18 Aug 2023

Unmanned Ground Vehicle (UGV) Path Planning in 2.5D and 3D

Abstract: Herein, we explored path planning in 2.5D and 3D for unmanned ground vehicle (UGV) applications. For real-time 2.5D navigation, we investigated generating 2.5D occupancy grids using either elevation or traversability to determine path costs. Compared to elevation, traversability, which used a layered approach generated from surface normals, was more robust for the tested environments. A layered approached was also used for 3D path planning. While it was possible to use the 3D approach in real time, the time required to generate 3D meshes meant that the only way to effectively path plan was to use a preexisting point cloud environment. As a result, we explored generating 3D meshes from a variety of sources, including handheld sensors, UGVs, UAVs, and aerial lidar.

17 Aug 2023

A/E/C Graphics Standard: Release 2.2

Abstract: The A/E/C Graphics Standard Release 2.2 has been developed by the Computer-Aided Design/Building Information Modeling Technology Center to document how proper hand-drafting practices can be achieved in advanced modeling. It is through the collection and documentation of these practices that consistent models and drawings shall be achieved throughout the US Army Corps of Engineers (USACE), as well as other federal agencies. In the collection of these practices, various historical USACE District drafting manuals were consulted and compared against practices contained in industry and national standards, with consideration toward whether software can achieve those practices. The documentation of these practices will help to achieve both clear and aesthetically pleasing construction documents.

9 Aug 2023

Repair of Corroded Steel Girders of Hydraulic Steel Structures (HSS) Using Fiber-Reinforced Polymers (FRP)

Abstract: Although steel hydraulic structures have a protective system to prevent corrosion, this type of deterioration will eventually occur due to the constant exposure to harsh environmental conditions. There are several techniques that can be implemented to repair corroded steel structural elements. This report presents a numerical study to evaluate the mechanical behavior of corroded steel girders used in hydraulic steel structures and to evaluate several carbon fiber–reinforced polymers (CFRP) layups to repair them. The girders were modeled as simply supported with four-point loading boundary conditions. The corrosion deterioration was modeled as loss in section as 10%, 25%, and 40%. The effectiveness of the deterioration was established based on the level of stresses at the steel compared with the undamaged condition after it is strengthened with CFRP. It was found that CFRP repair is more practical for reducing the stresses at the steel in the shear dominated zone if deterioration is below 25%. At the tensile dominated zone, CFRP is effective for reducing the stresses for deterioration below 40%.

19 Jul 2023

Adverse Outcome Pathways for Engineered Systems

Abstract: Companies and organizations around the world spend massive amounts of money each year to discover, predict, and remediate failures within engineered systems. These tasks require individuals with specialized knowledge in a variety of topics related to failure. This knowledge is often acquired through years of academic and on-the-job training centered around the review of scientific documentation such as books, reports, manuals, and peer-reviewed publications. The loss of this knowledge through employee attrition can be detrimental to a group as knowledge is often difficult to reacquire. The aggregation and representation of known failure mechanisms for engineered materials could aid in the sharing of knowledge, the acquisition of knowledge, and the discovery of failure causes, reducing the risk of failure. Thus, the current work proposes the Adverse Outcome Pathway for Engineered Systems (AOP-ES) framework, an extension of the Adverse Outcome Pathway used in toxicology. The AOP-ES is designed to document failure knowledge, enabling knowledge transfer and the prediction of failures of novel engineered materials based on the performance of similar materials. This paper introduces the AOP-ES framework and its key elements alongside the principles that govern the framework. An application of the framework is presented, and additional benefits are explored.

6 Jul 2023

A General-Purpose Multiplatform GPU-Accelerated Ray Tracing API

Abstract: Real-time ray tracing is an important tool in computational research. Among other things, it is used to model sensors for autonomous vehicle simulation, efficiently simulate radiative energy propagation, and create effective data visualizations. However, raytracing libraries currently offered for GPU platforms have a high level of complexity to facilitate the detailed configuration needed by gaming engines and high-fidelity renderers. A researcher wishing to take advantage of the performance gains offered by the GPU for simple ray casting routines would need to learn how to use these ray tracing libraries. Additionally, they would have to adapt this code to each GPU platform they run on. Therefore, a C++ API has been developed that exposes simple ray casting endpoints that are implemented in GPU-specific code for several contemporary device platforms. This API currently supports the NVIDIA OptiX ray tracing library, Vulkan, AMD Radeon Rays, and even Intel Embree. Benchmarking tests using this API provide insight to help users determine the optimal backend library to select for their ray tracing needs. HPC research will be well-served by the ability to perform general purpose raytracing on the increasing amount of graphics and machine learning nodes offered by the DoD High Performance Computing Modernization Program.

