSTRACT
Nanostarches were successfully prepared by high speed jet (HSJ) after pretreatment of micronization. The nanostarches were obtained at the conditions of micronization treatment for 60min, and then one cycle at 240MPa of HSJ (188.1nm). Moreover, after HSJ treated for three cycles, the particle size could reach the level of nanometer materials (66.94nm). The physicochemical properties of nanostarches had been characterized. Rapid Visco-Analysis (RVA) showed that the viscosity of nanostarches significantly decreased compared with native tapioca starch and slightly decreased with increasing processing cycles of HSJ. Steady shear analysis indicated that all samples displayed pseudoplastic, shear-thinning behavior, while the flow curves of nanostarches were little impact by the processing cycles of HSJ. X-ray diffraction analysis showed that the complete destruction of tapioca starch crystalline structure was obtained after HSJ treatment. Molecular characteristics determination suggested that the degradation of amylopectin chains occurred after the treatment of micronization and HSJ, which was proved by the decrease of weight-average molar mass. The results demonstrated that nanostarches were obtained due to the breakdown of starch molecules. This study will provide useful information of the nanostarches for its potential industrial application.
