scholarly journals Laser Welding of Transmitting High-Performance Engineering Thermoplastics

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 402
Author(s):  
Fábio A.O. Fernandes ◽  
António B. Pereira ◽  
Bernardo Guimarães ◽  
Tiago Almeida
Keyword(s):  
Laser Welding ◽  
High Performance ◽  
High Reliability ◽  
High Strength ◽  
Cost Effective ◽  
Tensile Tests ◽  
Performance Engineering ◽  
Theoretical Approaches ◽  
Base Method ◽  
And Performance

Laser processing is a rapidly growing key technology driven by several advantages such as cost and performance. Laser welding presents numerous advantages in comparison with other welding technologies, providing high reliability and cost-effective solutions. Significant interest in this technology, combined with the increasing demand for high-strength lightweight structures has led to an increasing interest in joining high-performance engineering thermoplastics by employing laser technologies. Laser transmission welding is the base method usually employed to successfully join two polymers, a transmitting one through which the laser penetrates, and another one responsible for absorbing the laser radiation, resulting in heat and melting of the two components. In this work, the weldability of solely transmitting high-performance engineering thermoplastic is analyzed. ERTALON® 6 SA, in its white version, is welded by a pulsed Nd:YAG laser. Tensile tests were performed in order to evaluate the quality of each joint by assessing its strength. A numerical model of the joint is also developed to support the theoretical approaches employed to justify the experimental observations.

A STUDY OF SURFACE FINISHES FOR IC SUBSTRATES AND WIRE BOND APPLICATIONS

2011 ◽  
Vol 2011 (1) ◽  
pp. 000516-000520 ◽  
Author(s):  
John Ganjei ◽  
Ernest Long ◽  
Lenora Toscano
Keyword(s):  
Surface Finish ◽  
Printed Circuit Boards ◽  
Performance Enhancement ◽  
High Reliability ◽  
Cost Effective ◽  
Electroless Nickel ◽  
Gold Wire ◽  
Electronics Industry ◽  
Surface Finishes ◽  
And Performance

The continuing drive for ever increasing performance enhancement in the electronics industry, in combination with the recent, very significant increase in precious metal costs have left fabricators and OEMs questioning what the best, most cost effective, surface finish is for high reliability applications. Currently, the IC substrate market relies heavily on electrolytic nickel and gold as a solderable and superior wire bondable surface. The use of this finish has allowed manufacturers to avoid the reliability concerns However, this choice also results in significant design restraints being imposed. Many in the industry are now investigating the use of electroless nickel/electroless palladium/immersion gold (ENEPIG) to achieve both high reliability and performance, without the negative design restraints imparted by the use of electrolytic processes. However, over the last year alone, the industry has watched the price of gold increase by 50% and that of palladium double [1]. With this in mind, and considering the historic precedent set in the mid 1990’s when ENEPIG was also evaluated as a surface finish for printed circuit boards, when coincidentally, the cost of palladium also reached an all time high, it should be remembered that the electronics industry quickly moved to evaluate alternate, more cost sustainable, surface finishes. This paper details the use of lower cost, alternate surface finishes for IC substrate applications, with particular experimental focus on gold wire bonding capabilities and BGA solderability of the finishes described. The paper also discusses related process cycle advantages and the significantly reduced operating costs associated with these new finishes.

Optimization of Structural Design for High-Performance Concrete Bridges

1998 ◽  
Vol 1624 (1) ◽  
pp. 132-139
Author(s):  
Mary Lou Ralls ◽  
Ramon L. Carrasquillo ◽  
Ned H. Burns
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Cost Effective ◽  
Concrete Bridges ◽  
Practical Guidelines ◽  
Improved Performance ◽  
Maintenance Requirements ◽  
Design And Construction

High-performance concrete (HPC) bridges can be cost-effective both initially and in the long term, provided the design and construction optimize the improved performance characteristics of HPC. Using the high-strength characteristic of HPC can reduce the required number and size of beams. Using the improved durability characteristics of HPC can reduce maintenance requirements and extend the service life. Practical guidelines help design and construction engineers implement HPC in bridges.

