Performing Department
(N/A)
Non Technical Summary
Even with efforts to expand network coverage, there are still 18 million Americans without broadband access with nearly a quarter of rural Americans without broadband access. The importance of closing the digital divide in network coverage between urban and rural areas has never been as apparent as during the recent worldwide pandemic. Lack of network access in rural areas prevents or disadvantages telehealth resources, distance learning, ecommerce, and remote work opportunities for residents and potential tourists. Events and programs such as traveling healthcare and tourist attractions may not be feasible without adequate available network coverage.This project proposes to create mobile cell sites that can provide temporary coverage quickly and easily. IsoTruss Inc. designs and manufactures patented composite lattice structures that reduce weight by 12X compared to steel structures without compromising strength. These structures have been successfully applied to rural telecom towers because of their reduced weight and significantly lower installation and maintenance costs. In this project, IsoTruss will utilize its patented geometry to create a lightweight, space-saving mobile cell site that can be assembled and disassembled quickly without additional equipment. The proposed mobile cell site will save space, weigh less and last longer than current options. Expanded network coverage will improve rural community economies and quality of life by accommodating large sporting events, concerts and other tourist attractions. Mobile cell sites will also provide network access quickly during natural disasters when existing networks are damaged. The space and weight savings of the IsoTruss product will allow these mobile cell sites better transport and assembly in disaster-stricken areas.
Animal Health Component
60%
Research Effort Categories
Basic
10%
Applied
60%
Developmental
30%
Goals / Objectives
This project proposes to create mobile cell sites that can provide temporary coverage quickly and easily. IsoTruss Inc. designs and manufactures patented composite lattice structures that reduce weight by 12X compared to steel structures without compromising strength. These structures have been successfully applied to rural telecom towers because of their reduced weight and significantly lower installation and maintenance costs. In this project, IsoTruss will utilize its patented geometry to create a lightweight, space-saving mobile cell site that can be assembled and disassembled quickly without additional equipment. The proposed mobile cell site will save space, weigh less and last longer than current options. Expanded network coverage will improve rural community economies and quality of life by accommodating large sporting events, concerts and other tourist attractions. Mobile cell sites will also provide network access quickly during natural disasters when existing networks are damaged. The space and weight savings of the IsoTruss product will allow these mobile cell sites better transport and assembly in disaster-stricken areas.
Project Methods
Technical Objective 1: Telescoping IsoTruss structureThe purpose of telescoping is to reduce the space taken by the tower structure when the network is not in use. Space savings will impact the equipment needed for transport and the space needed for storage. The telescoping IsoTruss structured will be designed with the goal to fit on the back of a 10-foot trailer that can be pulled by a light-duty truck. By creating tower sections that can fit inside one another, it is possible to save space during storage and transport while still having the optimal tower height to receive quality network access.Telescoping can be accomplished with straight tower sections at varying diameters or tapered tower section. Both tower designs will be considered during the feasibility study in terms of material usage, manufacturing costs including tooling and labor, and weight savings.IsoTruss telecom tower structures are currently straight sections, however, tapered structures are more optimized for weight where bending loads are the primary force seen by the structure. With the appurtenance weight toward the top of the tower and a distributed wind load that increases with height, the highest force will be at the bottom of the structure. Tapering, therefore, adds to the moment of the inertia at the bottom of the tower where the extra strength is needed without adding unnecessary weight to the rest of the structure. The weight and strength benefits of tapered structures come with added complexity in manufacturing, which may make straight sections the better option. One of the challenges with straight tower sections is the connection between two sections connecting two different diameters. This connection task is not impossible, but the complexity will be considered in determining where to use straight or tapered sections.Careful design work will consider the various diameters of different tower sections to ensure that they properly nest during storage and transport without damage or difficult assembly. The tower weight and height will determine the ease of assembly during deployment. IsoTruss will target a tower that can be assembled on site without additional cranes or other machinery.Much of the analysis for tapered versus straight sections can be done analytically. IsoTruss already has derived equations to compare the two sections in weight and mechanical strength. The two possible designs will also be designed in computer-aided design (CAD) software and stresses evaluated with finite element analysis. IsoTruss uses RISA3D, a CAD software for truss structures. The RISA software allows IsoTruss to visualize the performance of the structure under specified loading conditions and because it is specific to truss structures the software is much faster than typical finite element analysis. The speed of analysis will allow IsoTruss to analyze the two structures in various geometries and loading conditions to have a thorough understanding of the structure performance.After the analysis of both straight and tapered structures, IsoTruss will select the best geometry for mobile cell structures for weight, strength, material and labor costs, and assembly/disassembly. Part of the analysis process will include 3D printing scaled models to visualize the sections. This project will use a Creality 10S4 3D printer owned by IsoTruss in the IsoTruss Innovation Center. Physical 3D printed models will allow better analysis of the designs and illuminate issues not realized in computer generated models. The final selection will then be used to create a CAD model for a prototype that can be tested during the Phase II project. This model will be included with the final project report.Technical Objective 2: Connection methodsIsoTruss telecom tower products are connected with flanges and bolts. The bolts are attached parallel to the height of the tower so that they do not experience the full bending load. These connections are always permanent, unlike mobile cell sites where the tower will be repeatedly put up and taken down.The emphasis for the connection methods during this feasibility study will be the ability to quickly deploy and take down the structure. Traditional flanges and bolts are the easiest solution and will work for this application, but other solutions may make for faster assembly. For example, there could be spring-loaded pins in each tower section that extend at specific heights. The potential connection methods will be evaluated for their cost, performance, and ease of assembly/disassembly.The research and development work for connection methods will start with idea evaluation. The various connection method ideas will be evaluated for ease of disassembly/assembly, cost, and strength. IsoTruss will create a matrix with the criteria weighted by importance. The top two ideas will be selected for further research. Models of the ideas will be created in Fusion360 because of the higher complexity with the connection pieces as opposed to the tower itself which is made up of truss structures. Fusion360 can also be used as the finite element design software to evaluate the strength and stress behavior of the design. As the design of the sections will be influenced by the design of the connection methods, the two tasks will be performed simultaneously. The process of designing connection methods will pay special attention to manufacturability. For this reason, manufacturing consideration is listed as a separate task on the Gantt chart. Stock items for bolts and other hardware will be preferred for cost reasons over custom items if possible. Manufacturing consideration will also include the manufacturing of the tower sections and the assembly/disassembly of the final product.The efforts to understand and select a suitable connection method will result in a prototype design that will be built as part of the Phase II project.