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A toolpath strategy for improving geometric accuracy in double-sided incremental sheet forming

Chinese Journal of Aeronautics 2023年第1期36卷 468-479页

作者： sattar ullah Xiaoqiang LI Peng XU Yanle LI Kai HAN Dongsheng LI School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Key Laboratory of High Efficiency and Clean Mechanical Manufacture Ministry of EducationSchool of Mechanical EngineeringShandong UniversityJinan 250061China

The double-sided incremental forming(DSIF)improved the process flexibility compared to other incremental sheet forming(ISF)processes.Despite the flexible nature,it faces the challenge of low geometric precision like ISF variants.In this work,two strategies are used to overcome this.First,a novel method is employed to determine the optimal support tool location for improving geometric precision.In this method,the toolpath oriented the tools to each other systematically in the circumferential direction.Besides,it squeezed the sheet by the same amount at the point of interest.The impacts of various support tool positions in the circumferential direction are evaluated for geometric precision.The results demonstrate that the support tool should support the master tool within 10°to its local normal in the circumferential direction to improve the geometric accuracy.Second,a two-stage process reduced the geometric error of the part by incrementally accommodating the springback error by artificially increasing the step size for the second stage.With the optimal support tool position and two-stage DSIF,the geometric precision of the part has improved significantly.The proposed method is compared to the best DSIF toolpath strategies for geometric accuracy,surface roughness,forming time,and sheet thickness fluctuations using grey relational analysis(GRA).It outperforms the other toolpath strategies including single-stage DSIF,accumulative double-sided incremental forming(ADSIF),and two-stage mixed double sided incre-mental forming(MDSIF).Our approach can improve geometric precision in complex parts by successfully employing the support tool and managing the springback incrementally.

关键词： incremental sheet forming double-sided incremental forming geometric accuracy springback grey relational analyses

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虚拟多工具渐进成形仿真及试验验证

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锻压技术 2023年第5期48卷 296-305页

作者：王雅欣许鹏 sattar ullah 张贺刚刘哨巡李小强阳晓军北京航空航天大学机械工程及自动化学院北京100191 航发智造(北京)科技有限公司北京100083 上海飞机制造有限公司上海201324 广州希鹏计算机科技有限公司广东广州510663

传统渐进成形仿真的时间长,难以有效指导实际工艺开发。基于国产自主研发的AI-FORM软件平台,开发了虚拟多工具算法,实现了渐进成形的快速仿真。通过进行方锥典型件的建模-轨迹设计-模拟-优化一体化仿真流程,对比了单工具和多工具仿真结... 详细信息

传统渐进成形仿真的时间长,难以有效指导实际工艺开发。基于国产自主研发的AI-FORM软件平台,开发了虚拟多工具算法,实现了渐进成形的快速仿真。通过进行方锥典型件的建模-轨迹设计-模拟-优化一体化仿真流程,对比了单工具和多工具仿真结果的轮廓精度、厚度差异及仿真时间差异,从而验证了虚拟多工具算法的高效性和可靠性。结合实际生产需要,将虚拟多工具算法应用于马鞍形连接件渐进成形工艺仿真中,通过特征分区以及曲线识别优化加工轨迹,对比实际试验件和仿真结果的截面轮廓及特征区厚度,证明了轨迹优化设计的合理性及必要性,并进一步验证了虚拟多工具算法预测实际零件成形的准确性。

关键词：渐进成形虚拟多工具算法轨迹优化截面轮廓精度特征区厚度

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Comparative study for machine learning classifier recommendation to predict political affiliation based on online

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CAAI Transactions on Intelligence Technology 2021年第3期6卷 251-264页

作者： Hayat ullah Bashir Ahmad Iqra Sana Anum sattar Aurangzeb Khan Saima Akbar Muhammad Zubair Asghar Department of Computer Science Qurtuba University of Science and TechnologyDera Ismail KhanKhyber PakhtunkhwaPakistan Institute of Computing and Information Technology Gomal UniversityDera Ismail KhanKhyber PakhtunkhwaPakistan Deptartment of Computer Science University of Science and TechnologyBannuKhyber PakhtunkhwaPakistan

In the current era of social media,different platforms such as Twitter and Facebook have frequently been used by leaders and the followers of political parties to participate in political events,campaigns,and elections.The acquisition,analysis,and presentation of such content have received considerable attention from opinion-mining researchers.For this purpose,different supervised and unsupervised techniques have been used.However,they have produced less efficient results,which need to be improved by incorporating additional classifiers with the extended data sets.The authors investigate different su-pervised machine learning classifiers for classifying the political affiliations of users.For this purpose,a data set of political reviews is acquired from Twitter and annotated with different polarity classes.After pre-processing,different machine learning classifiers like K-nearest neighbor,naïve Bayes,support vector machine,extreme gradient boosting,and others,are applied.Experimental results illustrate that support vector machine and extreme gradient boosting have shown promising results for predicting political affiliations.

关键词： boosting classifier extreme

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Biochar Application Improves the Drought Tolerance in Maize Seedlings

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Phyton-International Journal of Experimental Botany 2019年第4期88卷 379-388页

作者： A.sattar A.Sher M.Ijaz M.Irfan M.Butt T.Abbas S.Hussain A.Abbas M.S.ullah M.A.Cheema College of Agriculture Bahauddin Zakariya University Bahadur Sub-CampusLayyah31200Pakistan Department of Agronomy Faculty of Agriculture Science and Technology Bahauddin Zakariya UniversityMultan60800Pakistan Faculty of Pharmaceutical Sciences Government College UniversityFaisalabad38000Pakistan School of Science and the Environment Grenfell Campus Memorial University of NewfoundlandCorner Brook2000A2H 5G4Canada

Application of biochar to agricultural soils is mostly used to improve soil fertility.Experimental treatments were comprised of two factors:i)drought at two level,i.e.,80%and 40%water holding capacity(WHC)which was maintained on gravimetric basis ii)three levels of biochar i.e.,control,2 t ha^(-1) and 4 t ha^(-1) added to soil.Experimentation was done to examine potential of biochar application to enhance the growth attributes,water relations,photosynthetic pigments and antioxidants activities in maize(Zea mays L.)seedlings.Results of study revealed that biochar application increased the growth qualities(total seedlings biomass,dry weight of shoot and root,shoot length and root length).In addition;contents of photosynthetic pigments(chlorophyll a,b,a+b and a/b),water relation(relative water contents,turgor potential,osmotic potential and water potential)were improved significantly due to addition of biochar.Addition of 4 t ha^(-1) biochar led to significant rise activity of enzymatic antioxidant catalase(CAT),superoxide dismutase(SOD)and peroxidase(POD)in leaf of maize seedling sunder drought as well as well watered circumstances.However,biochar applied at the rate 4 t ha^(-1) improved the all the physiological and biochemical attributes in maize seedlings under drought.From the results it was concluded that biochar application is an efficient way to alleviate adverse effect of drought stress on maize.In drought prone areas,long term impacts of biochar on production of maize and properties of soil could be recommended as upcoming shove.

关键词： Antioxidants biochar drought stress water relations chlorophyll contents

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