Strength development versus process data in ultrasonic welding of thermoplastic composites with flat energy directors and its application to the definition of optimum processing parameters

2014 ◽  
Vol 65 ◽  
pp. 27-37 ◽  
Author(s):  
Irene Fernandez Villegas
Keyword(s):  
Processing Parameters ◽  
Ultrasonic Welding ◽  
Thermoplastic Composites ◽  
Strength Development ◽  
Process Data ◽  
Optimum Processing ◽  
Definition Of

scholarly journals Advances in Ultrasonic Welding of Thermoplastic Composites: A Review

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1284 ◽  
Author(s):  
Somen K. Bhudolia ◽  
Goram Gohel ◽  
Kah Fai Leong ◽  
Aminul Islam
Keyword(s):  
Composite Structures ◽  
Dissimilar Materials ◽  
Processing Parameters ◽  
Ultrasonic Welding ◽  
Thermoplastic Composite ◽  
Thermoplastic Composites ◽  
Pressure Amplitude ◽  
Advantages And Disadvantages ◽  
Cost Efficient ◽  
Weld Time

The ultrasonic welding (UW) technique is an ultra-fast joining process, and it is used to join thermoplastic composite structures, and provides an excellent bonding strength. It is more cost-efficient as opposed to the conventional adhesive, mechanical and other joining methods. This review paper presents the detailed progress made by the scientific and research community to date in the direction of the UW of thermoplastic composites. The focus of this paper is to review the recent development of the ultrasonic welding technique for thermoplastic composites to thermoplastic composites, and to dissimilar materials. Different ultrasonic welding modes and their processing parameters, namely, weld time, weld pressure, amplitude, type of energy directors (EDs) affecting the welding quality and the advantages and disadvantages of UW over other bonding techniques, are summarized. The current state of the ultrasonic welding of thermoplastic composites and their future perspectives are also deliberated.

scholarly journals Review: Filament Winding and Automated Fiber Placement with In Situ Consolidation for Fiber Reinforced Thermoplastic Polymer Composites

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1951
Author(s):  
Yi Di Boon ◽  
Sunil Chandrakant Joshi ◽  
Somen Kumar Bhudolia
Keyword(s):  
Processing Parameters ◽  
Filament Winding ◽  
Reference Points ◽  
Thermoplastic Composites ◽  
Manufacturing Processes ◽  
Fiber Reinforced ◽  
Consolidation Process ◽  
Fiber Placement ◽  
Automated Fiber Placement

Fiber reinforced thermoplastic composites are gaining popularity in many industries due to their short consolidation cycles, among other advantages over thermoset-based composites. Computer aided manufacturing processes, such as filament winding and automated fiber placement, have been used conventionally for thermoset-based composites. The automated processes can be adapted to include in situ consolidation for the fabrication of thermoplastic-based composites. In this paper, a detailed literature review on the factors affecting the in situ consolidation process is presented. The models used to study the various aspects of the in situ consolidation process are discussed. The processing parameters that gave good consolidation results in past studies are compiled and highlighted. The parameters can be used as reference points for future studies to further improve the automated manufacturing processes.

scholarly journals Static ultrasonic welding of carbon fibre unidirectional thermoplastic materials and the influence of heat generation and heat transfer

2021 ◽  
pp. 002199832097681
Author(s):  
F Köhler ◽  
IF Villegas ◽  
C Dransfeld ◽  
A Herrmann
Keyword(s):  
Cross Sections ◽  
Weld Line ◽  
Welding Process ◽  
Ultrasonic Welding ◽  
Thermoplastic Composites ◽  
Squeeze Flow ◽  
Anisotropic Flow ◽  
Lap Shear ◽  
Anisotropic Thermal Conductivity ◽  
Edge Defects

Ultrasonic welding is a promising technology to join fibre-reinforced thermoplastic composites. While current studies are mostly limited to fabric materials the applicability to unidirectional materials, as found in aerospace structures, would offer opportunities for joining primary aircraft structures. However, due to the highly anisotropic flow of a molten unidirectional ply undesired squeeze flow phenomena can occur at the edges of the weld overlap. This paper investigates how the fibre orientation in the plies adjacent to the weld line influences the welding process and the appearance of edge defects. Ultrasonic welding experiments with different layups and energy director configurations were carried out while monitoring temperatures at different locations inside and outside the weld overlap. The joints were characterized by single lap shear tests, analysis of corresponding fracture surfaces and microscopic cross-sections. Results showed that the anisotropic flow and the anisotropic thermal conductivity of the plies adjacent to the weld line have a distinct effect on the appearance and location of edge defects. By using energy directors that cover only part of the weld overlap area a new approach was developed to mitigate edge defects caused by the highly directional properties of the unidirectional plies.

