Study of technological defects arising during automated laying of prepregs (review)

2021 ◽  
Vol 87 (11) ◽  
pp. 33-38
Author(s):  
P. N. Timoshkov ◽  
M. N. Usacheva ◽  
V. A. Goncharov ◽  
A. V. Khrulkov
Keyword(s):  
Composite Materials ◽  
Defect Formation ◽  
Physical And Mechanical Properties ◽  
Technological Parameters ◽  
Fiber Placement ◽  
Negative Effect ◽  
Tension And Compression ◽  
Automated Fiber Placement ◽  
Technological Defects

Technologies of automated laying out of fibers (Automated Fiber Placement — AFP) and tapes (Automated Tape Laying — ATL) are used in the manufacture of blanks from polymer composite materials (PCM) for subsequent autoclave or other type of molding. The frequency of defect formation upon laying depends on the complexity of the certain part and the technological parameters (the tape width, speed of laying and idle time, temperature, deviations from the calculated trajectory, etc.). We present a review of the main defects thus formed along with the analysis of the reasons for their appearance and their effect on the physical and mechanical properties of composite materials. It is shown that the defects change the thickness and reduce the strength of the PCM under tension and compression. Moreover, the inaccuracy of fiber placement when using the AFP technology has a negative effect on the quality of the materials. The results presented can be used in the further study of the effect of defects on the PCM properties and reasons for defect formation, as well as in developing promising universal computational program that can provide reduction of the number of corresponding experimental tests.

scholarly journals METHOD OF SAMPLE MANUFACTURING FROM MULTILAYER COMPOSITE MATERIALS FOR STUDYING THEIR MECHANICAL PROPERTIES

2018 ◽  
pp. 16-23
Author(s):  
Alsaid Mazen ◽  
Ali Salamekh
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Polymer Composite ◽  
Testing Machine ◽  
Physical And Mechanical Properties ◽  
Polymer Composite Materials ◽  
Technological Parameters ◽  
Cutting Out ◽  
Method Of Production ◽  
Economic Considerations

In the last decades there is increasing the need to apply polymer composite materials in different industries, particularly in shipbuilding. There are developing single structures made from polymer composite materials to be used on board ships. The article focuses on technology of manufacturing slabs from polymer composite materials to carry out mechanical testing in the laboratory special standard units. Mechanical properties of polymer composite materials depend on molding technologies. There has been described a technology of sample manufacturing from polymer composite materials reinforced with glass fiber mat with fiberglass plastics. The technique of testing the specified samples for tensile strength has been considered. The sizes and shapes of the samples as well as the technological parameters of the manufacturing process have been validated, depending on the standard requirements and the technological features of the testing machine. The physical and mechanical properties of the components that make up the composite materials are considered. The sequence of stacking layers for preparation of plates from composite materials is indicated. The dimensions of the plates for cutting out finished samples are determined, depending on the method of production. The way of laying plates from composite materials has been chosen on the base of economic considerations and conditions of accessibility. The obtained results of mechanical properties can be used in solving problems of application of polymer composite materials in shipbuilding, for example, in manufacturing superstructures of some dry cargo vessels.

Impact of layup rate on the quality of fiber steering/cut-restart in automated fiber placement processes

2015 ◽  
Vol 22 (2) ◽  
pp. 165-173 ◽  
Author(s):  
Jihua Chen ◽  
Teresa Chen-Keat ◽  
Mehdi Hojjati ◽  
AJ Vallee ◽  
Marc-Andre Octeau ◽  
...  
Keyword(s):  
Compaction Pressure ◽  
Experimental Studies ◽  
Process Condition ◽  
Processing Parameters ◽  
Experimental Results ◽  
High Quality ◽  
Fiber Placement ◽  
Automated Fiber Placement

AbstractDeveloping reliable processes is one of the key elements in producing high-quality composite components using an automated fiber placement (AFP) process. In this study, both simulation and experimental studies were carried out to investigate fiber steering and cut/restart under different processing parameters, such as layup rate and compaction pressure, during the AFP process. First, fiber paths were designed using curved fiber axes with different radii. Fiber placement trials were then conducted to investigate the quality of the steered fiber paths. Furthermore, a series of sinusoidal fiber paths were fiber placed and investigated. Moreover, a six-ply laminate with cut-outs in it was manufactured in the cut/restart trials. The accuracy of the fiber cut/restart was compared at different layup rates for both one- and bi-directional layups. Experimental results show that it was possible to layup steered fiber paths with small radii of curvature (minimum 114 mm) designed for this study when the proper process condition was used. It was observed from the cut/restart trials that the quality of tow cut was independent of layup speed; however, the accuracy of tow restart was related to the layup speed. The faster the layup speed, the less accurate was the tow restart.

scholarly journals THE DEVELOPMENT OF AUTOMATED LAYING: FROM THE BEGINNING TO OUR DAYS (review) Part 2. Automated Fiber Placement (AFP)

2021 ◽  
pp. 117-127
Author(s):  
P.N. Timoshkov ◽  
◽  
V.A. Goncharov ◽  
M.N. Usacheva ◽  
A.V. Khrulkov ◽  
...  
Keyword(s):  
Composite Materials ◽  
Complex Geometry ◽  
Modern Equipment ◽  
Fiber Placement ◽  
Automated Fiber Placement

Automated Fiber Placement is one of the main technologies used today for manufacturing of modern composite materials from narrow bundles of 3.2; 6.35 and 12.7 mm wide, which are usually stacked in one sequence using a special head. AFP allows you to lay out parts with complex geometry. The second part considers the development of technology from its origination to the present day and provides the description of the laying process and modern equipment on the market.

