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Stiffness design and mechanical performance analysis of transverse leaf spring suspension
Bao Zhang,Hongnan Wang,Zhi Li,Tangyun Zhang 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.3
Suspension stiffness affects vehicle comfort and handling performance. The stiffness optimization of the transverse leaf spring suspension can be achieved by adjusting the distance between the two central installation positions of the leaf spring. This method can avoid changing the structure of the leaf spring, reduce the difficulty of product development, and shorten the product development cycle, so this type of suspension has high engineering application value. In the paper, a finite element model of the transverse leaf spring is established, and the characteristics of the stiffness, deformation and stress of the leaf spring with the distance are studied. According to the objectives of suspension dynamic deflection, body roll angle and leaf spring reliability, the distance matching design is carried out, and the design scheme is experimentally verified. The research shows that the stiffness of the leaf spring under the opposite direction loading condition is greater than that of the same direction loading condition, and the difference between the two data increases with the increase of the distance. When the distance is 800 mm, the stiffness of the suspension is 102.1 N/mm under the same loading and 220.4 N/mm under reverse loading, the maximum stress is 1487 MPa, the dynamic deflection 39.2 mm, and the maximum body roll angle is less than 6.0°. All of the above indicators meet the design requirements. The research results provide theoretical basis and reference for the design of a transverse leaf spring suspension.
Jiatai Gu,Zhenzhen Quan,Liming Wang,Hongnan Zhang,Ni Wang,Xiaohong Qin,Rongwu Wang,Jianyong Yu 한국섬유공학회 2022 Fibers and polymers Vol.23 No.6
Membranes with the functions of waterproofness and breathability are of great interest due to their huge scientificand commercial value in many practical applications. However, designing such membranes with a desirable performance bysimple and efficient fabrication process remains a tremendous challenge. Herein, novel binary structured composite fibrousmembranes were developed for waterproof and breathable applications via simple one-step multi-jet electrospinningtechnology. This composite membranes were made up of polyvinylidene fluoride (PVDF) and polyacrylonitrile (PAN). PVDF was incorporated into the PAN fiber matrix as a modifier to improve the hydrophobic behavior of fibers. Meanwhile,PVDF microspheres/fibers were employed as building blocks to orderly embed in PAN/PVDF fiber framework, impartingthe composite membranes with fluffy micro-nano hierarchical structures. Consequently, with the integrated features of robusthydrophobicity as well as elaborate fiber-microsphere binary structure, the resultant composite membranes exhibitedsynergistically modest waterproof and breathable performances with the hydrostatic pressure of 18.04 kPa, water vaportransmittance (WVT) rate of 4.65 kg m-2 d-1, and air permeability of 64.19 mm s-1. This simple preparation process andunique composite structure may provide a new insight to design and fabricate waterproof and breathable membranes forvariously potential applications, including the protective clothing, separation membrane, and filter.
Zhao, Wei,Chen, Xin,Yan, Changjiang,Liu, Hongnan,Zhang, Zhihong,Wang, Pengzu,Su, Jie,Li, Yao Asian Australasian Association of Animal Productio 2012 Animal Bioscience Vol.25 No.1
The trial was conducted to evaluate the effects of sea buckthorn leaves (SBL) on meat flavor in broilers during heat stress. A total 360 one-day-old Arbor Acre (AA) broilers (male) were randomly allotted to 4 treatments with 6 replicates pens pretreatment and 15 birds per pen. The control group was fed a basal diet, the experimental group I, II and III were fed the basal diet supplemented with 0.25%, 0.5%, 1% SBL, respectively. During the 4th week, broilers were exposed to heat stress conditions ($36{\pm}2^{\circ}C$), after which, muscle and liver samples were collected. High performance liquid chromatography (HPLC) was performed to measure the content of inosine monophosphate (IMP); Real-Time PCR was performed to determine the expression of the ADSL gene. The results showed that the content of breast muscle IMP of group I, II and III was significantly increased 68%, 102% and 103% (p<0.01) compared with the control, respectively; the content of thigh muscle IMP of group II and III was significantly increased 56% and 58% (p<0.01), respectively. Additionally, ADSL mRNA expression in group I, II and III was increased significantly 80%, 65% and 49% (p<0.01) compared with the control, respectively. The content of IMP and expression of ADSL mRNA were increased by basal diet supplemented with SBL, therefore, the decrease of meat flavor caused by heat stress was relieved.