Organic sheets made out of fiber-reinforced thermoplastics are able to make a crucial contribution to increase the lightweight potential of a design. They show high specific strength- and stiffness properties, good da...Organic sheets made out of fiber-reinforced thermoplastics are able to make a crucial contribution to increase the lightweight potential of a design. They show high specific strength- and stiffness properties, good damping characteristics and recycling capabilities, while being able to show a higher energy absorption capacity than comparable metal constructions. Nowadays, multi-material designs are an established way in the automotive industry to combine the benefits of metal and fiber-reinforced plastics. Currently used technologies for the joining of organic sheets and metals in large-scale production are mechanical joining technologies and adhesive technologies. Both techniques require large overlapping areas that are not required in the design of the part. Additionally, mechanical joining is usually combined with “fiber-destroying” pre-drilling and punching processes. This will disturb the force flux at the joining location by causing unwanted fiber- and inter-fiber failure and inducing critical notch stresses. Therefore, the multi-material design with fiber-reinforced thermoplastics and metals needs optimized joining techniques that don’t interrupt the force flux, so that higher loads can be induced and the full benefit of the FRP material can be used. This article focuses on the characterization of a new joining technology, based on the Cold Metal Transfer (CMT) welding process that allows joining of organic sheets and metals in a load path optimized way, with short cycle times. This is achieved by redirecting the fibers around the joining area by the insertion of a thin metal pin. The path of the fibers will be similar to paths of fibers inside structures found in nature, e.g. a knothole inside of a tree. As a result of the bionic fiber design of the joint, high joining strengths can be achieved. The increase of the joint strength compared to blind riveting was performed and proven with stainless steel and orthotropic reinforced composites in shear-tests based on the DIN EN ISO 14273. Every specimen joined with the new CMT Pin joining technology showed a higher strength than specimens joined with one blind rivet. Specimens joined with two or three pin rows show a higher strength than specimens joined with two blind rivets.展开更多
In this paper,to present a lightweight-developed front underrun protection device(FUPD)for heavy-duty trucks,plain weave carbon fiber reinforced plastic(CFRP)is used instead of the original high-strength steel.First,t...In this paper,to present a lightweight-developed front underrun protection device(FUPD)for heavy-duty trucks,plain weave carbon fiber reinforced plastic(CFRP)is used instead of the original high-strength steel.First,the mechanical and structural properties of plain carbon fiber composite anti-collision beams are comparatively analyzed from a multi-scale perspective.For studying the design capability of carbon fiber composite materials,we investigate the effects of TC-33 carbon fiber diameter(D),fiber yarn width(W)and height(H),and fiber yarn density(N)on the front underrun protective beam of carbon fiber compositematerials.Based on the investigation,a material-structure matching strategy suitable for the front underrun protective beam of heavy-duty trucks is proposed.Next,the composite material structure is optimized by applying size optimization and stack sequence optimization methods to obtain the higher performance carbon fiber composite front underrun protection beam of commercial vehicles.The results show that the fiber yarn height(H)has the greatest influence on the protective beam,and theH1matching scheme for the front underrun protective beamwith a carbon fiber composite structure exhibits superior performance.The proposed method achieves a weight reduction of 55.21% while still meeting regulatory requirements,which demonstrates its remarkable weight reduction effect.展开更多
以非线性数值计算为手段,对比分析缆索系统、加劲梁、桥塔及支承系统等结构系统,研究表明主跨3 500 m CFRP主缆悬索桥具有技术可行性。利用精细有限元结构仿真分析手段,对主跨3 500 m CFRP主缆悬索桥结构体系进行参数敏感性分析,研究结...以非线性数值计算为手段,对比分析缆索系统、加劲梁、桥塔及支承系统等结构系统,研究表明主跨3 500 m CFRP主缆悬索桥具有技术可行性。利用精细有限元结构仿真分析手段,对主跨3 500 m CFRP主缆悬索桥结构体系进行参数敏感性分析,研究结构参数对超大跨径悬索桥静、动力性能影响,结合结构系统数值模型分析研究,确定了主跨3 500 m CFRP主缆悬索桥最优结构体系。建立物理模型,进行CFRP主缆索股的锚固、滑移、弯折等理论分析及静载、疲劳试验研究。研发了可用于实桥的黏结性锚具,锚固效率系数达100%。验证了抗滑移、弯折性能,在鞍座处摩擦系数约0.5,在索夹处达0.331,在鞍座处的弯曲强度超过其抗拉强度的90%,在索夹处几乎不存在弯折问题。以研究成果为依据,进行了主跨3 500 m CFRP主缆悬索桥原型设计。展开更多
