关键词： 碳陶复合材料   机械密封   泄漏控制   搅拌设备  

摘要： 文章概述了碳陶复合材料的结构和性能,分析了搅拌设备机械密封工作原理与特殊要求,阐述了搅拌设备机械密封泄漏量的影响因素、测量与评估方法以及控制方法,并进行了碳陶复合材料密封性能实验,以期提高搅拌设备运行安全性和效率。

关键词： 复合材料   剪切性能   GB/T   30970-2014   ASTM   D   7078/D   7078M-05  

摘要： 全面对比分析了单向纤维增强聚合物基复合材料Ⅰ型层间断裂韧性的标准试验方法国标GB/T 30970-2014和美标ASTM D 7078/D 7078M-05的主要异同点,并对相关规定进行了对比分析。结果表明:国标与美标在适用范围、试样尺寸、试验夹具、应变计粘贴、加载速率等方面有一些区别,二者可相互借鉴完善,并结合更多新材料测试的需求不断更新,考虑复杂试验环境和特殊情况,从而制定更适合我国航空航天工业及高端制造业的由V形轨道剪切方法测定复合材料剪切性能的标准试验方法标准。

关键词： 模压工艺   复合材料   纤维显微结构   孔隙演化  

摘要： 模压成型工艺作为树脂基复合材料主要的成型方法,正广泛的应用于航空航天、汽车等领域。如何制造性能优良、缺陷少的复合材料制品尤为重要。本文针对复合材料模压成型中的工艺特点,不仅对模压成型过程中的材料固化和流动行为进行了详细阐述,而且对其性能的影响因素进行深度剖析,包括材料流动诱导的纤维显微结构、材料流动诱导的孔隙演化等因素。通过这些分析结果对采用模压工艺制备复合材料的科研工作者们提供了重要参考。

关键词： 高压逃生艇   吊放   复合材料   碰撞   分层损伤  

摘要： 以饱和潜水用高压逃生艇艇体结构为研究对象,使用显式分析数值法对其碰撞响应进行研究。基于内聚力模型建立了适用于描述分层损伤的渐进损伤模型,基于VUMAT程序开发了适用于正交编织铺层层内损伤的渐进损伤数值模型。建立了多层实体单元艇体外壳层合板结构有限元模型,利用整船有限元模型计算分析了艇体结构的碰撞损伤,并研究了高压氧舱系统质量对碰撞损伤的影响。计算结果表明,分层是艇体碰撞损伤的主要形式;随着碰撞初速度的增加,艇体结构分层面积、与母船之间的碰撞力、艇体碰撞减速时间都会增加,但损伤耗散能占系统总能量的比例会趋于稳定。随着艇内高压氧舱系统质量的增加,艇体结构分层面积和艇体碰撞力都会增加,但是损伤耗散能占系统总能量的比例不断下降。所建立的多层实体单元数值模型可以准确计算层间方向的应力、应变分量,相比传统壳单元和连续壳单元都更加准确。相比于局部结构模型,所使用的全船模型虽然增加了计算时间,但省去了对相邻结构进行数值近似的过程,可以更直观、更完整地展现结构整体响应特征。

关键词： Plastics applications  

摘要： The existing carbon fiber composite drive shaft is usually composed of metal flange and carbon fiber composite shaft tube. The metal flange has heavy weight and needs to be connected to the shaft tube by adhesive bonding or riveting，so it can increase the inertia during starting or braking and affect the overall performance. Therefore，the preparation and torsion test research of all-carbon fiber composite drive shaft with flange and shaft tube integrated molding were presented. The all-carbon fiber composite drive shaft was prepared using the tube coiling and flange flanging and wrapping process，the total length of the drive shaft was 1 980 mm，and the layering scheme was [(±45°)32/45°]. At last，the static torsion and torsional fatigue tests were conducted. According to the test results，the all-carbon fiber composite drive shaft has no damage under 12 000 N·m static torsion test，and its torsional stiffness is 1.93×105 N·m/rad. No damage occurs in the torsional fatigue tests with 200 000 times，which met the normal working requirements. The maximum residual torsional stiffness in the torsional fatigue test is 2.02×105 N·m/rad，and the minimum residual torsional stiffness is 1.89×105 N·m/rad. © 2024 Engineering Plastics Application Magazine. All rights reserved.

