Browse Topic: Soils
ABSTRACT When building simulation models of military vehicles for mobility analysis over deformable terrain, the powertrain details are often ignored. This is of interest for electric and hybrid-electric vehicles where the maximum torque is produced at low speeds. It is easy to end up with the drive wheels spinning and reducing traction and eventually the vehicle digging itself down in the soil. This paper reveals improvements to mobility results using Traction Control Systems for both wheeled and tracked vehicles. Simulations are performed on hard ground and two types of deformable soil, Lethe sand and snow. For each soft soil, simulations have been performed with a simple terramechanics model (ST) based on Bekker-Wong models and complex terramechanics (CT) using the EDEM discrete element soil model which Pratt & Miller Engineering (PME) has been instrumental in developing. To model the traction control system a PD controller is used that tries to limit the slip velocity at low speed
ABSTRACT The NATO Reference Mobility Model (NRMM) is an empirically based tool developed to facilitate comparisons between vehicle design candidates and to assess their mobility under specific mission profiles. It was originally established in the 1960s and 1970s, during a time when modern computational methods were in their infancy. Since its initial development, the NRMM has been revised and updated several times, but there has always been a deficiency – a thorough understanding of the vehicle capabilities for each mission profile. With the advent of modern simulation tools, coupled with the latest in data visualization and analytics, a new generation of mobility models may be built that cannot only assess a vehicle’s mobility, but also understand its extended range in various soil types, and more specific terrains or operational conditions. This presentation will discuss the capabilities of advanced simulation and visualization software and their ability to affect how mission
ABSTRACT Researchers at Caterpillar have been using Finite Element Analysis or Method (FEA or FEM), Mesh Free Models (MFM) and Discrete Element Models (DEM) extensively to model different earthmoving operations. Multi-body dynamics models using both flexible and rigid body have been used to model the machine dynamics. The proper soil and machine models along with the operator model can be coupled to numerically model an earthmoving operation. The soil – machine interaction phenomenon has been a challenging matter for many researchers. Different approaches, such as FEA, MFM and DEM are available nowadays to model the dynamic soil behavior; each of these approaches has its own limitations and applications. To apply FEA, MFM or DEM for analyzing earthmoving operations the model must reproduce the mechanical behavior of the granular material. In practice this macro level mechanical behavior is not achieved by modeling the exact physics of the microfabric structure but rather by
ABSTRACT In 2014, a NATO Applied Vehicle Technology (AVT) Exploratory Team 148 (ET-148) was formed to explore the development of an improved Next-Generation NATO Reference Mobility Model (NG-NRMM)[1]. A development path forward was identified and initiated in a subsequent NATO research task group (AVT-248) to implement ET-148 recommendations. One key area for improvement was the vehicle-terrain interaction (Terramechanics) models defining important performance metrics for off-road performance in differing soils, and environmental conditions. The near term implementation focuses on existing “Simple” Terramechanics models as a practical improvement to the incumbent NRMM Cone Index (CI) empirically based method, without requiring the computational power of the large scale complex discrete element model (DEM) methods that are the targeted long term solution. Practical approaches and limitations to the implementation of these existing Simple Terramechanics models in 3D vehicle models are
Designing non-destructive test (NDT) systems for aerospace clients can feel like engineering with blindfolds on. Even when the parts under test aren’t confidential, they can change rapidly as companies optimize their designs. This accelerated innovation helps launch more powerful, safer vehicles for use inside Earth’s orbit and beyond. But how do you create precision inspection systems without knowing what they’ll inspect in the field
A new robotic suction cup which can grasp rough, curved, and heavy stone, has been developed by scientists at the University of Bristol. The team, based at Bristol Robotics Laboratory, studied the structures of octopus biological suckers, which have superb adaptive suction abilities enabling them to anchor to rock
The manufacturing landscape is undergoing a transformation, propelled by the need for innovative, efficient, and precise technology that can effectively replace expensive manual labor. This article examines advancements in Flexiv’s material abrasion technology, specifically focusing on sanding and polishing applications and the utility of force control technology
Lunar landing and launch pads represent critical infrastructure for enabling a sustained presence on the Moon or other planetary bodies. Such a Moon presence would require repeated lunar landings and takeoffs, preferably near an outpost or habitat. In the absence of takeoff and landing pads, such vehicles could project lunar regolith at high velocities, sandblasting the surrounding infrastructure and causing damage
Storing energy is one of the key challenges for implementing sustainable but intermittent electricity sources like solar and wind. Engineers at Sandia National Laboratories are collaborating with New Mexico-based CSolPower LLC to develop a very affordable method of accomplishing that storage
When asked about the most dreaded tasks on the manufacturing floor, many teams point to sanding, grinding, or polishing. These unforgiving tasks can be tedious, time-consuming, and hazardous, leading to respiratory illnesses and repetitive motion injuries. In today’s economic climate, finding workers willing to perform these taxing jobs can be challenging. Yet, they are often necessary when assembling metal, composite, or other parts into manufactured products
In Penn’s Clean Energy Conversions Lab, researcher Peter Psarras and colleagues are repurposing waste from industrial mines, storing carbon pulled from the atmosphere into newly formed rock. The team sees great environmental potential in mine tailings, the sand and sludge left behind after the sought-after ore gets removed. With samples in the lab, they’re trying to determine just how much calcium and magnesium each contains, how to best carbonate it with CO2, how and where they can store the result, and whether the process is scalable