22 May 2023

Advances in Dredged Material Evaluations for Inland and Ocean Aquatic Placement: Modernized Processes and Supportive Tools

Abstract: As part of the US Army Corps of Engineers’ mission to evaluate and move dredged material (DM) to maintain navigation channels, environmental evaluation of the prospective material is required by the Code of Federal Regulations. While existing guidance manuals provide useful guidance to DM regulators, they are over 30 years old and not reflective of the latest science. However, efforts to update procedures and publish the documents individually or as a combined dredging manual have been thus far unsuccessful. These issues, coupled with a lack of consistent reporting and decision documentation, lead to delays arising from challenges addressing project-specific issues not clearly covered within the existing guidance, revisiting previously resolved issues or negotiating disputes between permitting authorities. This technical report provides a path toward modernization of the environmental compliance aspects of DM evaluation guidance in part through software executables guiding the management and decision process and through a structured, evidence-based approach. The value added is an updated approach to DM testing and evaluation decisions.

21 Apr 2023

Early Life-Cycle Prediction of Reliability

Abstract: The intent of this project is to investigate a variety of approaches for the development of a basic model for the early life-cycle prediction of reliability (pre-Milestone A). The United States Department of Defense (DoD) currently utilizes an acquisition framework in which system development advances through a series of checkpoints known as milestones. Each milestone represents a decision point, with Milestone A being the earliest in the life cycle. At Milestone A, also known as the risk-reduction decision, the DoD evaluates design concepts while also committing funds to the maturation of technologies in an effort to mitigate future risks. Typically, little is known about the particular system to be developed at this point in the acquisition life cycle, but DoD regulations require program man-agers to submit system reliability information (OUSD[A&S] 2015). Traditional reliability predictions, however, require extensive knowledge of the system of interest to produce accurate results. This level of knowledge is unavailable at or before Milestone A, there-fore, there is a need to create models and methodologies for the prediction of system reliability. This report provides an overview of a variety of methods investigated to improve the prediction of early life cycle reliability.

23 Mar 2023

Experimental Fatigue Evaluation of Underwater Steel Panels Retrofitted with Fiber Polymers

Abstract: Many steel structures are susceptible to fatigue loading and damage that potentially threaten their integrity. Steel hydraulic structures (SHS) experience fatigue loading during operation and exposure to harsh environmental conditions that can further reduce fatigue life through stress corrosion cracking and corrosion fatigue, for example. Dewatering to complete inspections or repairs to SHS is time consuming and leads to economic losses, and current repair methods, such as rewelding, often cause new cracks to form after relatively few cycles, requiring repeated inspection and repair. The use of bonded carbon fiber–reinforced polymer (CFRP) to repair fatigue cracks in metallic structures has been successful in other industries; recent work suggests that this method offers a more reliable repair method for SHS. Studies regarding CFRP retrofits of SHS indicate that early bond failure often controls the degree of fatigue life extension provided by the repair. This study aims to extend previous studies and increase the fatigue life of repaired steel components by employing methods to improve CFRP bonding. Additionally, using basalt reinforced polymer (BFRP) instead of CFRP is proposed. BFRP is attractive for SHS because it does not react galvanically and has excellent resistance to chemically active environments.

21 Mar 2023

An Ontology for an Epigenetics Approach to Prognostics and Health Management

Abstract: Techniques in prognostics and health management have advanced considerably in the last few decades, enabled by breakthroughs in computational methods and supporting technologies. These predictive models, whether data-driven or physics-based, target the modeling of a system’s aggregate performance. As such, they generalize assumptions about the modelled system’s components, and are thus limited in their ability to represent individual components and the dynamic environmental factors that affect composite system health. To address this deficiency, we have developed an epigenetics-inspired knowledge representation for engineered system state that encompasses components and environmental factors. Epigenetics is concerned with explaining how environmental factors affect the expression of an organism’s genetic material. The field has derived important insights into the development and progression of disease states based on how environmental factors impact genetic material, causing variations in how a gene is expressed. The health of an engineered system is similarly influenced by its environment. A foundation for a new approach to prognostics based on epigenetics must begin by representing the entities and relationships of an engineered system from the perspective of epigenetics. This paper presents an ontology for an epigenetics-inspired representation of an engineered system. An ontology describing the epigenetics of an engineered system will enable the composition of a formal model and the incremental development of a more robust, causal reasoning system.

22 Dec 2022

2021 Guided Wave Inspection of California Department of Water Resources Tainter Gate Post-Tensioned Trunnion Anchor Rods: Oroville Dam

Abstract: The Engineering and Test Branch within the Division of Operations and Maintenance of the California Department of Water Resources (DWR) and U.S. Army Corps of Engineers (USACE), Sacramento District, tasked the Sensor Integration Branch (SIB) at the Engineer Research and Development Center (ERDC) to perform nondestructive testing (NDT) on the trunnion anchor rods at Oroville Dam through the use of ultrasonic guided waves. This is the fourth year of this NDT. The results of the testing are presented along with qualitative analysis in determining whether a rod is intact or compromised. Analysis is based upon the expected results from other rods at the site, knowledge of rod response at other sites, data gathered from the trunnion rod research test bed at ERDC, and comparison to the previous year’s effort.