Design and Mechanical Properties of a New Clamp-Type Carbon Fiber Materials Tension Anchoring System

Carbon fiber materials are widely used in bridge reinforcement techniques, while conventional carbon fiber material tensile anchoring equipment produces a large prestressed loss. This paper analyzes the deficiencies of existing tensile anchoring systems at home and abroad, summarizing the cause of prestressed losses, and combining with existing anchoring systems, a new type of clamp type carbon fiber cloth tension anchoring system is proposed. The amount of deformation of the anchoring system is reduced by about 20%, which in turn reduces the system prestress loss caused by the system deformation. The ABAQUS finite element analysis software is used to numerically simulate the thickness of the tension anchor system and the force of the fixture at different inclination angles. Compare the experimental measurement data, under consideration of the mechanical properties of the system, making errors, and installation convenient prerequisites, the mechanical properties of the system are optimal when the thickness of the fixed plate is 30mm and the clamp tilt angle is 5 °.

Rancang Bangun Body Fibercarbon dan Simulasi Aerodinamis dengan Ansys untuk Mobil Hemat Energi Kategori Prototype

<p><em>Body is one of mandatory components for the main vehicle, which is a car because the face of the car is located on the body. Moreover, the car used for the body competition must not only be good visually but also have to look at its aerodynamics. In this study, discussing the aerodynamics of a prototype energy-efficient car body with carbon fiber material before it is produced and applied it must first be simulated aerodynamically on an aerodynamic simulation software. The vehicle to be simulated uses a 1:1 scale assuming the actual conditions. From the simulations carried out by the three body type models, the results are Model 1 with maximum Velocity of 64.0925 m/s and a maximum pressure of 1663.09 Pa and a Drag coefficient of: 309.85976, Lift coefficient of: 125.52961, Drag force of : 189.7891 N and Lift force of: 76.886889 N. Model 2 with a maximum Velocity of 58.14 m/s and a maximum pressure of 1350.55 Pa, Drag coefficient of : 399.09712, Lift coefficient of: 455.23564 , Drag force of : 244.44699N and Lift force of: 278.83183 N. Model 3 with a maximum Velocity of 59.8387 m/s and a maximum pressure of 1136.72 Pa, Drag coefficient of : 610,89875, Lift coefficient of: 764,99562, Drag force of: 374,17548 N and Lift force of: 468,55982 N. Based on results analysis using ansys software, Model 1 was chosen because it has the smallest Drag Coefficient, Lift Coefficient, Drag Force and Lift Force.</em></p>

WAYS TO INCREASE THE LIGHTNING PROTECTION OF CARBON FIBER PLASTICS

Based on the previously conducted analytical study of the destruction of conducting composites by lightning currents, methods for increasing their lightning resistance are considered. To substantiate these methods, an analysis of the current distribution at different ratios of transverse and longitudinal resistivity was carried out. One of the methods using conductive additives in the composition of the binder material allows you to influence the anisotropy of the conductive medium of carbon fiber. The parameters of the range of the degree of anisotropy of carbon fiber are proposed to achieve uniform current spreading and reduce the radius of destruction of the composite by lightning currents. The formula for the fracture radius in the absence of anisotropy is obtained and estimated calculations are performed. The method of reinforcing carbon fiber with thin wires to increase its lightning resistance is considered. Calculated expressions are found for estimating the weight, the number of delays per unit area, and the absence of overheating. Comparisons of weight characteristics for various reinforcing materials are carried out and a conclusion is made on their effectiveness. The advantages and disadvantages of this method of protection are considered. The third way to increase the lightning resistance of the composite suggests using a carbon fiber material with a woven structure as a protective coating. This protection reduces the energy release in the material and the size of the damage. It is concluded that it is necessary to control the lightning protection parameters and choose a coating with the required characteristics. The principles and criteria of lightning protection for real carbon fiber plastics will be considered in subsequent works.

