The present study aims to investigate the difference of the operation process and the significant mechanical properties between expert workers and beginner workers clearly. The influence of the performance of the carb...The present study aims to investigate the difference of the operation process and the significant mechanical properties between expert workers and beginner workers clearly. The influence of the performance of the carbon fiber reinforced plastic (CFRP) molds made by subjects with difference skill level was discussed. Subjects were allowed to choose their process and molding tools. Subject A had 13 years,and subject B had 1 year of professional experience.The time spent usage of tools and process was recorded by a video camera used for analysis and comparison. Mechanical properties assessed in this study include tensile,compressive and Izod impact properties. The working time analysis shows that subject A needs short time for each process. On the other hand,subject B takes twice time to work for each process compared with subject A. From the surface and cross-section observation, it was found that the molding made by subject B had wrinkles all over and the disorderly inter-layer direction; on the contrary,the wrinkles on the molding surface of subject A are barely,and the inter-layer direction of which are more orderly. The results of tensile and Izod impact tests show that the surface winkles have little influence on the mechanical properties of the molding. According to the compression test and failure structure analysis in edge corner part,it was found that it had a great influence on the compression mechanical properties of the sample belonging to different subjects with different experience.展开更多
Effects of the processing methods on the mechanical properties of treated bagasse fibre reinforced epoxy composite were evaluated. The composite materials were processed by employing hand lay-up and compression mouldi...Effects of the processing methods on the mechanical properties of treated bagasse fibre reinforced epoxy composite were evaluated. The composite materials were processed by employing hand lay-up and compression moulding methods and fibres were treated with NaOH solution. The composite samples were subjected to tensile, flexural and impact tests. Based on the findings, compression moulding method produced better mechanical properties compared to the composites manufactured by hand lay-up method. The results showed that the tensile strength and Young’s modulus of the samples produced by compression moulding method increased by 77 percent and 47 percent respectively (at optimal fibre loading) compared to those produced by the hand lay-up method. The results also showed noticeable improvements in the impact strength of the material produced by compression moulding method, with impact strength of 11.5 kJ/m2 against the samples produced by hand lay-up method, with impact strength of 7 kJ/m2.展开更多
包裹体积测量是物流计费的重要环节.针对快递网点和快递员上门收件等场景中对包裹体积现场快速测量的需求,提出一种基于RGB-D(red green blue-depth)相机的手持式包裹体积测量方法.首先,使用RGB-D相机获得场景初始点云,对初始点云预处...包裹体积测量是物流计费的重要环节.针对快递网点和快递员上门收件等场景中对包裹体积现场快速测量的需求,提出一种基于RGB-D(red green blue-depth)相机的手持式包裹体积测量方法.首先,使用RGB-D相机获得场景初始点云,对初始点云预处理后得到包裹点云,并提取包裹的两个特征平面.其次,对点云平面进行坐标变换,针对坐标变换后点云数据的非均匀性问题,采用基于八叉树的体素滤波算法对点云进行下采样及初步均匀化处理,并提出一种点云空洞填补算法修复体素滤波后点云中的空洞,从而得到两组分布均匀的包裹特征平面点云.最后,利用两组特征平面点云的坐标求取包裹体积.实验结果表明:测量结果的重复性相对误差小于1.6%,在不大于80 cm的拍摄距离内体积测量相对误差小于3.2%,满足物流现场高精度、低成本测量的需求.展开更多
文摘The present study aims to investigate the difference of the operation process and the significant mechanical properties between expert workers and beginner workers clearly. The influence of the performance of the carbon fiber reinforced plastic (CFRP) molds made by subjects with difference skill level was discussed. Subjects were allowed to choose their process and molding tools. Subject A had 13 years,and subject B had 1 year of professional experience.The time spent usage of tools and process was recorded by a video camera used for analysis and comparison. Mechanical properties assessed in this study include tensile,compressive and Izod impact properties. The working time analysis shows that subject A needs short time for each process. On the other hand,subject B takes twice time to work for each process compared with subject A. From the surface and cross-section observation, it was found that the molding made by subject B had wrinkles all over and the disorderly inter-layer direction; on the contrary,the wrinkles on the molding surface of subject A are barely,and the inter-layer direction of which are more orderly. The results of tensile and Izod impact tests show that the surface winkles have little influence on the mechanical properties of the molding. According to the compression test and failure structure analysis in edge corner part,it was found that it had a great influence on the compression mechanical properties of the sample belonging to different subjects with different experience.
文摘Effects of the processing methods on the mechanical properties of treated bagasse fibre reinforced epoxy composite were evaluated. The composite materials were processed by employing hand lay-up and compression moulding methods and fibres were treated with NaOH solution. The composite samples were subjected to tensile, flexural and impact tests. Based on the findings, compression moulding method produced better mechanical properties compared to the composites manufactured by hand lay-up method. The results showed that the tensile strength and Young’s modulus of the samples produced by compression moulding method increased by 77 percent and 47 percent respectively (at optimal fibre loading) compared to those produced by the hand lay-up method. The results also showed noticeable improvements in the impact strength of the material produced by compression moulding method, with impact strength of 11.5 kJ/m2 against the samples produced by hand lay-up method, with impact strength of 7 kJ/m2.
文摘包裹体积测量是物流计费的重要环节.针对快递网点和快递员上门收件等场景中对包裹体积现场快速测量的需求,提出一种基于RGB-D(red green blue-depth)相机的手持式包裹体积测量方法.首先,使用RGB-D相机获得场景初始点云,对初始点云预处理后得到包裹点云,并提取包裹的两个特征平面.其次,对点云平面进行坐标变换,针对坐标变换后点云数据的非均匀性问题,采用基于八叉树的体素滤波算法对点云进行下采样及初步均匀化处理,并提出一种点云空洞填补算法修复体素滤波后点云中的空洞,从而得到两组分布均匀的包裹特征平面点云.最后,利用两组特征平面点云的坐标求取包裹体积.实验结果表明:测量结果的重复性相对误差小于1.6%,在不大于80 cm的拍摄距离内体积测量相对误差小于3.2%,满足物流现场高精度、低成本测量的需求.
