Browse Topic: Lasers

Items (2,178)
This specification covers an alpha-beta Ti-6Al-4V alloy produced by laser powder bed fusion (L-PBF) additive manufacturing and subjected to hot isostatic press (HIP) operation. Typically, this material is used for complex-shaped aerospace products made to near net shape dimensions. These products have been used typically for parts requiring operating strength up to 750 °F (399 °C), but usage is not limited to such applications
AMS AM Additive Manufacturing Metals
ABSTRACT The objective in this paper is to understand the challenges of making additive manufacturing a future source of supply for the Department of Defense through the redesign of a part for metal laser Powder Bed Fusion. The scope of this paper involved the redesign of a single cast-and-machined part for an Army ground vehicle system. The component was redesigned using topology optimization based on suitable replacement materials and design data from the representative part. In parallel, a brief review of AM standards identified a process to qualify the component through post-processing, non-destructive evaluation, and witness testing. Alongside this redesign analysis, a brief cost analysis was conducted to understand the cost associated with manufacturing and qualifying this part for multiple AM materials. The resulting analysis demonstrated that for this component, which was subject to high design loads, Scalmalloy, Ti-6Al-4V, and 17-4PH Stainless Steel could produce the most cost
Burke, RorySimpson, Timothy
ABSTRACT A new integrated testing system for the validation of stochastic vehicle-snow interaction models is presented in this paper. The testing system consists of an instrumented test vehicle, vehicle-mounted laser profilometer and a snow micropenetrometer. The test vehicle is equipped on each tire with a set of 6-axis wheel transducers, and a GPS-based data logger tracks vehicle motion. Data is also simultaneously acquired from the sensors from the test vehicle’s Electronic Stability Program. The test vehicle provides measurements that include three forces and moments at each wheel center, vehicle body slip angle, speed, acceleration, yaw rate, roll, and pitch. The profilometer has a 3-D scanning laser and an Inertial Measurement Unit to compensate for vehicle motion. Depth of snow cover, profile of snow surface and wheel sinkage can be obtained from the profilometer. The snow micropenetrometer measures the strength of the snow cover before and after vehicle traversal. Preliminary
Lee, Jonah H.Johnson, Thomas H.Huang, DaisyMeurer, StephenReid, Alexander A.Meldrum, Bill R.
Lasers are essential tools for observing, detecting, and measuring things in the natural world that we can’t see with the naked eye. But the ability to perform these tasks is often restricted by the need to use expensive and large instruments
In physical chemistry, time-resolved spectroscopy is the study of dynamic processes in materials or chemical compounds. Within this field, various techniques including transient absorption spectroscopy are used to study the mechanistic and kinetic details of chemical processes that occur within just a few picoseconds to a femtosecond — the equivalent of one millionth of one billionth of a second
Manufacturing flaws and microstructure irregularities pose challenges for the widespread adoption of metal additive manufacturing (MAM) in the US Army. These issues stem from the influence of melt-pool dynamics on the properties of 3D-printed metal parts, which are highly dependent on multiple process parameters. This paper investigates the potential of using electromagnetic fields (EM) to control the melt-pool dynamics in MAM, aiming to eliminate flaws and irregularities. A novel technique is proposed, involving a coil and strategically positioned permanent magnets to actively churn the melt pool. Initial validation of this approach was conducted using COMSOL Multiphysics® through simulation modeling, with ongoing efforts for experimental verification. The findings indicate promising opportunities for enhancing the consistency of 3D printed parts
Karpenko, OleksiiUdpa, SatishUdpa, LalitaHaq, Mahmood
Researchers worldwide are currently working on the next evolution of communication networks, called “beyond 5G” or 6G networks. To enable the near-instantaneous communication needed for applications like augmented reality or the remote control of surgical robots, ultra-high data speeds will be needed on wireless channels. In a study published recently in IEICE Electronics Express, researchers from Osaka University and IMRA AMERICA have found a way to increase these data speeds by reducing the noise in the system through lasers
Today, advancements in industrial laser cleaning automation show great promise in boosting productivity and safety when rust and contaminant removal or surface preparation is required for higher volumes of components and equipment
Space lasers are transforming the world. Not the far-off future of science fiction, but the universe of how data and communications flow today - everywhere from deep space missions to countless applications here on earth, including consumer internet services, military operations, and banking transactions. Lasers can transmit vast amounts of data over great distances at the speed of light, 100 times faster than previously possible in space. The narrowness of the light beams makes laser communication remarkably efficient. The highly focused light is aimed at the receiver, resulting in minimal beam divergence and signal loss and allowing for reduced power consumption
