Modeling of Mechanical Properties of the Polymeric Composite Reinforced with Braided Preform

Braided composite structures based on preforms are widely used in various industries. Owing to use of such preforms high speed and efficiency of the process of manufacturing of polymeric composite materials and structures on their basis can be provided. Knowledge of their properties in the design allows optimizing the production of structures with the specified parameters. The paper gives the review of three approaches to the description of physical and mechanical characteristics of the composite with braided fixtures – based on the classical theory of layered media, rod-based model, and the method of polynomial approximation. The necessary estimated dependencies were derived in order to predict the elastic and structural behavior of the composites under study at any reinforcement angle according to the known characteristics of predetermined angles. Synthesized design parameters, as distinct from the existing ones, allow predicting strength characteristics of the composite based on the braided hoses depending on the positioning and location of the material on the shape-generating surface. For the verification of theoretical results, a number of experimental studies have been carried out with the formation of samples of the material with the different reinforcing angles. Comparison of the analytical and experimental results allows drawing the conclusions that rod-based model gives the best results for the description of elastic behavior of the polymeric composite materials, whereas the obtained polynomial dependences are recommended for the structural behavior. The results of the work represent the basis for solving the problems of calculation of strength of the structures made of composite materials based on the braided preforms

Thermal aging effect on the failure loads of adhesively strap joints

In this study, the effects of thermal aging on failure loads in adhesively strap joints were investigated. Thermal aging treatment was applied to the woven glass fibre/epoxy composite plates with eight-layered 0° fibre reinforcement angle, epoxy-based adhesive and to the adhesively strap joints produced with these materials. The strength of the adhesively strap joints of single strap and double strap was determined by static tensile tests. Three conditions were analyzed in the thermal aging process. The first group samples were thermally aged at a temperature of 75, 100 and 150℃ with a constant time of 4 h. The second group samples were thermally aged at a constant temperature of 150℃ for 2, 4, 6 and 8 h and the third group samples were kept at room temperature (not aged). The failure loads of samples which are exposed to thermal aging were compared with the failure loads of the non-aged samples. As a result of experimental studies, it has been determined that the failure loads of thermally aged samples have increased by 27.7% to 133.1%.

Analysis of Initial Stress Anchor Wire Anchoring Mechanism and its Parameter Optimization

Initial stress anchor wire anchoring technology has the merits of fast speed, small perturbation and economic when healing unstable rock side slope. Choosing the spacing, position, angle of reinforcement anchor wire plays a vital role in reinforcement stability and economy. The landslide of an open pit was elected as project background in this paper. Operation model was set up by Lagrange arithmetic which analyzed the reinforcement mechanic and broken pattern of anchor wire. And it defined that the optima spacing is 8m. The anchor wire reinforcement angle and institution position research were researched by using limit balance theory. The optimum design angle obtained is -20°~20°, and the optimum institution position is in the range of 1/5~1/2 of the lower reinforcement side slope height.

Basic Principles of Hose Design

Fundamentals of hose design have not changed with the introduction of new and improved component materials. Hose consists of three basic elements which are tube, reinforcement, and outer cover—with each serving a primary function. The tube or inner liner contains and resists the fluid conveyed and transmits forces created by the internal pressures to the strength member. The reinforcement or strength member contains the forces created by the fluid pressure. The outer cover protects hose reinforcement and resists external environment and damage. This paper is primarily concerned with the design concepts of the strength member or reinforcement as a functional component to resist and control forces created in service. Design principles relating to reinforcement angle, burst strength, and length change under pressure are presented for various hose styles. Braided, spiral, wrapped, loomed, wrapped ply and knitted hose styles are reviewed and compared. Reinforcement materials, their types, relative strengths and advantages are summarized. Examples of specific applications of hose are presented to illustrate hose design principles in action in industry.