ROV Design for Pluvial Applications

Date Received: November 7th, 2012 Fecha de recepción: 7 de Noviembre de 2012 Date Accepted: February 7th, 2013 Fecha de aceptación: 7 de Febrero de 2013 ROV Design for Pluvial Applications 1 Mechanical Department Federal University of Rio de Janeiro, Rio de Janeiro Brazil. e-mail: krloslozano@ufrj.br 2 Mechanical Department Federal University of Rio de Janeiro, Rio de Janeiro Brazil. e-mail: max@coppe.ufrj.br Ship Science & Technology Vol. 8 n.° 15 (69-74) July 2014 Cartagena (Colombia) 70 Floods represent a big problem in the Brazilian south and south-east regions. Due to unplanned occupation of river lands, the Brazilian populations must endure $oods and mudslides [1, 2]. Furthermore, human, environmental, and material damage changes the region’s vulnerability. "e level of soil on river beds is a variable that can be used to measure the degree of danger areas near rivers, given that this is dependent on the amount of water that the bed has in a speci!ed interval of time. "e autonomous vehicle [3-7], object of this project, consists of a system that provides monitoring of river beds compare to [8, 9], through the detection of signi!cant changes in ground levels, as done in [8, 10, 11]; also, with data transmission over wireless networks. Based on the technology of embedded systems, the autonomous vehicle will also get information related to physical and chemical conditions of the water (temperature, density, salinity, pH, and other variables) [12, 13]. "e vehicle will also have the functionality of remote handling when the system detects any abnormalities or changes in the environment and the solution depends on human intervention [9]. "erefore, a communication interface is established based on wireless networks (IEEE 802.11), optical networks and/or sensor network (IEEE 802.15.4E) and mesh networks. "is interface will provide greater $exibility to the autonomous vehicle, facilitating its con!guration and operation in areas of di#cult access [12, 14]. Future modi!cations will be included (the projection of a decision center, oriented environmental monitoring), which will add value to the project to process the information perceived by the autonomous vehicle and use of disaster prevention. "is work will be present a proposal for a mechanical structure that will be used as a prototype for future developments. For the present application, Solid-Works software was used, along with analysis tools through !nite elements. Two materials were tested: 2024-T4 (ASME) aluminum alloy and L316 alloy steel (AISI). Further, we used two structures of di%erent dimensions to validate di%erent behaviors. "e !rst material used was the aluminum alloy known as aeronautical construction material (2024T4), whose composition includes: Al: 90.7%, Cr: 0.1%, Cu: 4.9%, Fe: 0.5%, Mg: 1.8%, Mn: 0.9%, Si: 0.5%, Ti: 0.15%, Zn: 0.25%. Aluminum alloys are well known in di%erent applications for their properties for machinability and surface !nish, with high strength and adequate workability. "ey are used in structural applications, like, aircraft !ttings, fuse parts, hydraulic valve bodies, piston recti!er parts, worm gears, fastening devices; in this application aluminum was used because the environment where the robot will operate presents high pressure and corrosion conditions due to the depth and chemical components of the water. "e second material used was 316-L stainless steel; the characteristics for this material include good cold formability and high strain hardening capacity. Generally, it is not magnetic, but may have small amounts of ferrite; thereby, presenting mild magnetism. When cold-deformed, it becomes partially martensitic and lightly magnetic. It is very ductile. Machinability is considered bad except for steels and resulfurized CORFaC. Corrosion resistance: shows high resistance means in acetic acid, sulfuric 1% picric, nitric, oleic acid, formic acid, boric acid, benzoic acid and chromic at 20 °C. Good resistance means in concentrated acetic acid at 70 °C, citric acid, 10% oxalic acid, phosphoric acid at 100 °C, 5% sulfuric acid at 20 °C. Saline solutions: chlorides of magnesium, calcium, zinc, potassium permanganate, potassium sulfate at 20 °C, nitrate, cyanide and copper acetate. Applications in sea water: good resistance at 20 °C. Water: good resistance at any temperature. Introduction Materials and Methods Material Properties Lozano, Dutra Ship Science & Technology Vol. 8 n.° 15 (69-74) July 2014 Cartagena (Colombia) 71 For the structure, a tubular pro! le was used with two di% erent diameters, which will from now on be known as minor-car (MC) and normal-car (NC). " e MC has an external diameter of 0.03 m and internal wall of 0.005 m; the NC has an external diameter of 0.05 m and internal wall of 0.01 m. For NC, the principal volumetric properties for both materials were obtained, shown on Table 1. Also, for MC, the principal volumetric properties for both materials were obtained, shown on Table 2. Structure Material Type of design Focus / Framework Aluminum 2024-T4 Mass: 38.1723 kg Volume: 0.0137311 m3 Density: 2780 kg/ m3 Weight: 374.089 N Stainless Steel 316-L Mass: 109.848 kg Volume: 0.0137311 m3 Density: 8000 kg/ m3 Weight: 1076.52 N Material Type of design Focus / Framework Aluminum 2024-T4 Mass: 9.52268 kg Volum: 0.00342542 m3 Density: 2780 kg/ m3 Weight: 93.3223 N Stainless Steel 316-L Mass: 27.4034 kg Volume: 0.00342542 m3 Density: 8000 kg/ m3 Weight: 268.553 N ROV Design for Pluvial Applications Ship Science & Technology Vol. 8 n.° 15 (69-74) July 2014 Cartagena (Colombia) 72 Both of structures were tested with the same applied forces (78.5 N + 38.5 N); forces represent the maximum forces due to the four thrusters propulsion, and the second force is relative to the force that a generator will add to the structure. And pressures (2.354.400 N/m^2) come from the maximum application of the robot in the extreme river depth observed, which is 240 m. " e structure was also ! xed on two components representing the ground connection between the car and the soil of the water. " is work tested four models (two for each material NC and MC); each model with the same conditions represents di% erent behaviors, as expected. Results for aluminum in NC and MC are presented for both of the structures; furthermore, the results obtained for the steel alloy will be presented. Both structures were tested and analyzed in two ways, tensile analysis (Tables 3 and 4) and safety factor analysis (Tables 5 and 6). " ey were obtained from Von Misses theorem; these results were calculated with Solid Works tools through ! nite element analysis. Results Table 4. Tensile analysis in Stainless Steel alloy Material Type of design Focus / Framework Aluminum 2024-T4 Normal Car Min: 134906