Riding aboard NASA's Psyche spacecraft, the agency's Deep Space Optical Communications technology demonstration continues to break records. While the asteroid-bound spacecraft doesn't rely on optical communications to send data, the new technology has proven that it's up to the task. After interfacing with the Psyche's radio frequency transmitter, the laser communications demo sent a copy of engineering data from over 140 million miles (226 million kilometers) away, 1. times the distance between Earth and the Sun. This achievement provides a glimpse into how spacecraft could use optical communications in the future, enabling higher-data-rate communications of complex scientific information as well as high-definition imagery and video in support of humanity's next giant leap: sending humans to Mars
Riding aboard NASA’s Psyche spacecraft, the agency’s Deep Space Optical Communications technology demonstration continues to break records. While the asteroid-bound spacecraft doesn’t rely on optical communications to send data, the new technology has proven that it’s up to the task. After interfacing with the Psyche’s radio frequency transmitter, the laser communications demo sent a copy of engineering data from over 140 million miles (226 million kilometers) away, 1½ times the distance between Earth and the Sun
The photochemical etching (PCE) process is distinguished by its capacity to fabricate metal parts with unparalleled accuracy. This process sidesteps the typical stresses and deformations linked to conventional metal-working, like stamping or laser cutting, which can compromise material integrity. Such fidelity is crucial in the manufacture of components for thermal management systems, where material integrity and component precision are non-negotiable for ensuring effective heat creation or dissipation. PCE’s ability to craft parts with smooth, burr-free edges and exact dimensions means heat management components work more effectively, bolstering the reliability and extending the service life of micro electronic devices
Selective Laser Melting (SLM) has gained widespread usage in aviation, aerospace, and die manufacturing due to its exceptional capacity for producing intricate metal components of highly complex geometries. Nevertheless, the instability inherent in the SLM process frequently results in irregularities in the quality of the fabricated components. As a result, this hinders the continuous progress and broader acceptance of SLM technology. Addressing these challenges, in-process quality control strategies during SLM operations have emerged as effective remedies for mitigating the quality inconsistencies found in the final components. This study focuses on utilizing optical emission spectroscopy and IR thermography to continuously monitor and analyze the SLM process within the powder bed, intending to strengthen process control and minimize defects. Optical emission spectroscopy is employed to study the real-time interactions between the laser and powder bed, melt pool dynamics, material
Raju, BenjaminKancherla, Kishore BabuB S, DakshayiniRoy Mahapatra, Debiprosad
The Selective Laser Melting (SLM) process is employed in high-precision layer-by-layer Additive Manufacturing (AM) on powder bed and aims to fabricate high-quality structural components. To gain a comprehensive understanding of the process and its optimization, both modeling and simulation in conjunction with extensive experimental studies along with laser calibration studies have been attempted. Multiscale and multi-physics-based simulations have the potential to bring out a new level of insight into the complex interaction of laser melting, solidification, and defect formation in the SLM parts. SLM process encompasses various physical phenomena during the formation of metal parts, starting with laser beam incidence and heat generation, heat transfer, melt/fluid flow, phase transition, and microstructure solidification. To effectively model this Multiphysics problem, it is imperative to consider different scales and compatible boundary conditions in the simulations. In this paper, we
Varma, AdityaGanesh, Kona VeeraRoy Mahapatra, Debiprosad
Testing aircraft antennas is challenging since optimal tests are made after antenna installation. Aircraft are often taken to anechoic antenna test facilities which create long lead times, transportation hassle, and very high costs. Portable alternatives exist but often have compromised testing fidelity. Innovators at the NASA Glenn Research Center have developed the PLGRM system, which allows an installed antenna to be characterized in an aircraft hangar. All PLGRM components can be packed onto pallets, shipped, and easily operated
Battery packs of electric vehicles are typically composed of lithium-ion batteries with aluminum and copper acting as cell terminals. These terminals are joined together in series by means of connector tabs to produce sufficient power and energy output. Such critical electrical and structural cell terminal connections involve several challenges when joining thin, highly reflective and dissimilar materials with widely differing thermo-mechanical properties. This may involve potential deformation during the joining process and the formation of brittle intermetallic compounds that reduce conductivity and deteriorate mechanical properties. Among various joining techniques, laser welding has demonstrated significant advantages, including the capability to produce joints with low electrical contact resistance and high mechanical strength, along with high precision required for delicate materials like aluminum and copper. The primary objective of this study was to join 0.8 mm thick aluminum