scholarly journals Ground Glass Pozzolan in Conventional, High, and Ultra-High Performance Concrete

2018 ◽  
Vol 149 ◽  
pp. 01005 ◽  
Author(s):  
Arezki Tagnit-Hamou ◽  
Ablam Zidol ◽  
Nancy Soliman ◽  
Joris Deschamps ◽  
Ahmed Omran
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Ground Glass ◽  
Strengthening Effect ◽  
Ultra High Performance Concrete ◽  
Conventional Concrete ◽  
Supplementary Cementitious Material ◽  
Pozzolanic Material ◽  
And Performance

Ground-glass pozzolan (G) obtained by grinding the mixed-waste glass to same fineness of cement can act as a supplementary-cementitious material (SCM), given that it is an amorphous and a pozzolanic material. The G showed promising performances in different concrete types such as conventional concrete (CC), high-performance concrete (HPC), and ultra-high performance concrete (UHPC). The current paper reports on the characteristics and performance of G in these concrete types. The use of G provides several advantages (technological, economical, and environmental). It reduces the production cost of concrete and decrease the carbon footprint of a traditional concrete structures. The rheology of fresh concrete can be improved due to the replacement of cement by non-absorptive glass particles. Strength and rigidity improvements in the concrete containing G are due to the fact that glass particles act as inclusions having a very high strength and elastic modulus that have a strengthening effect on the overall hardened matrix.

Thermoplastic Elastomer Compounds from Sulfonated EPDM Ionomers

1988 ◽  
Vol 61 (2) ◽  
pp. 223-237 ◽  
Author(s):  
A. U. Paeglis ◽  
F. X. O'Shea
Keyword(s):  
High Performance ◽  
High Strength ◽  
Thermoplastic Elastomer ◽  
Cost Effective ◽  
Thermoplastic Elastomers ◽  
Hot Air ◽  
Low Temperature Flexibility ◽  
High Performance Application ◽  
And Control ◽  
Thermal Reversibility

Abstract The zinc sulfonate of EPDM, an ionic elastomer polymer, can be readily formulated into useful thermoplastic elastomer compounds having beneficial properties and processing characteristics. The thermoplastic processing characteristics of these ionic elastomers are uniquely controlled by “ionolyzers,” preferential ionic plasticizers. These additives induce thermal reversibility in the ionic crosslink and control the response of the ionic associations to temperature. Ionic elastomer compounds maintain many of the performance features characteristic of vulcanized EPDM, such as low-temperature flexibility, thermal stability, and weatherability, while providing the added advantages of heat weldability and elimination of vulcanization. We have developed a cost-effective ionic elastomer formulation that meets or exceeds the RMA recommendations for black EPDM in a demanding, high performance application, single-ply roofing membrane. High-strength lap seams can be rapidly fabricated using portable hot air welders, a technique unavailable to conventional vulcanized EPDM sheet. Other applications have been investigated for these polymers, such as hose, footwear, mechanical goods, adhesives, impact modifiers, and asphalt modifiers both as thermoplastic elastomers and as modifiers for other materials. These applications have taken advantage of the unique rheological and solubility properties of these polymers. In addition, a new polymer grade offers an advance in the ability to formulate higher strength and more highly filled and extended ionic elastomer compositions.

Investigation of Residual Stresses Distribution in Titanium Weldments

2014 ◽  
Vol 777 ◽  
pp. 171-175 ◽  
Author(s):  
Shao Pin Song ◽  
Anna M. Paradowska ◽  
Ping Sha Dong
Keyword(s):  
Residual Stresses ◽  
High Performance ◽  
Weight Ratio ◽  
Welding Process ◽  
High Strength ◽  
Naval Research ◽  
Office Of Naval Research ◽  
And Performance ◽  
Superior Corrosion Resistance ◽  
The University

