Profile & Process
Robert Valdiviez, PE is the President and Chief Engineer of Applied Mechanics Engineering, LLP, which was formed in 2019. Robert has over forty years of experience in mechanical engineering design, analysis, testing, evaluation, and management. His work spans the industries of energy, defense, aerospace, and general industrial applications of mechanical systems. This diverse work experience provides Robert with an experienced technical perspective for effectively evaluating a mechanical system or device operating within its functional environment.
The aim of the process is to provide to the client a quantified assessment of how their system or component functions in the environment of interest. At the core of this process is engineering simulation, where an analytical model of the system or component is created, and used to provide quantified response predictions. The engineering simulation effort, coupled with an effective testing program will reveal true physical functioning, and allow for a detailed understanding of the performance of the system or component.
Consultation
Robert is available to conduct a no-cost initial consultation process with a potential client about a particular equipment application. Meetings and/or information exchanges will be used as needed. The goal is to ensure that a potential client and Applied Mechanics Engineering are in complete agreement on the scope, content, and deliverables of the work before any contractual agreement is signed. Various communication methods can be employed to accomplish the initial consultation.
Sampling of Past Relevant Work
(Additional Project Work is Presented on the Experience Page)
2-D Model of the Confinement Vessel (Structural FEA model and Hydrodynamic Code prediction of the shock front overlaid)
structural dynamics
Confinement Vessel Loading Due to Internal High Explosive Charge Detonation
This application involves the design and analysis of a simple cylindrical, thick-walled vessel that is used to safely confine the detonation products of 34 grams of a high explosive being detonated inside of the vessel. The vessel is specifically designed for impulsive loading, and is a vehicle for performing small shock physics experiments. The detonation event is interrogated through the vessel wall using various diagnostic techniques.
The vessel is designed per the ASME Boiler and Pressure Vessel code requirements, Section VIII, Division 3, Code Case 2564. This code case provides the design requirements to be met for impulsively loaded vessels, such as this one undergoing interior explosive blast loading. The fabricated vessel is not a code stamped vessel due primarily to the materials of construction used not being code listed materials.
The vessel has a wall thickness of 0.59 inch, is 9.56 inches in inside diameter, 13.7 inches in inside length, and weighs approximately 430 pounds when fully outfitted for an experiment.
For detailed information of this application please see ASME Pressure Vessels & Piping Division conference paper PVP2011-57129, or Los Alamos National Laboratory publication LA-UR-11-02051.
Charged particle beam interceptive device, or scraper, shown in solid view, and with the predicted peak temperatures contour.
heat transfer and Fluid flow
Heat Transfer and Coolant Flow Design of an Interceptive Device for Charged Particle Beam Measurements
This application covers the design and analysis of a device that is used to intercept a charged particle beam (H+ beam) to search for beam profile anomalies. The face of the interceptive device, or scraper, is made of graphite, with a copper backing and base to allow for an effective heat removal path. The thermal response of the scraper in the short term is such that a small portion of the graphite face rises in temperature considerably while intercepting the very small spot size pulsed beam, to a peak temperature of approximately 920 degrees Fahrenheit (493 degrees Celsius). The graphite face protects the underlying copper component. The copper component base and the water circular cooling channel serve to remove the thermal power over a longer time scale than the beam to face interaction.
Included in the design, analysis, and testing scope of work was the stable structural support of the instrument for minimizing motion due to the coolant flow (flow induced vibration). The sensing portion of the scraper could not experience excessive motion during beam profile measurements being taken.
The scraper sensing area is approximately 1.0 inch by 1.0 inch by 0.3 inch thick. The coolant channel in the copper base is approximately 0.2 inch in inside diameter.
For detailed information of this application please see ASME Heat Transfer Division conference paper NHTC01-1521, or Los Alamos National Laboratory publication LA-UR-01-2915.
Above image shows the rocket engine nozzle interfacing with the diffuser inlet, lower image shows the diffuser coupled to a turning elbow, and the elbow connected to a tube bank in shell style heat exchanger.
heat transfer and Fluid flow
Thermal-Hydraulic Design and Analysis for Aerospace Ground Test Equipment
This application involves the design and analysis of a diffuser and heat exchanger set for receiving the supersonic high-temperature gas flow exiting a rocket engine under test. The diffuser allows primarily for the deceleration of the flow, and the heat exchanger primarily cools the gas flow prior to the flow entering down stream components of the test facility. The engine test stand, water cooled diffuser, turning elbow, and heat exchanger are all located within a large atmospheric chamber, and are connected to the facility evacuation system where the engine propellant reaction gasses are drawn out of the system and exhausted to the atmosphere. The absolute pressure within the atmospheric chamber can be maintained as low as approximately 1 Torr, and can rise during the actual engine firing to a few tens of Torr, depending on the nozzle insertion depth and angle in the diffuser entry, and the engine propellant flow rate.
Included in the scope of work was the design for the static and dynamic support of the large components within the testing atmospheric chamber.
The diffuser inside diameter is approximately 17 inches, is approximately 115 inches in length, and weighs approximately 3,810 pounds before any water filling.
For detailed information of this application please see the American Institute of Aeronautics and Astronautics 1996 Lake Buena Vista, FL USA Joint Propulsion conference paper titled “Cassini Main Engine Assembly Testing”.