Ko, Byung MinGryguc, AndrewChen, JimHunt, JustinGuo, MingchaoZhang, WenshengJahed, HamidGerlich, Adrian
Ammonia has received attention as an alternative hydrogen carrier and a potential fuel for thermal propulsion systems with a lower carbon footprint. One strategy for high power density in ammonia applications will be direct injection of liquid ammonia. Understanding the evaporation and mixing processes associated with this is important for model development. Additionally, as a prior step for developing new injectors, it is of interest to understand how a conventional gasoline direct injection (GDI) injector would behave when used for liquid ammonia without any modifications. Pure anhydrous ammonia, in its liquid form, was injected from a single hole GDI injector at a fuel pressure of 150 bar into an optically accessible constant volume chamber filled with nitrogen gas for ammonia spray measurements. The chamber conditions spanned a wide range of pressures from 3 − 15 bar at an increment of 1 bar or 2 bar between the test points. These conditions lead to sprays which are both flash
Shen, LiLeach, Felix
Optical parametric oscillator (OPO) lasers test optical fibers and components to characterize the spectral response of optical components. OPO lasers are common in sophisticated test and measurement applications such as mass spectrometry, photoacoustic imaging, and spectroscopy. Now, these tunable pulsed lasers are being used to facilitate a range of tests at different wavelengths to qualify and quantify the performance of optical components such as fiber optic strands, filters, lenses, and coated mirrors
The process of manufacturing high-quality and reliable balloon catheters is critical to a number of advanced medical treatments for patients including balloon angioplasty, stent and drug delivery, transcatheter aortic valve implantation, atherectomy, renal denervation, and laser balloon angioplasty. These minimally invasive procedures have vastly improved quality of life, increased patient safety, decreased recovery times, and lowered treatment costs for patients around the globe
Light weight and Robust manufacturing technologies are always needed for transformation drive in the Automotive industry for the next-generation vehicles with greater Power to weight ratio. Innovations and process developments in materials and manufacturing processes are key to this light weighting transformation. Aluminium material has been widely used for these light weighting opportunities. However, aluminum joining techniques, characterized by their poor quality and consistency are limiting this transformation. This technical paper represents one of such case, where the part is made up of Aluminium through conventional casting route which has affected the laser weld quality due to poor casting soundness. This experiment explains in detail about the importance of Casting soundness for laser weld quality, weld penetration, strength etc., and the Product consistency. Casting soundness improvement explored with the support of Ingot quality, Die design, Gating design & Size, Overflow
Umasankar, MaiyarasanVenugopal, SivakumarGopalan, Vijaysankar
LiDAR stands for Light Detection and Ranging. It works on the principle of reflection of light. LiDAR is one among the other sensors like RADAR and Camera to help achieve a higher level (Level 3 & above) of Autonomous driving capabilities. LiDAR, as a sensor, is used to perceive the environment in 3D by calculating the ‘Time of flight’ of the Laser beam transmitted from LiDAR and the rays reflected from the Object, along with the intensity of reflection from the object. The frame of perception is plotted as a point cloud. LiDAR is integrated in front of the vehicle, precisely in the grill of the car having a high vantage point to perceive the environment to extract the best possible sensor performance. LiDAR sensor needs to be held within the front panel cutout with uniform gap and flush condition. However, due to tolerance reasons it may have following issues: Sensor functional degradation will happen if it is not aligned properly at the center to the cutout, because the view cones
Pratap, AmitRangarej, Sanjeev
High strength aluminium alloys are an ideal material in the automotive sector leading to a significant weight reduction and enhancement in product safety. In recent past extensive development in the field of high strength steel and aluminium was undertaken. This development has been propelled due to demand for light weight automotive parts. The high strength to weight ratio possessed by Al alloy helps in reducing the total weight of the vehicle without effecting the overall performance, thereby increasing the fuel economy, and reducing the carbon emission level. Joining of high strength aluminium alloy is critical to develop durable automotive products. Joining of high strength aluminium alloy for mass production in automobile industry is a challenging task. Laser welding is recognized as an advanced process to join materials with a laser beam of high-power, high- energy density. In the present study efforts are made to summarize the influence of important process parameters of laser
