Conical Thermoplastic Composite Anisogrid Lattice Structure by Innovative Out-of-Autoclave Molding Process

2021 ◽  
Author(s):  
Fabrizio Quadrini ◽  
Daniele Santoro ◽  
Leandro Iorio ◽  
Loredana Santo
Keyword(s):  
Mechanical Performance ◽  
Lattice Structure ◽  
Glass Fibers ◽  
Density Measurement ◽  
Thermoplastic Composite ◽  
Molding Process ◽  
Conical Structure ◽  
Out Of Autoclave ◽  
Composite Lattice

Abstract A new manufacturing process for thermoplastic (TP) composite parts has been used to produce conical anisogrid composite lattice structure (ACLS). An out-of-autoclave (OOA) process has been prototyped by using the compaction exerted by a heat-shrink tube after its exposition to heat in oven. Narrow thermoplastic prepreg tapes have been wounded on a metallic conical patterned mold at room temperature; then, the conical structure has been inserted in the heat-shrink tube and heated. TP unidirectional prepreg tapes have been used with polypropylene matrix and glass fibers. After molding, the TP ACLS has been tested under axial and transverse compression. Conical adapters were used in the transverse loading condition to allow uniform application of the load. Density measurement has been also performed to assess the quality of the OOA process. Results of this study show that TP ACLS with complex shape may be produced with OOA solutions without affecting mechanical performance. In fact, porosity levels of the consolidate ACLS are comparable with the initial prepreg despite of the absence of vacuum during molding. Moreover, high compressive stiffness was measured along both directions without observing damages, buckling or cracks in multiple tests. In the future, this kind of technology could be used for larger ACLSs by substituting the heat-shrink tube with a narrow tape to be wound as well after lamination.

scholarly journals Anisogrid lattice cylinders made of thermoplastic composite under buckling loading

2021 ◽  
Author(s):  
Leandro Iorio ◽  
Denise Bellisario ◽  
Nicola Gallo ◽  
Claudia Papa ◽  
Marco Regi ◽  
...  
Keyword(s):  
Shape Recovery ◽  
Lattice Structure ◽  
Glass Fibers ◽  
Thermoplastic Composite ◽  
Thermoplastic Composites ◽  
Vertical Loading ◽  
Geometrical Features ◽  
Polypropylene Matrix ◽  
Out Of Autoclave ◽  
Buckling Test

Anisogrid lattice cylinders have been produced by means of an innovative out-of-autoclave (OOA) process by using thermoplastic prepreg. Unidirectional thermoplastic tapes with polypropylene matrix and glass fibers were wound on cylindrical mandrels at room temperature. Composite consolidation was achieved by using the compression of a heat-shrink tube during its shape recovery in oven. A cylindrical anisogrid lattice structure was manufactured and mechanically tested under vertical loading. Results from the buckling test revealed the optimal adhesion between prepreg layers after the out-of-autoclave molding. Numerical modelling of buckling has been performed to correlate the structural behavior of the anisogrid lattice cylinder with composite material properties and geometrical features. A parametric model of the lattice structure has been defined for this aim. The proposed manufacturing technology combines the advantages of thermoplastic composites (reparability, easy handling, easy storage, long prepreg life, productivity) with the designing potential of anisogrid lattice structures in terms of lightness and stiffness.

scholarly journals Holding Pressure and Its Influence on Quality in PIM Technology

10.14311/1608 ◽  
2012 ◽  
Vol 52 (4) ◽  
Author(s):  
Pavel Petera
Keyword(s):  
Phase Separation ◽  
Injection Molding ◽  
Density Measurement ◽  
Powder Injection Molding ◽  
New Method ◽  
Powder Injection ◽  
Injection Molding Process ◽  
Molding Process

The PIM (powder injection molding) process consists of several steps in which faults can occur. The quality of the part that is produced usually cannot be seen until the end of the process. It is therefore necessary to find a way to discover the fault earlier in the process. The cause of defects is very often “phase separation” (inhomogeneity in powder distribution), which can also be influenced by the holding pressure. This paper evaluates the powder distribution with a new method based on density measurement. Measurements were made using various holding pressure values.