文摘Organic sheets made out of fiber-reinforced thermoplastics are able to make a crucial contribution to increase the lightweight potential of a design. They show high specific strength- and stiffness properties, good damping characteristics and recycling capabilities, while being able to show a higher energy absorption capacity than comparable metal constructions. Nowadays, multi-material designs are an established way in the automotive industry to combine the benefits of metal and fiber-reinforced plastics. Currently used technologies for the joining of organic sheets and metals in large-scale production are mechanical joining technologies and adhesive technologies. Both techniques require large overlapping areas that are not required in the design of the part. Additionally, mechanical joining is usually combined with “fiber-destroying” pre-drilling and punching processes. This will disturb the force flux at the joining location by causing unwanted fiber- and inter-fiber failure and inducing critical notch stresses. Therefore, the multi-material design with fiber-reinforced thermoplastics and metals needs optimized joining techniques that don’t interrupt the force flux, so that higher loads can be induced and the full benefit of the FRP material can be used. This article focuses on the characterization of a new joining technology, based on the Cold Metal Transfer (CMT) welding process that allows joining of organic sheets and metals in a load path optimized way, with short cycle times. This is achieved by redirecting the fibers around the joining area by the insertion of a thin metal pin. The path of the fibers will be similar to paths of fibers inside structures found in nature, e.g. a knothole inside of a tree. As a result of the bionic fiber design of the joint, high joining strengths can be achieved. The increase of the joint strength compared to blind riveting was performed and proven with stainless steel and orthotropic reinforced composites in shear-tests based on the DIN EN ISO 14273. Every specimen joined with the new CMT Pin joining technology showed a higher strength than specimens joined with one blind rivet. Specimens joined with two or three pin rows show a higher strength than specimens joined with two blind rivets.
基金supported by the Guangxi Science and Technology Plan and Project(Grant Numbers 2021AC19131 and 2022AC21140)Guangxi University of Science and Technology Doctoral Fund Project(Grant Number 20Z40).
文摘In this paper,to present a lightweight-developed front underrun protection device(FUPD)for heavy-duty trucks,plain weave carbon fiber reinforced plastic(CFRP)is used instead of the original high-strength steel.First,the mechanical and structural properties of plain carbon fiber composite anti-collision beams are comparatively analyzed from a multi-scale perspective.For studying the design capability of carbon fiber composite materials,we investigate the effects of TC-33 carbon fiber diameter(D),fiber yarn width(W)and height(H),and fiber yarn density(N)on the front underrun protective beam of carbon fiber compositematerials.Based on the investigation,a material-structure matching strategy suitable for the front underrun protective beam of heavy-duty trucks is proposed.Next,the composite material structure is optimized by applying size optimization and stack sequence optimization methods to obtain the higher performance carbon fiber composite front underrun protection beam of commercial vehicles.The results show that the fiber yarn height(H)has the greatest influence on the protective beam,and theH1matching scheme for the front underrun protective beamwith a carbon fiber composite structure exhibits superior performance.The proposed method achieves a weight reduction of 55.21% while still meeting regulatory requirements,which demonstrates its remarkable weight reduction effect.
文摘以非线性数值计算为手段,对比分析缆索系统、加劲梁、桥塔及支承系统等结构系统,研究表明主跨3 500 m CFRP主缆悬索桥具有技术可行性。利用精细有限元结构仿真分析手段,对主跨3 500 m CFRP主缆悬索桥结构体系进行参数敏感性分析,研究结构参数对超大跨径悬索桥静、动力性能影响,结合结构系统数值模型分析研究,确定了主跨3 500 m CFRP主缆悬索桥最优结构体系。建立物理模型,进行CFRP主缆索股的锚固、滑移、弯折等理论分析及静载、疲劳试验研究。研发了可用于实桥的黏结性锚具,锚固效率系数达100%。验证了抗滑移、弯折性能,在鞍座处摩擦系数约0.5,在索夹处达0.331,在鞍座处的弯曲强度超过其抗拉强度的90%,在索夹处几乎不存在弯折问题。以研究成果为依据,进行了主跨3 500 m CFRP主缆悬索桥原型设计。