Sahu, HemantDave, RajeevChauhan, ShivDwivedi, Ravi
From monitoring concentrations of greenhouse gases to detecting COVID in breath, laser systems known as frequency combs can identify specific molecules as simple as carbon dioxide and as complex as monoclonal antibodies, with unprecedented accuracy and sensitivity. Amazing as they are, however, frequency combs have been limited in how fast they can capture a high-speed process such as hypersonic propulsion or the folding of proteins into their final three-dimensional shapes
Any plan for the long-term exploration or habitation of the Moon and Mars will almost certainly entail the use of multiple habitats, vehicles and remotely located equipment, all of which will require power sources
OPO lasers test optical fibers and components to characterize the spectral response of optical components, which can provide a competitive advantage in the optics industry
Positioning system is a key module of autonomous driving. As for LiDAR SLAM system, it faces great challenges in scenarios where there are repetitive and sparse features. Without loop closure or measurements from other sensors, odometry match errors or accumulated errors cannot be corrected. This paper proposes a construction method of LiDAR anchor constraints to improve the robustness of the SLAM system in the above challenging environment. We propose a robust anchor extraction method that adaptively extracts suitable cylindrical anchors in the environment, such as tree trunks, light poles, etc. Skewed tree trunks are detected by feature differences between laser lines. Boundary points on cylinders are removed to avoid misleading. After the appropriate anchors are detected, a factor graph-based anchor constraint construction method is designed. Where direct scans are made to anchor, direct constraints are constructed. While in the position where the anchor is not directly observed
Shen, XiangxiangLu, XiongZhu, JiaqiGao, LetianWu, JunxianLu, Yishi
Laser beams can be used to precisely measure an object’s position or velocity. Normally, however, a clear, unobstructed view of this object is required — and this prerequisite is not always satisfied. In biomedicine, for example, structures are examined that are embedded in an irregular, complicated environment. There, the laser beam is deflected, scattered, and refracted, often making it impossible to obtain useful data from the measurement
A team of University of Otago researchers and physicists have demonstrated a new form of antenna, developed with a small glass bulb containing an atomic vapor. The bulb was wired with laser beams and could therefore be placed far from any receiver electronics. Dr. Susi Otto, from the Dodd-Walls Centre for Photonic and Quantum Technologies, led the field testing of the portable atomic radio frequency sensor. Such sensors, that are enabled by atoms in a so-called Rydberg state, can provide superior performance over current antenna technologies as they are highly sensitive, have broad tunability, and small physical size, making them attractive for use in defense and communications
Teleo announced that Florida-based Tomahawk Construction will become the first customer to deploy its autonomous capabilities on an active jobsite. Starting in December, Tomahawk Construction's articulated dump trucks will use autonomous functions to move material to build a residential community in Naples, Florida. Teleo also announced deals with eight new construction customers, including Ajax Paving Industries in Florida. The new customers have placed orders for 42 machines to be retrofitted with Teleo's autonomous and remote-operated technology. In addition, the tech company expanded its global dealer partner network to include Ozark Laser, Murphy Tractor and Position Partners. The expanded network covers an additional seven states across the U.S. Midwest and in Australia
Gehm, Ryan
A team of University of Otago researchers and physicists have demonstrated a new form of antenna, developed with a small glass bulb containing an atomic vapor. The bulb was wired with laser beams and could therefore be placed far from any receiver electronics
While many artificial materials have advanced properties, they have a long way to go to combine the versatility and functionality of living materials that can adapt to their situation. Now, researchers from Imperial College London and University College London have demonstrated the first spontaneously self-organizing laser device, which can reconfigure when conditions change
Researchers from MIT Lincoln Laboratory and their collaborators at the Massachusetts General Hospital (MGH) Center for Ultrasound Research and Translation (CURT) have developed a new medical imaging device: the Noncontact Laser Ultrasound (NCLUS). This laser-based ultrasound system provides images of interior body features such as organs, fat, muscle, tendons, and blood vessels. The system also measures bone strength and may have the potential to track disease stages over time
Self-driving cars, like the human drivers that preceded them, need to see what’s around them to avoid obstacles and drive safely
Mass spectrometry (MS), which is used to identify molecules within a sample by measuring the mass-to-charge ratio of ions, is employed across many fields of study, including biology, chemistry, physics, and clinical medicine. As the technology continues to evolve, so will the applications that can benefit from this important tool