STABILIZATION OF TUFF MATERIAL BY ELECTROSPINNING OF LOW AREAL WEIGHT TPU VEIL MATERIAL

The Tailored Universal Feedstock for Forming (TuFF) material is an aligned, discontinuous carbon fiber material with high fiber volume fraction up to 63% and mechanical performance equivalent to continuous fiber, unidirectional composites. The short fiber material allows at least 40% in-plane extension during processing enabling metal-like forming approaches simplifying composites manufacturing significantly. Traditionally, TuFF preforms are produced at areal weight (AW) of ~8 grams per square meter (gsm), stacked and impregnated with thermoset or thermoplastic polymer to create prepreg followed by curing/consolidation in an autoclave or stamp forming process resulting in high-performance structural parts. Here, the impregnated TuFF prepreg can be handled the same way as traditional continuous fiber prepreg. In contrast, to enable liquid composite molding (LCM) processes with TuFF material, the unimpregnated (dry) short fiber TuFF preforms must be stabilized for handling and preforming purposes. This paper details an electrospun veil approach as shown in Figure 1 to stabilize the individual TuFF sheets while maintaining the in-plane extensibility for complex geometry parts. Electrospun TPU fibers are applied onto the TuFF surface and then consolidated via a combination of heating and pressure, formingtrials were carried out using the stabilized preforms and composites werefabricated using LCM. Tensile tests show ~90-95% property retention versus theunstabilized baseline. The approach allows fabrication of stabilized TuFF fabricsfor the first time enabling the use of LCM processes for complex geometry parts.

Influence of Heavy Weight Drill Pipe Material and Drill Bit Manufacturing Errors on Stress State of Steel Blades

Drilling volumes should be increased in order to increase hydrocarbon production, but this is impossible without the usage of high-quality drilling tools made of modern structural materials. The study has to analyze the design, technological and operational methods to increase the performance of drilling tools made of various materials and has highlighted prospects of technological method applications. The scientific novelty of the study consists in the development of a new analytical model of PDC drill bit–well interaction. The developed model takes into account the drill bit manufacturing errors in the form of bit body–nipple axes misalignment on the drill bit strength. This result makes it possible to determine the permissible manufacturing errors to provide safe operation of the drill bit. It is established that there is an additional transverse force that presses the drill bit to the well wall in the rock due to manufacturing errors. It is determined that the magnitude of this clamping force can be significant. The material effect has been analyzed on additional clamping force. It is established that geometric imperfection of the drill bit causes the minimal effect for the elastic system of the pipe string, which includes a calibrator and is composed of drill pipes based on composite carbon fiber material, and the maximal effect—for steel drill pipes. Polycrystalline diamond compact (PDC) drill bit and well wall contact interaction during operation in non-standard mode is considered. Non-standard stresses are determined, and the strength of the blades is estimated for different values of drilling bit manufacturing error.

Preparation of Fe-Cu-Based Friction Material and its Adoption in Automobile Mechanical Mechanism

To prepare a kind of Fe-Cu-based friction material with good friction performance and wear resistance, and apply it to the brake structure of automobile machinery, the powder metallurgy method is used to prepare the friction materials in the standard with 4% Ni, 4% Mo and 2% Sn as the auxiliary material, SiC, Al2O3, and zircon sand as the basic friction material, 8% graphite and 3% MoS2 as the lubricating component. Meanwhile, 50% Fe and 20% Cu is used for the preparation of friction materials. The friction and wear resistance can be increased by increasing the carbon fiber content of 0-8% concentration of the material. The results show that the friction coefficient of the Fe-Cu-based friction material is relatively gentle after the addition of 2% carbon fiber, and the compactness peaks, reaching 93.3%. Its shear strength and impact strength peak, which are 37.42Mpa and 6.7J/cm2 respectively. 4% carbon fiber material with a hardness of 120.2 HV is the hardest one, followed by 2% carbon fiber material with a hardness of 118.1 HV. Added with 2% carbon fiber, the abrasion amount of the friction-based material is 0.0027 g at room temperature and-0.0008 g at 400°C after 60 minutes respectively. With all indicators considered, the result shows that the friction performance and wear resistance of Fe-Cu-based friction materials can be increased by adding 2% carbon fiber during the preparation of basic friction materials.