Determination of optimal microwave curing cycle for fly ash mortars

2008 ◽  
Vol 35 (4) ◽  
pp. 349-357 ◽  
Author(s):  
İlker Bekir Topçu ◽  
Mehmet Uğur Toprak ◽  
Devrim Akdağ
Keyword(s):  
Fly Ash ◽  
Processing Parameters ◽  
Microwave Energy ◽  
Strength Prediction ◽  
Strength Development ◽  
Microwave Curing ◽  
Optimal Processing ◽  
Cement Mortars ◽  
Curing Cycle

Microwave energy can accelerate the hydration of cement, which results in the rapid strength development of concrete. In this paper, prediction of later age compressive strength of fly ash cement mortars, based on the accelerated strength of mortars cured with microwave energy, was investigated. To accelerate curing properly, optimal processing parameters of microwave curing (MC) on Portland cement mortars (CM) and fly ash cement mortars (FA) were first determined and then were applied to mortars. The possible early ages for the strength prediction were found to be at 6 and 8 h for CM and FA, respectively. The error percentages for prediction of CM were ±2.22% and 2.91% for 7 and 28 d, respectively. Error percentages for FA, on the other hand, were ±4.36% and 5.20% for 7 and 28 d, respectively.

scholarly journals Development of Laser-Based Powder Bed Fusion Process Parameters and Scanning Strategy for New Metal Alloy Grades: A Holistic Method Formulation

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2356 ◽  
Author(s):  
Elena Bassoli ◽  
Antonella Sola ◽  
Mattia Celesti ◽  
Sandro Calcagnile ◽  
Carlo Cavallini
Keyword(s):  
Processing Parameters ◽  
Powder Bed Fusion ◽  
Scanning Strategy ◽  
Industrial Practice ◽  
Powder Bed ◽  
Complete Test ◽  
Specific Geometry ◽  
Method Formulation ◽  
Definition Of ◽  
Standard Energy

In spite of the fast growth of laser-based powder bed fusion (L-PBF) processes as a part of everyday industrial practice, achieving consistent production is hampered by the scarce repeatability of performance that is often encountered across different additive manufacturing (AM) machines. In addition, the development of novel feedstock materials, which is fundamental to the future growth of AM, is limited by the absence of established methodologies for their successful exploitation. This paper proposes a structured procedure with a complete test plan, which defines step-by-step the standardized actions that should be taken to optimize the processing parameters and scanning strategy in L-PBF of new alloy grades. The method is holistic, since it considers all the laser/material interactions in different local geometries of the build, and suggests, for each possible interaction, a specific geometry for test specimens, standard energy parameters to be analyzed through a design of experiment, and measurable key performance indicators. The proposed procedure therefore represents a sound and robust aid to the development of novel alloy grades for L-PBF and to the definition of the most appropriate processing conditions for them, independent of the specific AM machine applied.

scholarly journals FOUND: A DEFINITION OF INTELLIGENCE

2021 ◽  
Vol IV(1) ◽  
Author(s):  
Adewunmi Falode ◽  
Keyword(s):  
21St Century ◽  
Pivotal Role ◽  
Process Data ◽  
Effective Utilization ◽  
Qualitative And Quantitative ◽  
Political Group ◽  
Military Planning ◽  
Critical Edge ◽  
State Actors ◽  
Definition Of

Intelligence has come to play a pivotal role in the affairs of states and non-state actors in the 21st century. It not only determines the outcome of conflict when it breaks out but also provides critical edge and foresight in military planning and engagements. However, the effective utilization and deployment of intelligence in any strategic environment may be hampered by the lack of a holistic and generally accepted definition of it. The search for a robust definition has not also been helped by the differing views on what should constitute the basic elements of it. To overcome these challenges, this work argues for and provides a holistic definition of intelligence. It uses both qualitative and quantitative methodologies to provide a more robust and holistic definition of intelligence. The work concludes that any acceptable definition of intelligence must contain five key elements: process, data, actionable information, political group and security.