In this study, the authors analyze the concentration distribution of an evaporative spray mixture with LIEF (Laser induced exciplex fluorescence) method, which is a type of optical measurement. LIEF method is one of the optical measurements for obtaining the spray concentration distribution for separating vapor/liquid phases based on the fluorescence characteristics. In this paper, a quantitative concentration distribution analysis method for wall impingement spray in heterogeneous temperature field has been proposed. Then, a series of experiments were performed in varying injection pressure and ambient density. As a result, a two-dimensional concentration distribution was obtained for the free spray and wall impingement spray
Matsuda, DaiKimura, IppeiNishimura,, KanakoMatsumura, ErikoSenda, Jiro
The Euro 7 emission regulations currently under consideration by the EU will adopt on-road emissions test as the main Type Approval procedure, and it has been proposed that the number of gas components to be measured will be increased. Therefore, the Portable Emissions Measurement System (PEMS) used for on- road emissions testing must be able to simultaneously measure more components with higher precision while maintaining the same compact and lightweight structure as in the existing PEMS. The authors have applied a relatively new technique, quantum cascade laser infrared spectroscopy (QCL-IR), to an on-board multi-component gas analyzer. Comparison with laboratory tests on a gasoline passenger car on a dynamometer showed that the newly developed QCL- IR PEMS correlated well with conventional PEMS and stationary conventional analyzers. Signal noise and interference from other gases was also confirmed to show the expected performance, which was equal to or better than that of
Kondo, YosukeHamauchi, ShotaKowada, YoshihitoShibuya, KyojiOtsuki, Yoshinori
Heavy heat load is one of the bottlenecks restricting the highly intensive marine engine development. Reducing wall heat loss contributes to this target. The wall heat transfer is mainly influenced by flame-wall interaction (FWI). In this paper, a wall temperature distribution measurement system is developed based on the Laser-Induced Phosphorescence (LIP). The effects of the coating thickness and the laser fluence on LIP are studied to clarify the accuracy of wall temperature measurement based on LIP and the one-dimensional wall temperature distribution. In addition, a conjugate heat transfer model of FWI was established based on CONVERGE to simulate the FWI and the accompanying heat transfer process. The simulation is compared with the experimental wall temperature results and demonstrates the effectiveness of the conjugate heat transfer model. The influence of the initial velocity, the impinging distance and the wall roughness on the wall heat transfer are studied. The effective way
Xuefeng, XUERun, CHENTie, LIXinyi, ZHOUJiale, CAOXin, TANG
In a rapid compression and expansion machine (RCEM), spray flames from a two-hole injector are injected toward a wall to achieve jet-jet interaction after spray flames impinge onto the wall. Simultaneous laser-induced incandescence (LII) and laser scattering (LS) measurements were performed to investigate the soot formation process in the jet-jet interaction zone. The results showed that high LII and LS signals were detected in the interaction region and persisted for a considerable period and that soot particle size in the interaction zone was independent of the time and injection pressure
Horibe, NaotoInoue, DaichiAoyagi, ShinnosukeHayashi, JunKawanabe, Hiroshi
A set of power measurements as a function of controlled nanopositioner movement of a planar film arrangement in a standing wave field is presented as a means to obtain the thicknesses and the dielectric constants to a precision dictated by noise in an exciting laser beam and the positioning and detector process, all of which can be refined with averaging. Purdue University, West Lafayette, IN The broad need for determining the optical properties of thin films in a multitude of applications is usually served by ellipsometry. Practical application of ellipsometry generally requires prior constraints, typically in the form of a frequency-dependent model. To provide for a suitable solution of the inverse problem, where film parameters are determined from a set of optical measurements. We present motion in structured illumination as a means to obtain additional information and hence avoid the need for a material response model. Using this approach, inversion for multiple parameters at each
Rensselaer Polytechnic Institute’s Moussa N’Gom has devised a method to make communications between satellites and the ground more effective — regardless of the weather. N’Gom and his team used ultrafast, femtosecond lasers to cut through the clouds and rain that commonly cause losses in free-space optical communication (FSO
In an application first, the physics of why the sky is blue is used to measure gas flows without obstructive sensors. A longstanding industry partnership between Virginia Polytechnic Institute and State University (Virginia Tech) and Pratt & Whitney has resulted in a new laser-optical technology that aims to revolutionize in-flight thrust measurement
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