In Situ Thermal Nondestructive Evaluation for Assessing Part Quality During Composite Automated Fiber Placement

2018 ◽  
Vol 1 (4) ◽  
Author(s):  
Elizabeth Gregory ◽  
Peter Juarez
Keyword(s):  
Nondestructive Evaluation ◽  
Composite Fiber ◽  
Cylindrical Part ◽  
Defect Characterization ◽  
Data Sets ◽  
Fiber Placement ◽  
Part Quality ◽  
Automated Fiber Placement

This paper presents data from an innovative nondestructive evaluation (NDE) method for automated composite fiber placement fabrication. Using Infrared images of the fiber, as it was being placed, we are able to provide valuable information about the quality of the part during fabrication. Herein, we discuss the methodology for data collection and processing. The described in situ thermal NDE process is found to be applicable for identifying fiber tow overlaps, gaps, twists, puckering, and poor ply adhesion prior to cure, thereby reducing the time and cost associated with post cure flaw repair or scrapping parts. This paper also describes the process of assembling data sets for an entire part beyond simple frame by frame analysis. Example data sets for both a flat part and a larger cylindrical part are presented to demonstrate the type of defect characterization information that can be obtained.

scholarly journals Effect of compaction roller on layup quality and defects formation in automated fiber placement

2019 ◽  
Vol 39 (1-2) ◽  
pp. 3-20 ◽  
Author(s):  
Nima Bakhshi ◽  
Mehdi Hojjati
Keyword(s):  
Experimental Study ◽  
Finite Element ◽  
Pressure Distribution ◽  
Finite Element Simulations ◽  
Process Conditions ◽  
Fiber Placement ◽  
Static Testing ◽  
Contact Width ◽  
Automated Fiber Placement

Application of automated fiber placement is limited by defects formed in the prepreg tows during the layup process. An extensive experimental study is performed to investigate the effect of compaction roller on the quality of the layup. Five different compaction rollers with different stiffness and architectures were manufactured and employed to dispense prepreg tows at various process conditions. Layup quality was examined and different defects including tow buckling and blister were identified. In addition to automated fiber placement trials, static testing and finite element simulations were performed to probe the pressure distribution and contact width of each roller. This data was used to support and understand the results of the automated fiber placement trials. Results indicate the solid elastomer rollers that are compliant enough to produce the same level of contact width under similar levels of compaction forces are superior to the perforated rollers in terms of achievable layup quality.

ROBOTIC LAYING OUT OF PREPREGS AS AN ALTERNATIVE TO TECHNOLOGY TO ATL AND AFP (review)

2021 ◽  
pp. 87-98
Author(s):  
P.N. Timoshkov ◽  
◽  
V.A. Goncharov ◽  
L.N. Grigoreva ◽  
M.N. Usacheva ◽  
...  
Keyword(s):  
Composite Materials ◽  
Cost Effective ◽  
Manual Labor ◽  
Automated Production ◽  
Fiber Placement ◽  
Automated Fiber Placement ◽  
Complex Parts

With the growing use of composite materials, the automated production of parts using prepreg is gaining increasing interest. There are two main types of prepreg laying automation: Automated Tape Laying (ATL) and Automated Fiber placement (AFP). Both of these technologies are not always cost effective for all types of parts, and manual labor tends to be used to make complex parts with low production volumes. As an alternative to these two dominant automation solutions, there are 4 options for automated laying with manipulators.

scholarly journals THE DESTRUCTIVE EFFORT OF THE CUTTING IN THE INTERACTION BETWEEN THE BLADES OF DISC KNIFE AND HERBAL MASS

2020 ◽  
pp. 29-36
Author(s):  
Oleksandr Kholodyuk
Keyword(s):  
Cutting Force ◽  
Physical And Mechanical Properties ◽  
Scientific Work ◽  
Technological Parameters ◽  
Sliding Angle ◽  
General Process ◽  
Energy Consuming ◽  
Grinding Machine ◽  
Power And Energy