Modeling and Numerical Simulation of Laminated Thermoplastic Composites Manufactured by Laser-Assisted Automatic Tape Placement

2020 ◽  
Vol 35 (5) ◽  
pp. 471-480
Author(s):  
G. Ausias ◽  
G. Dolo ◽  
D. Cartié ◽  
F. Challois ◽  
P. Joyot ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Numerical Model ◽  
Pressure Field ◽  
Processing Parameters ◽  
Thermoplastic Composites ◽  
Final Thickness ◽  
Intimate Contact ◽  
Polymer Flow ◽  
Compaction Force ◽  
Heat Transfer Simulation

Abstract A comprehensive numerical model is developed for the simulation of the laser-assisted automated tape placement process of carbon fiber/thermoplastic composites. After being heated with a laser, the thermoplastic is welded with the help of a consolidation roller onto a substrate made up of layers of tapes bonded onto one another. Under the pressure applied by the roller, the thermoplastic flows and the tape reaches its final thickness. The numerical model is developed in three sequential steps that can be used to identify the required pressure and temperature distribution to achieve a good bond. Firstly, a heat transfer simulation is performed to determine the temperature distribution into the incoming tape under the consolidation roller. Secondly, a rheological model is developed to examine the polymer flow under the roller and to obtain the pressure field. Finally, the consolidation level between the substrate and the tape is investigated through the degree of intimate contact, which is related to the processing parameters such as the roller velocity, the laser power density and the compaction force.

Laser Assisted Cold Bending of High Strength Steels

2014 ◽  
Author(s):  
Erica Liverani ◽  
Alessandro Ascari ◽  
Alessandro Fortunato ◽  
Adrian Lutey
Keyword(s):  
Heat Treatment ◽  
High Strength Steels ◽  
High Strength ◽  
Processing Parameters ◽  
Cold Forming ◽  
Steel Sheets ◽  
Phase Lead ◽  
Cold Bending ◽  
Bending Process ◽  
Definition Of

This paper presents the feasibility of an innovative application of laser-assisted bending process. The high strength steel sheets bending, carried out after a laser heat treatment, is studied. Several strategies aimed at obtaining a ductile structure along the bending line, suitable for cold forming, are investigated. The influence of laser processing parameters on the microstructure, hardness and strength of the sheets are discussed and analyzed. In order to predict the temperature and ensure the repeatability and reliability of the process, a model for heat treatment simulation is developed. The study of the experimental data and the integration with the simulation of the heating phase lead to the definition of specific process parameters suitable for achieving a crack-free cold bending of high strength steels.

The Authentic Coaching Model: A Grounded Theory of Coaching

2014 ◽  
Vol 1 (2) ◽  
pp. 61-74 ◽  
Author(s):  
Steven C. Barnson
Keyword(s):  
The United States ◽  
Team Sport ◽  
Process Data ◽  
Coaching Model ◽  
Coaching Process ◽  
Definition Of ◽  
Sport Coaches ◽  
Sports Coaching ◽  
School Team ◽  
Over Time

The purpose of this research was to: (a) describe the coaching process using language that is meaningful for practicing coaches; (b) explain how different coaches maneuver through the process of coaching; and (c) probe the paradoxical nature of the coaching process. Data gathered over a 6-month period with eight high school team sport coaches in the United States representing six different sport contexts, revealed three foundational paradoxes. Based on the results, coaching is best viewed as the convergence of three paradoxical forces: the paradox of authenticity, the paradox of purpose, and the pendulum paradox. The paper closes with the suggested definition of sports coaching: Coaching is the process of utilizing an intentional philosophic approach to simultaneously teach, motivate, and organize an athlete to attain higher levels of success over time.

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