Floods represent a big problem in the Brazilian south and south-east regions.Due to unplanned occupation of river lands, the Brazilian populations must endure oods and mudslides [1,2].Furthermore, human, environmental, and material damage changes the region's vulnerability.
e level of soil on river beds is a variable that can be used to measure the degree of danger areas near rivers, given that this is dependent on the amount of water that the bed has in a speci ed interval of time.
e autonomous vehicle [3][4][5][6][7], object of this project, consists of a system that provides monitoring of river beds compare to [8,9], through the detection of signi cant changes in ground levels, as done in [8,10,11]; also, with data transmission over wireless networks.Based on the technology of embedded systems, the autonomous vehicle will also get information related to physical and chemical conditions of the water (temperature, density, salinity, pH, and other variables) [12,13].
e vehicle will also have the functionality of remote handling when the system detects any abnormalities or changes in the environment and the solution depends on human intervention [9].erefore, a communication interface is established based on wireless networks (IEEE 802.11), optical networks and/or sensor network (IEEE 802.15.4E) and mesh networks.is interface will provide greater exibility to the autonomous vehicle, facilitating its con guration and operation in areas of di cult access [12,14].
Future modi cations will be included (the projection of a decision center, oriented environmental monitoring), which will add value to the project to process the information perceived by the autonomous vehicle and use of disaster prevention. is work will be present a proposal for a mechanical structure that will be used as a prototype for future developments.
For the present application, Solid-Works software was used, along with analysis tools through nite elements.Two materials were tested: 2024-T4 (ASME) aluminum alloy and L316 alloy steel (AISI).Further, we used two structures of di erent dimensions to validate di erent behaviors.e rst material used was the aluminum alloy known as aeronautical construction material (2024-T4), whose composition includes: Al: 90.7%, Cr: 0.1%, Cu: 4.9%, Fe: 0.5%, Mg: 1.8%, Mn: 0.9%, Si: 0.5%, Ti: 0.15%, Zn: 0.25%.Aluminum alloys are well known in di erent applications for their properties for machinability and surface nish, with high strength and adequate workability.ey are used in structural applications, like, aircraft ttings, fuse parts, hydraulic valve bodies, piston recti er parts, worm gears, fastening devices; in this application aluminum was used because the environment where the robot will operate presents high pressure and corrosion conditions due to the depth and chemical components of the water.e second material used was 316-L stainless steel; the characteristics for this material include good cold formability and high strain hardening capacity.Generally, it is not magnetic, but may have small amounts of ferrite; thereby, presenting mild magnetism.When cold-deformed, it becomes partially martensitic and lightly magnetic.It is very ductile.Machinability is considered bad except for steels and resulfurized CORFaC.Corrosion resistance: shows high resistance means in acetic acid, sulfuric 1% picric, nitric, oleic acid, formic For the structure, a tubular pro le was used with two di erent diameters, which will from now on be known as minor-car (MC) and normal-car (NC).e MC has an external diameter of 0.03 m and internal wall of 0.005 m; the NC has an external diameter of 0.05 m and internal wall of 0.01 m.

Material Properties
For NC, the principal volumetric properties for both materials were obtained, shown on Table 1.Also, for MC, the principal volumetric properties for both materials were obtained, shown on Table 2.

Structure
Both of structures were tested with the same applied forces (78.5 N + 38.5 N); forces represent the maximum forces due to the four thrusters propulsion, and the second force is relative to the force that a generator will add to the structure.And pressures (2.354.400N/m^2) come from the maximum application of the robot in the extreme river depth observed, which is 240 m. e structure was also xed on two components representing the ground connection between the car and the soil of the water.is work tested four models (two for each material NC and MC); each model with the same conditions represents di erent behaviors, as expected.Results for aluminum in NC and MC are presented for both of the structures; furthermore, the results obtained for the steel alloy will be presented.Both structures were tested and analyzed in two ways, tensile analysis (Tables 3 and 4) and safety factor analysis (Tables 5 and 6).ey were obtained from Von Misses theorem; these results were calculated with Solid Works tools through nite element analysis.e results were analyzed in terms of minimum tension (MT) and safety factor (SF); the best result was obtained with the aluminum alloy with 134.906 of MT and 4.64 in SF, which refer to the NC structure.is represents that the structure has mechanical characteristics that allow its use for the proposed application.

Results
It was very important for this study to apply the Solid Works environment for design and test analysis; its properties facilitated the process and its changes, which will improve the structure for the nal purpose.
Future works will improve in the structure of new equipment and components, so, the models will have to be re-validated for new con gurations or changes that could arise.
We thank Capes, CNPq for doctoral scholarships and nancial help for investigation.