The process of cutting is widely used during the stockpiling and preparation of fodder - the processing of stems by the direct application of the force that arises at the cutting edge of the knife. Almost 85% of stem fodder are ground fodder for the stockpiling of which the forage harvesters are used. Grinding of leaf mass is one of the most energy-consuming operations in the general process of stockpiling and the final quality of the fodder depends on it. The energy intensity of the grinding process is influenced by both the constructive and operating parameters of the machine, the cutting pair, and the physical and mechanical properties of the leaf-stem mass. Therefore, the development of grinding machines, the biter-knife in particular, should be carried out on the basis of detailed studies of the process of cutting grass mass, taking into account the current power and energy parameters. The object of the study in this article was the process of cutting a herbal mass with a biter-knife grinding machine containing an active disk knives. The purpose of the work was to establish the analytical dependence of the destructive cutting force in the interaction of the blade of the disk knive of biter-knife grinding machine with herbal mass. The task of the work was: to analyze the researches and publications on establishing the effort of cutting a layer of leaf stem and influence of various factors on its magnitude; to establish a mathematical model of calculation the critical effort of cutting a layer of grass mass with a cutting pair: double finger of the feed rotor - a disk knife during the cutting with sliding. The research methodology was based on the analysis of the interaction of the working parts of the grinding machine with herbal mass using the methods of theoretical mechanics. In the scientific work the interaction of single-blade blade of a disk knife of a biter-knife grinding machine with a leaf-stem mass is considered under the condition of double-backed cutting with sliding. The force interaction of the knife`s blade with the grass mass was analyzed and the dependence (3) of the calculation of the critical destructive cutting force Rkr was determined. From the obtained expression it is established that its magnitude is influenced by both the constructive parameters of the cutting steam and the technological parameters of the grinding machine. Also the magnitude of the destructive force is affected by the transformed angle of sharpening of the blade of the disk knife and the sliding angle.

scholarly journals ДОСЛІДЖЕННЯ ПРОЦЕСУ ДУБЛЮВАННЯ ДЕТАЛЕЙ ОДЯГУ ІЗ ШТУЧНОГО ХУТРА

2021 ◽  
Vol 146 (3) ◽  
pp. 129-138
Author(s):  
А. П. Бусько ◽  
А. Т. Арабулі
Keyword(s):  
Mechanical Properties ◽  
Experimental Investigation ◽  
Mathematical Models ◽  
Materials Science ◽  
Physical And Mechanical Properties ◽  
Raw Material ◽  
Design Stage ◽  
Technological Parameters ◽  
Systematic Analysis

Analysis of the features of the structure of faux fur of different raw materials to improve the shape stability of products and increase the exploitation process. Determination of technological parameters of the process of duplication of garments made of faux fur at which a standardized level of quality of the duplication operation is duplicated.Performing experimental investigation to determine the physical and mechanical properties of artificial fur. The work used the well-known methods for determining the flexural stiffness, air permeability and hydrophobicity of artificial fur were used in the work. Theoretical and experimental investigation is based on the basic principles of textile materials science. Systematic analysis and generalization were used to determine the state of the question and set the task. The experiment of the process of duplication of faux fur parts was planned and two-factor mathematical models were obtained, which are adequate to the researched process. The influence of the duplication process on artificial fur of different raw material composition is analyzed. The values of indicators of physical and mechanical properties of modern faux fur are determined. On the basis of two-factor mathematical models, recommendations are given on the choice of technological parameters of duplication of garments made of faux fur. The regularities of the process of duplicated of garment parts made of faux fur with adhesive gasket material under static loading are established. The values of indicators of physical and mechanical properties of modern faux fur are determined. The obtained scientific results allow at the design stage to rationally select faux fur in the manufacture of outerwear, and certain rational technological parameters of the process of duplication of garments from faux fur allow to ensure a standardized level of quality of duplication operation while minimizing energy losses of equipment.

Effect of autoclave process on the quality of thermoplastic composite truncated cones manufactured using automated fiber placement technique

2015 ◽  
Vol 22 (2) ◽  
pp. 175-186
Author(s):  
Farjad Shadmehri ◽  
Xiao Cai ◽  
Mehdi Hojjati ◽  
Jihua Chen ◽  
Suong V. Hoa
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Natural Frequencies ◽  
Thermoplastic Composite ◽  
Fiber Placement ◽  
Autoclave Process ◽  
Stiffness Properties ◽  
Automated Fiber Placement ◽  
Placement Technique

AbstractIn order to investigate the effect of autoclave process on the stiffness properties of thermoplastic composite truncated cones made by automated fiber placement technique (AFP), two short truncated cones were made out of advanced thermoplastic composite material (carbon fiber/PEEK). Then, the truncated cones were tested by impulse excitation of vibration to get experimental natural frequencies. Tensile and compression test coupons were made out of the same material using hand layup and autoclave process, and stiffness properties were characterized experimentally. Furthermore, finite element analysis was performed to extract theoretical natural frequencies using material properties obtained from coupon testing. Comparison between the natural frequencies obtained using the finite element method and experimental modal analysis was conducted. Furthermore, the two truncated cones were treated inside the autoclave, and changes in the thickness and density were measured. After autoclave treatment, experimental modal analysis was repeated to investigate the possible changes in natural frequencies. The finite element model was also updated upon the changes in thickness and density of the truncated cones, and consequently, comparison between the theoretical and experimental natural frequencies was carried out again. Also, micrographs of two truncated cones were taken before and after autoclave treatment to examine the autoclave effect on the quality of the samples.

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