Litter is not only a problem on Earth. According to NASA, there are currently millions of pieces of space junk in the range of altitudes from 200 to 2000 kilometers above the Earth’s surface, which is known as low-Earth orbit (LEO). Most of the junk is comprised of objects created by humans, like pieces of old spacecraft or defunct satellites. This space debris can reach speeds of up to 18,000 miles per hour, posing a major danger to the 2612 satellites that currently operate at LEO. Without effective tools for tracking space debris, parts of LEO may even become too hazardous for satellites
A team at Delft University of Technology has built a new technology on a microchip by combining two Nobel Prize-winning techniques for the first time. This microchip could measure distances in materials at high precision — e.g., underwater or for medical imaging. The work is now published in Nature Communications. Because the technology uses sound vibrations instead of light, it is useful for high-precision position measurements in opaque materials. The instrument could lead to new techniques to monitor the Earth’s climate and human health
Exploring and developing permanent infrastructure on Mars requires the development of technologies to enable safe and efficient operations, from landing, roving, and extravehicular activities (EVAs) to prospecting, evaluating, acquiring, extracting, and utilizing local resources. Martian regolith is likely to be the main resource used for initial Martian in situ resource utilization (ISRU) to lessen the amount of resources and supplies that must be launched at high cost from Earth and take up precious cargo space
Scientists have uncovered how heavy, motorized objects climb steep slopes — a newly discovered mechanism that also mimics how rock climbers navigate inclines. The finding stems from a series of experiments in which motorized objects were placed in liquid and then moved up tilted surfaces. These “micro-swimmers” are about 20 times heavier than the fluid they swim in but they were able to climb almost vertical steep slopes
Researchers from MIT’s Improbable Artificial Intelligence Lab, part of the Computer Science and Artificial Intelligence Laboratory (CSAIL), have developed a legged robotic system that can dribble a soccer ball under the same conditions as humans. The bot used a mixture of onboard sensing and computing to traverse different natural terrains such as sand, gravel, mud, and snow, and adapt to their varied impact on the ball’s motion. Like every committed athlete, “DribbleBot” could get up and recover the ball after falling
The analysis of lipid biomarkers has gained increasing importance within environmental and archaeological fields because biomarkers are representative of plant and animal sources. Proven gold standard laboratory techniques for lipid biomarker extraction are laborious, with many opportunities for human error. As a solution, NASA Ames Research Center has developed a novel technology that provides an autonomous, miniaturized fluidic system for lipid analysis. The technology, in a single instrument, can accept an unprocessed soil, rock, or ice sample, comminute the sample, extract lipids via sonication and blending, filter out mineral residue, concentrate the analyte, and deliver the aliquot to downstream analytical instruments for molecular characterization, without requiring intervention from a human operator
A team of researchers at University of California, Riverside, has moved a step closer to finding a use for the hundreds of millions of tons of plastic waste produced every year that often winds up clogging streams and rivers and polluting our oceans
“This is the equivalent of having a wearable health sensor on your body that tells you in real-time what’s happening. Think of it as a wearable for the soil,” said Dr. Shalini Prasad. “We are excited about the potential for our soil sensors to provide more accurate testing of living soil in its ecosystem
Ionospheric variability is a critical consideration for communication systems, GNSS, and space asset management. At high magnetic latitudes, the convergent magnetic field acts as a lens, focusing electromagnetic power originating from solar wind-magnetosphere interactions into a limited latitudinal range. The geometry and ensuing complex coupling processes result in extreme multi-scale time-dependent variations in the structure and composition of the ionized gases in Earth’s outer atmosphere. Understanding the mechanisms and technological consequences of these interactions benefits from distributed heterogeneous time-dependent measurements of the ionosphere-thermosphere-magnetosphere system, and their application as constraints on predictive space weather models
The oceans make up 71 percent of Earth’s surface and absorb about 30 percent of the carbon dioxide (CO2) that is released into the atmosphere. For the past 2.6 billion years, the oceans have been converting CO2 to ocean fish food (phytoplankton) through the process of photosynthesis. Now, a technology developed by Ocean-Based Climate Solutions, a startup located in Santa Fe, NM, is converting CO2 to phytoplankton using wave energy
Scientists at NASA’s Langley Research Center have developed a novel concept for a lunar navigation system based on the reverse-ephemeris technique. Typically, range-related signal measurements from the Earth’s surface are used to locate and track orbital objects (satellites) and establish the ephemeris describing their orbits. For this reverse-ephemeris lunar navigation concept, the process is reversed to give lunar surface position fixes using the known ephemeris of a satellite in lunar orbit
To make sure our buildings and infrastructure are earthquake-safe, we must understand how seismic activity affects different structures. Two major research efforts funded by the Department of Energy (DOE) seek to fill in the gaps and provide resources for researchers and engineers to study earthquakes across scales, from the initiation of seismic waves at the fault rupture site deep underground, to the interactions between shaking soil and individual structures at the surface
A small amount of simulated crushed Martian rock mixed with a titanium alloy made a stronger, high-performance material in a 3D-printing process that one day could be used on Mars to make tools or rocket parts. The parts were made by Washington State University researchers with as little as 5 percent up to 100 percent Martian regolith, a black powdery substance meant to mimic the rocky, inorganic material found on the surface of Mars
Spaceborne Synthetic Aperture Radar (SAR) can globally monitor dynamic processes on the Earth’s Surface. The last SAR to be developed and deployed by NASA was in the year 2000. This system’s high costs inhibited development of new and improved designs. NASA has now developed a new, state-of-the-art SAR system that can provide capabilities beyond established systems and at a fraction of the cost
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