On the Mechanical Analysis and Control for the Tension System of the Cylindrical Filament Winding

The constant winding tension can make the filament arranged in order. The stress distribution between the filament balance fully gives play to the enhancement of filament, and increases the intensive workload of the composite winding material. This paper conducts the mechanical analysis for the unwinding roller and tension measuring roller of the cylindrical winding machine so that gets the mechanical model, gives error compensation formula caused by the radius change of the yarn group in the unwinding side, designs the closed-loop control system and utilizes the dynamical- integral PID control strategy to achieve the tension control during the process of the cylindrical winding.

Strain-Rate Dependency of a Unidirectional Filament Wound Composite under Compression

This article presents the results of experimental studies concerning the dynamic deformation and failure of a unidirectional carbon fiber reinforced plastic(T700/LY113)under compression.The test samples were manufactured through the filament winding of flat plates.To establish the strain rate dependencies of the strength and elastic modulus of the material,dynamic tests were carried out using a drop tower,the Split Hopkinson Pressure Bar method,and standard static tests.The samples were loaded both along and perpendicular to the direction of the reinforcing fiber.The applicability of the obtained samples for static and dynamic tests was confirmed through finite elementmodeling and the high-speed imaging of the deformation and failure of samples during testing.As a result of the conducted experimental studies,static and dynamic stress-strain curves,time dependencies of deformation and the stress and strain rates of the samples during compression were obtained.Based on these results,the strain rate dependencies of the strength and elasticity modulus in the strain rate range of 0.001-6001/s are constructed.It is shown that the strain rate significantly affects the strength and deformation characteristics of the unidirectional carbon fiber composites under compression.An increase in the strain rate by 5 orders of magnitude increased the strength and elastic modulus along the fiber direction by 42%and 50%,respectively.Perpendicular loading resulted in a strength and elastic modulus increase by 58%and 50%,respectively.The average strength along the fibers at the largest studied strain rate was about 1000MPa.The obtained results can be used to design structural elements made of polymer composite materials operating under dynamic shock loads,as well as to build models of mechanical behavior and failure criteria of such materials,taking into account the strain rate effects.

Analysis for the residual prestress of composite barrel for railgun with tension winding

Based on the elastic theory of cylindrical shells and the theory of composite laminates,a prediction model for the residual prestress of the simplified round composite barrel for railgun is established.Only the fibre pretension is considered in this model.A three dimensional numerical simulation for the residual prestress in the railgun barrel is carried out,by combining the temperature differential method with the element birth and death technology.The results obtained by the two methods are compared.It reveals that the distribution trends of residual prestress are consistent.And the difference for residual prestress in the filament wound composite housing of barrel is relatively small.The same finite element method is used to analysis the residual prestress in the non-simplified composite barrels for railgun,which are under different control modes of winding tension.The results mean that the residual prestress in barrel will increase while the taper coefficient for winding is decreasing.Therefore,the sealing performance in bore is improved,but the strength of the filament wound composite housing drops.In addition,the axial and circumferential residual prestress in the filament wound composite housing with constant torque winding are close to the ones in iso-stress design for barrel.

GFRP Poles for Traffic Signs and Signal Poles: A Case Study in Saudi Arabia

GFRP poles have been widely used as lighting poles but their use as traffic signs and signal poles is still under development. This paper highlights the literature review and case study of using GFRP poles for traffic signs and signal poles in the Eastern Province of Saudi Arabia. The case study details the design of poles, construction, maintenance and their performance. Traffic sign poles were manufactured using filament winding and signal poles using pultrusion process. AASHTO Standard “Specifications for Structural Supports for Highway Signs, Luminaires and Traffic Signals” and ANSI 136.2. were used as materials specification and design for the pole. There is a need to develop dedicated design and construction guidelines to standardize the construction process. Further study about the crash resistance of GFRP poles at different speeds needs to be explored. In addition, the paper presents a high level comparison between the different materials like weight, safety, environmental degradation, strength, service life, durability in an aggressive environment, carbon footprint and economics.

Structural optimization of filament wound composite pipes

An optimization procedure is developed for obtaining optimal structural design of filament wound composite pipes with minimum cost utilized in pressurized water and waste-water pipelines.First,the short-term and long-term design constraints dictated by international standards are identified.Then,proper computational tools are developed for predicting the structural properties of the composite pipes based on the design architecture of layers.The developed computational tools are validated by relying on experimental analysis.Then,an integrated design-optimization process is developed to minimize the price as the main objective,taking into account design requirements and manufacturing limitations as the constraints and treating lay-up sequence,fiber volume fraction,winding angle,and the number of total layers as design variables.The developed method is implemented in various case studies,and the results are presented and discussed.

Multi-objective optimization of different dome reinforcement methods for composite cases

A multi-objective optimization method was proposed for different dome reinforcement methods of a filament-wound solid rocket motor composite case based on a Radial Basis Function(RBF)model.Progressive damage of the composite case was considered in a simulation based on Hashin failure criteria,and simulation results were validated by hydraulic burst tests to precisely predict the failure mode,failure position,and burst pressure.An RBF surrogate model was estab-lished and evaluated by Relative Average Absolute Error(RAAE),Relative Maximum Absolute Error(RMAE),Root Mean Squared Error(RMSE),and R^(2)methods to improve the optimization efficient of dome reinforcement.In addition,the Non-dominated Sorting Genetic Algorithm(NSGA-II)was employed to establish multi-objective optimization models of variable-angle and variable-polar-radius dome reinforcements to investigate the coupling effect of the reinforcement angle,reinforcement layers,and reinforcement range on the case performance.Optimal reinforce-ment parameters were obtained and used to establish a progressive damage model of the composite case with dome reinforcement.In accordance with progressive damage analysis,the burst pressure and performance factor were obtained.Results illustrated that variable-angle dome reinforcement was the optimal reinforcement method compared with variable-polar-radius dome reinforcement as it could not only ensure the reinforcement angle’s continuous changing but also decrease the mass of composite materials.Compared with the unreinforced case,the reinforced case exhibited an increase in the burst pressure and performance factor of 36.1%and 23.5%,respectively.