Effect of forming process on mechanical and interfacial properties for thermoplastic composite I-stiffened structures

2021 ◽  
pp. 095400832110515
Author(s):  
Guangming Dai ◽  
Lihua Zhan ◽  
Chenglong Guan ◽  
Minghui Huang
Keyword(s):  
Bonding Strength ◽  
Thermoplastic Composite ◽  
Thermoplastic Composites ◽  
Forming Process ◽  
Molding Process ◽  
Influencing Mechanism ◽  
Stiffened Structures ◽  
The Common ◽  
Polymer Aging

The forming process is the core factor to control the quality of thermoplastic composite components. In this paper, the common I-stiffened structures in the aerospace field were taken as the research object, and the forming process scheme was designed. Based on the prefabrication of C-shaped parts, the I-stiffened structures were prepared by the compression molding process. The influence law of molding temperature on the quality of the prefabricated C-shaped parts was explored. The time dependence of the PEEK melt viscosity was tested to provide the basis for the optimization of forming process parameters of I-stiffened structures. The influencing mechanism of thermoplastic composites repeatedly forming to the bonding strength of remelting interface was studied. The results show that repeated forming would lead to polymer aging and result in low bonding strength at the remelting interface of the I-stiffened structures. Optimizing the forming process could effectively reduce the aging of materials and improve the bonding strength of the remelting interface and overall mechanical properties of components. The research provides technical guidance for the manufacturing of complex thermoplastic composite components, especially the influence mechanism of the forming process on the bonding strength of remelting interface.

Design of a unitized thermoplastic composite out-of-autoclave three-bay wingbox demonstrator

2021 ◽  
Author(s):  
Vincenzo Oliveri ◽  
Giovanni Zucco ◽  
Mohammad Rouhi ◽  
Enzo Cosentino ◽  
Trevor Young ◽  
...  
Keyword(s):  
Thermoplastic Composite ◽  
Out Of Autoclave

Static and dynamic response of sandwich beams with lattice and pantographic cores

2021 ◽  
pp. 109963622110338
Author(s):  
Yury Solyaev ◽  
Arseniy Babaytsev ◽  
Anastasia Ustenko ◽  
Andrey Ripetskiy ◽  
Alexander Volkov
Keyword(s):  
Mechanical Performance ◽  
Lattice Structure ◽  
Unit Length ◽  
Experimental Tests ◽  
Plane Geometry ◽  
Sandwich Beams ◽  
Static Tests ◽  
Three Point Bending ◽  
The Core ◽  
The Impact

Mechanical performance of 3d-printed polyamide sandwich beams with different type of the lattice cores is investigated. Four variants of the beams are considered, which differ in the type of connections between the elements in the lattice structure of the core. We consider the pantographic-type lattices formed by the two families of inclined beams placed with small offset and connected by stiff joints (variant 1), by hinges (variant 2) and made without joints (variant 3). The fourth type of the core has the standard plane geometry formed by the intersected beams lying in the same plane (variant 4). Experimental tests were performed for the localized indentation loading according to the three-point bending scheme with small span-to-thickness ratio. From the experiments we found that the plane geometry of variant 4 has the highest rigidity and the highest load bearing capacity in the static tests. However, other three variants of the pantographic-type cores (1–3) demonstrate the better performance under the impact loading. The impact strength of such structures are in 3.5–5 times higher than those one of variant 4 with almost the same mass per unit length. This result is validated by using numerical simulations and explained by the decrease of the stress concentration and the stress state triaxiality and also by the delocalization effects that arise in the pantographic-type cores.

scholarly journals Smoothing additive manufactured parts using ns-pulsed laser radiation

2021 ◽  
Author(s):  
Florian Kuisat ◽  
Fernando Lasagni ◽  
Andrés Fabián Lasagni
Keyword(s):  
Surface Roughness ◽  
Mechanical Performance ◽  
State Of The Art ◽  
Pulsed Laser ◽  
Industrial Applications ◽  
Laser Source ◽  
Pulsed Laser Radiation ◽  
Current State ◽  
The Impact

AbstractIt is well known that the surface topography of a part can affect its mechanical performance, which is typical in additive manufacturing. In this context, we report about the surface modification of additive manufactured components made of Titanium 64 (Ti64) and Scalmalloy®, using a pulsed laser, with the aim of reducing their surface roughness. In our experiments, a nanosecond-pulsed infrared laser source with variable pulse durations between 8 and 200 ns was applied. The impact of varying a large number of parameters on the surface quality of the smoothed areas was investigated. The results demonstrated a reduction of surface roughness Sa by more than 80% for Titanium 64 and by 65% for Scalmalloy® samples. This allows to extend the applicability of additive manufactured components beyond the current state of the art and break new ground for the application in various industrial applications such as in aerospace.