Titanium and its alloys have increasingly become a material of choice for applications in high-performance structures due to their superior corrosion resistance and high strength-to-weight ratio. However, in contrast to conventional steel alloys, there exist little design and manufacturing experience in the heavy fabrication industry with large welded structures made of titanium materials. In addressing the above concern, the University of New Orleans funded by Office of Naval Research (ONR) initiated program on investigation of manufacturability and performance of a titanium mid-ship section. The uniqueness of this program is its focus upon a representative full-size mid-ship section upon which relevant scientific and technological challenges are simulated and experimentally validated. This paper reports the measurements of residual stresses using neutron diffraction in titanium T-joints. The residual stresses were measured using Engin-X at ISIS (UK) and the Kowari Strain Scanner at ANSTO (Australia). This experimental research was used to validate our in house predictions and significantly improved the knowledge and understanding of the welding process of titanium alloys.

scholarly journals Low-Energy and Modular Wearable Device for Wireless Measurement of Physiological Signals

2020 ◽  
Vol 2 (1) ◽  
pp. 75
Author(s):  
Manuel A. Herrera-Juárez ◽  
Roberto G. Ramírez-Chavarría
Keyword(s):  
High Performance ◽  
High Reliability ◽  
Processing System ◽  
Cost Effective ◽  
Low Energy ◽  
Physiological Signals ◽  
Data Streaming ◽  
Wireless Data ◽  
Notification System ◽  
Promising Tool

The most common way for accessing healthcare and monitoring physiological signals is based on commercial devices. Most of them are, in general, expensive, highly invasive, and require sophisticated infrastructure for operating. Nowadays, wearable devices (WD) offer an attractive technology for circumventing the limitations of classic medical devices. The design of WD, however, remains a challenging task to reach high-performance, reliability, and to be ergonomic. In this work, we develop, to the best of our knowledge, a novel WD with two main highlights. (i) Our device is based on a low-power 32-bit microcontroller, embedding a Bluetooth Low Energy (BLE) module for wireless data streaming with a mobile application for signal monitoring and recording, alongside a warning notification system. (ii) The proposed WD has a modular and flexible design, such that the user can increase the number of sensors by sharing the acquisition and processing system, thus reducing the hardware requirements and exhibiting a minimally invasive arrangement. For all the WD stages, we show their design methodology, the tests for characterizing their performance, and the results obtained from a case of study. For the latter, we consider two sensor prototypes for measuring the corporal temperature with a passive sensor, as well as the breath and heart rates via photoplethysmography signals. Results show that our WD is a cost-effective alternative and a promising tool for healthcare monitoring, as it operates in agreement with physiological levels with high-reliability.

scholarly journals Challenges and Opportunities in Remote Laser Welding of Steel to Aluminium

2019 ◽  
Vol 269 ◽  
pp. 02012 ◽  
Author(s):  
Hiren R. Kotadia ◽  
Pasquale Franciosa ◽  
Dariusz Ceglarek
Keyword(s):  
Laser Welding ◽  
Aluminium Alloys ◽  
High Performance ◽  
Cost Savings ◽  
Critical Factor ◽  
Cost Effective ◽  
Automotive Body ◽  
Design Flexibility ◽  
Challenges And Opportunities ◽  
Remote Laser Welding

In the last two decades, the automotive industry has been facing demands to reduce fuel consumption and to meet CO2 emissions through applications of lightweight materials. Therefore, aluminium alloys have replaced substantial amounts of steel; and they are receiving significant attention to achieve greenhouse emission targets. However, a critical factor in applications of advanced aluminium in automotive Body in White (BIW) designs depends on availability of cost effective and high performance joining processes. Currently, a Self-Pierce Riveting (SPR) process is extensively used for aluminium BIW sheet metal parts joining which is expensive, additionally increase the weight of the vehicle and cause inefficiency in manufacturing operations. As aluminium alloys are difficult to weld by conventional technologies such as electrical resistance spot welding, MIG arc welding etc., various joining technologies had proposed to weld aluminium alloys and dissimilar alloys over the years. Often, these technologies restrict design flexibility and are expensive for mass production. In this context, Remote Laser Welding (RLW) has gained popularity because of its distinct advantages such as design flexibility, production speed, material and cost savings. This paper provides a critical review of challenges and opportunities for application of RLW to dissimilar metal welding of steel to aluminium. Next steps of research and development are also highlighted.

scholarly journals Development of the “High Pressure Repair Dome” system for in-situ high performance repair of aeronautic structures