关键词： 土木建筑工程  

ISBN: (纸本)9787030775474

摘要： 本书是基于作者近年来对受腐蚀破坏的钢筋混凝土结构的抗震性能评价和改造技术的研究成果而撰写的。首先，考虑应变率、初始静载的影响，建立了预测BFRP板和混凝土在静载下的行为以及BFRP板和混凝土之间的粘结行为的模型。其次，提出了提高槽锚固、钢板、锚栓锚固的混凝土梁构件性能的技术，建立了一个考虑初始裂缝位置、数量和高度的混凝土梁承载能力预测模型，并揭示了BFRP片改造梁的承载能力、刚度和延性等抗震性能的机理。。

关键词： Temperature distribution  

摘要： In order to construct thermoplastic polyurethane (TPU) based flexible circuits using fused deposition modeling (FDM) 3D printing technology. TPU as flexible matrix and industrial grade graphene oxide (GO) as conductive filler were applied to prepare flexible conductive filament used for FDM 3D printing. In order to improve the conductivity of GO，reduced graphene oxide (RGO) was prepared by thermal reduction of GO at high temperature. The RGO/TPU flexible conductive composites were prepared by solvent blending method. The influences of RGO content on the conductivity，mechanical properties，force sensitivity performance，and thermal properties of the RGO/TPU flexible composites were explored. The research results indicate that when the content of RGO is about 12 wt%，the electrical performance of the composite is significantly improved，which is approaching the resistance range of semiconductor materials. RGO can significantly increase the tensile modulus of TPU flexible composite. When the content of RGO reaches 12 wt%，the tensile modulus is about 56.36 MPa，which is nearly 16 times that of pure TPU. But with the increase of RGO content，the elongation at break and breaking strength of the flexible composite decrease significantly. When the strain is 130%，the resistance change rates of filaments with 10 wt% and 12 wt% RGO are only 53.5% and 48.4%，respectively，and the sensitivity coefficients are only 0.41 and 0.38. The addition of RGO can increase the crystallization temperature of the RGO/ TPU flexible composite significantly. However，the RGO with excessive content (≥8 wt%) can lead to a decrease in crystallization temperature. © 2024 Engineering Plastics Application Magazine. All rights reserved.

关键词： Plastics applications  

摘要： Research progress of the thermal conduction mechanisms of polymer composites in recent years was summarized，the theoretical framework models for predicting thermal conductivity were outlined，and highlights that the phonon conduction mechanism was crucial for enhancing the thermal conductivity of thermally conductive polymer composites were introduced. By analyzing the characteristics of Maxwell model，Bruggenman model，Every model，and other comprehensive models，it became evident that these theoretical models provide effective methods for predicting the thermal conductivity of polymer composites. Additionally，the important factors influencing the thermal conductivity of filler-based polymer composites were explored. The influence law of factors such as filler type，filler shape and size distribution，filler content，and interfacial thermal resistance on the thermal conductivity of polymer composites were investigated. Finally，the challenges currently faced in the research of thermally conductive polymer composites were summarized，and future research directions and development trends in this field were discussed. © 2024 Engineering Plastics Application Magazine. All rights reserved.

关键词： Laminated composites  

摘要： At present，according to the composite parameters，the performance data of most standard measurements are more suitable for product inspection and quality control，and the scope of application of standards is often not clearly applicable to the design side，resulting in difficult reference use in Computer Aided Engineering (CAE) analysis and design. In general，in the CAE simulation process of composites，there are still some problems，such as unclear the needed material parameters，unclear test methods，and lack of a complete test system. In view of this，the principles of elastic constitutive parameters and strength parameters of continuous fiber reinforced polymer matrix composites in two forms (laminate and fabric) were introduced，the material parameters required for CAE dynamic and static simulation analysis were defined，and the domestic and foreign test standards for tensile testing，compression testing and shear testing were compared and analyzed，the deficiencies in the design of various test standards were pointed out. Finally，a complete set of material parameter testing method for CAE simulation analysis of continuous fiber reinforced polymer matrix composites was improved and established on the basis of American standard and international standard，so that the measured performance data were more suitable for CAE analysis and design. © 2024 Engineering Plastics Application Magazine. All rights reserved.

关键词： Tensile strength  

摘要： Taking self-made chitin powder (PCH) and chitin micro-nano fiber (MCH) as reinforcing phases for blending and extruding with polylactic acid (PLA)，PCH/PLA and MCH/PLA composites were prepared，respectively. The effects of PCH or MCH on the microstructure and various properties of the composites were studied. The results show that compared with PCH，the interface between MCH and PLA is more closely integrated. When the MCH content is 10 wt% ，the MCH/PLA composite has a maximum tensile strength of 29.25 MPa and a maximum tensile modulus of 1 657.3 MPa，which are 68.5% and 34.6% higher than those of pure PLA，respectively. Its storage modulus at -30 ℃ is 4 406 MPa，which is 16.3% higher than that of pure PLA. When the PCH content is 5 wt% ，the tensile strength of PCH/PLA composite has a maximum tensile strength of 20.27 MPa，which is 16.8% higher than that of pure PLA，while the storage modulus at -30 ℃ is lower than that of pure PLA. Both PCH and MCH can reduce the linear expansion coefficient and water contact angle of PLA，and improve PLA water absorption. When the MCH content is 10 wt%，the linear expansion coefficient of MCH/PLA composite is reduced by 35.8% compared to pure PLA，effectively improving the dimensional stability of the composite. The above results indicate that MCH/PLA composite with 10 wt% MCH has the potential to replace petroleum-based plastics in biodegradable packaging and other fields. © 2024 Engineering Plastics Application Magazine. All rights reserved.