scholarly journals Fused Deposition Modelling of Fibre Reinforced Polymer Composites: A Parametric Review

2021 ◽  
Vol 5 (1) ◽  
pp. 29
Author(s):  
Narongkorn Krajangsawasdi ◽  
Lourens G. Blok ◽  
Ian Hamerton ◽  
Marco L. Longana ◽  
Benjamin K. S. Woods ◽  
...  
Keyword(s):  
Process Parameters ◽  
Mechanical Performance ◽  
Fibre Length ◽  
Processing Parameters ◽  
Thermoplastic Composite ◽  
Fused Deposition Modelling ◽  
Layer By Layer ◽  
Fused Deposition ◽  
Fibre Reinforced Polymer ◽  
Printing Parameters

Fused deposition modelling (FDM) is a widely used additive layer manufacturing process that deposits thermoplastic material layer-by-layer to produce complex geometries within a short time. Increasingly, fibres are being used to reinforce thermoplastic filaments to improve mechanical performance. This paper reviews the available literature on fibre reinforced FDM to investigate how the mechanical, physical, and thermal properties of 3D-printed fibre reinforced thermoplastic composite materials are affected by printing parameters (e.g., printing speed, temperature, building principle, etc.) and constitutive materials properties, i.e., polymeric matrices, reinforcements, and additional materials. In particular, the reinforcement fibres are categorized in this review considering the different available types (e.g., carbon, glass, aramid, and natural), and obtainable architectures divided accordingly to the fibre length (nano, short, and continuous). The review attempts to distil the optimum processing parameters that could be deduced from across different studies by presenting graphically the relationship between process parameters and properties. This publication benefits the material developer who is investigating the process parameters to optimize the printing parameters of novel materials or looking for a good constituent combination to produce composite FDM filaments, thus helping to reduce material wastage and experimental time.

scholarly journals A Comprehensive Investigation on 3D Printing of Polyamide 11 and Thermoplastic Polyurethane via Multi Jet Fusion

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2139
Author(s):  
Wei Shian Tey ◽  
Chao Cai ◽  
Kun Zhou
Keyword(s):  
Tensile Strength ◽  
Flexural Strength ◽  
Wear Rate ◽  
Mechanical Performance ◽  
Thermoplastic Polyurethane ◽  
Print Quality ◽  
Polyamide 11 ◽  
Powder Bed

Multi Jet Fusion (MJF) is a recently developed polymeric powder bed fusion (PBF) additive manufacturing technique that has received considerable attention in the industrial and scientific community due to its ability to fabricate functional and complex polymeric parts efficiently. In this work, a systematic characterization of the physicochemical properties of MJF-certified polyamide 11 (PA11) and thermoplastic polyurethane (TPU) powder was conducted. The mechanical performance and print quality of the specimens printed using both powders were then evaluated. Both PA11 and TPU powders showed irregular morphology with sharp features and had broad particle size distribution, but such features did not impair their printability significantly. According to the DSC scans, the PA11 specimen exhibited two endothermic peaks, while the TPU specimen exhibited a broad endothermic peak (116–150 °C). The PA11 specimens possessed the highest tensile strength in the Z orientation, as opposed to the TPU specimens which possessed the lowest tensile strength along the same orientation. The flexural properties of the PA11 and TPU specimens displayed a similar anisotropy where the flexural strength was highest in the Z orientation and lowest in the X orientation. The porosity values of both the PA11 and the TPU specimens were observed to be the lowest in the Z orientation and highest in the X orientation, which was the opposite of the trend observed for the flexural strength of the specimens. The PA11 specimen possessed a low coefficient of friction (COF) of 0.13 and wear rate of 8.68 × 10−5 mm3/Nm as compared to the TPU specimen, which had a COF of 0.55 and wear rate of 0.012 mm3/Nm. The PA11 specimens generally had lower roughness values on their surfaces (Ra < 25 μm), while the TPU specimens had much rougher surfaces (Ra > 40 μm). This investigation aims to uncover and explain phenomena that are unique to the MJF process of PA11 and TPU while also serving as a benchmark against similar polymeric parts printed using other PBF processes.

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