2018 ◽  
Vol 188 ◽  
pp. 04004
Author(s):  
Nicola Gallo ◽  
Silvio Pappadá ◽  
Umberto Raganato ◽  
Stefano Corvaglia
Keyword(s):  
High Pressure ◽  
High Performance ◽  
Stress Transfer ◽  
Cost Effective ◽  
Reliable Technique ◽  
Structural Repair ◽  
Aerospace Applications ◽  
And Performance ◽  
Curing Cycle

As the use of composites for high-performance structures for aerospace applications is constantly increasing, together with the complexity and scale of such structures, an increasingly effort is carried out for the development of advanced techniques for composites structural repair. Mechanical loads and environmental conditions often cause composite damages. If material damage is not extensive, structural repair is the most cost-effective solution. Composite patches can be mechanically fastened, adhesively bonded or co-cured. Bonding or co-curing process provides enhanced stress transfer mechanisms, joint efficiencies and aerodynamic performance. In this paper an innovative and reliable technique to repair damaged composite aeronautical components, named High Pressure Repair Dome (HPRD), is shown. The innovative aspect of this solution is the possibility to bond or co-cure a composite prepreg patch under a pressurized dome, thus using a prepreg compatible with the composite structure. HPRD was developed to allow in-situ repairing on full-scale structures, with the possibility of an accurate control of the parameters of the curing cycle. The advantages and performance of HPRD approach will be discussed and compared with traditional techniques, describing the results achieved and the activity on-course for the full industrialization of this system.

scholarly journals Tensile Properties of AM Maraging steel

2018 ◽  
Vol 183 ◽  
pp. 01058 ◽  
Author(s):  
Philip Church ◽  
Mark Reynolds ◽  
Peter Gould ◽  
Robin Oakley ◽  
Nigel Harrison ◽  
...  
Keyword(s):  
Maraging Steel ◽  
Economies Of Scale ◽  
Split Hopkinson Pressure Bar ◽  
High Strength ◽  
Cost Effective ◽  
Tensile Tests ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Graded Materials ◽  
Pressure Bar

Additively Manufactured (AM) materials have great potential for producing graded materials, embedded structures and near net complex shapes. AM maraging steel properties have been compared with wrought maraging steel. The comparison featured interrupted tensile tests over a range of temperatures and strain rates. In addition a specially designed Tensile Split Hopkinson Pressure Bar (TSHPB) has been built to test very high strength metals at high strain rates. The results showed that the AM maraging steel was much more ductile than expected and exhibited significant necking under all conditions tested. All the samples exhibited ductile fracture. Although not as ductile as the wrought material, the AM material could be cost effective through economies of scale for complex components. The microstructure contained inclusions which derived from either the powder or the AM process and thus there is significant potential to improve these materials further. A modified Armstrong-Zerilli model was also constructed for these materials and shown to predict the raw experimental data within experimental error using DYNA3D simulations.

An Improved Size, Matching, and Scaling Method for the Design of Deterministic Mesoscale Truss Structures

2011 ◽  
Author(s):  
Patrick S. Chang ◽  
David W. Rosen
Keyword(s):  
High Performance ◽  
Design Method ◽  
Weight Ratio ◽  
High Strength ◽  
Original Method ◽  
Topological Optimization ◽  
Truss Structures ◽  
Scaling Method ◽  
Element Analysis ◽  
And Performance

Mesoscale truss structures are cellular structures that have support elements on the order of centimeters. These structures are engineered for high performance and have applications in industries where a high strength-to-weight ratio is desired. However, design of mesoscale truss structures currently requires some form of topological optimization that slows the design process. In previous research, a new Size, Matching and Scaling method was presented that eliminated the need for topological optimization by using a solid-body finite element analysis combined with a library of lattice configurations to generate topologies. When compared to topological optimization, results were favorable: design times were significantly reduced and performance results were comparable. In this paper, we present a modified Size Matching and Scaling design method that addresses key issues in the original method. Firstly, we outline an improve methodology. Secondly, we expand the library of configurations in order to improve lattice performance. Finally, we test the updated method and library against design examples.

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