Structural design considerations for a Personnel Launch System

For decades, structural design has erroneously been taught to architecture students using a modified version of an engineering-based pedagogical model. Instead of imparting a broad range of information for how structural design considerations could be critically integrated into architectural design, these courses instead focus on a narrow range of curricular topics and analytical methods that negatively impact the preparedness of architectural students for practice. To help address these deficiencies, the entire building technology course sequence at Iowa State University, has been dramatically reconfigured as a collaborative and integrative teaching environment that uses active learning environments and unique classroom activities to enhance student learning. Specifically this paper will present three different labs that occur during the final five-week course module of this structural design sequence. Each of the three exercises demonstrates particularly important, capstone-level, learning objectives. The paper will describe the means, methods, challenges, and benefits of these specific assignments and how these represent other important improvements throughout the new sequence. Examples of student work will be shown, and an assessment of the efficacy of the assignments will be presented including reflections upon lessons learned and suggestions for future improvements. INHERENT INEFFECTIVENESS Effectively teaching structural design to architecture students is an important, but complicated process. At its most basic level, architectural education teaches ways to create accommodating and experiential spaces and forms, yet the extent of possible responsive solutions requires the coalescence of a multiplicity of diverse cultural, aesthetic, and technological considerations. Although design is a reiterative process that rarely has a single correct or obvious answer, there are aspects, like structural design, that do require quantifiable verification for viability. Therefore, designing requires an ability to experiment and evaluate different arrangements and assembly options using both qualitative and quantitative analytical means and objectives. Learning these different skills can be complex and confusing, especially because these skills are frequently taught quite differently. Unfortunately, for the last fifty years, structural design has been predominantly taught to architecture students in a manner more in line with an engineering education. By continuing to base the course content and pedagogical approach primarily on calculation-based means of analytics and evaluations practiced by the engineers,

This paper presents structural modeling and design considerations for a double-layer shoring system made of wood posts based on analytical derivation, numerical computation, and the LeMessurier formula. Simplified two-dimensional models of double-layer shoring systems are developed. The analysis shows that system critical loads do not increase with the addition of individual pinned-ended shores, i.e., leaning columns, in the system during construction. If these individual pinned-ended shores are widely used, more cases of falsework failure may occur. The effects of lengths of horizontal stringers and vertical shores, stiffnesses of stringers, and positions of strong shores are investigated in the paper. The reinforcement by addition of bracing to the shoring systems can improve the system buckling strength. The study concludes that appropriately fastening a group of pinned-ended shores with horizontal bracings, i.e., strong shores, can increase the load-carrying capacity of a double-layer shoring system.

A Deck Mating System is entrusted to facilitate the transfer a topsides facility by Floatover method from a free-floating transport vessel to a fixed or floating substructure. These critical systems have moving parts, complex dynamic properties, and structural design considerations that are little understood by most designers. Yet, these systems may be employed with inadequate engineering, design and analysis. They may be manufactured and assembled by multiple, generalized contractors, rather than by a single, specialized vendor. And they may have their function tested for the first time during the actual Floatover operation. There are inherent risks in this type of operation, and failures have occurred. As a result, some clients have grown more cautious. They have tightened specifications, limited procurement to specialized vendors, and required comprehensive testing of a fully assembled unit. Fortunately, no failure has yet resulted in the total loss of a topsides. However, as there has been no dramatic, publicized failure, many clients continue to cut corners on this critical area and test poorly designed, engineered, and manufactured system in the field. Primarily, this paper seeks to assist a designer, purchaser, or end user of a Deck Mating System by pointing out critical design considerations and by providing a set of recommended practices. The paper first provides a brief overview of the components of a Deck Mating System and their functions. It then outlines the potential design hazards, from obvious, catastrophic failures to often hidden failures to meet performance requirements. Finally, a list of recommended practices is provided in the form of an example specification. This paper draws from experience through 18 floatover operations and a larger number of design developments and engineering studies.

The Pier E Redevelopment Project targets reconfiguring and combining two irregularly shaped adjacent container terminals to establish a more efficient and environmentally friendly facility. This project aims at replacing the existing wharf structures with modern structures over wharf slope areas stabilized by rock dike revetment or ground improvement. Also, the existing Pier E wharf will be rehabilitated and widened to accommodate a 137'-9 gauge crane, and eventually extended to the south to connect with the wharf at the Pier F terminal. The wharf layout consists of a 4,250-foot long berth composed of 6 wharf segments separated by transverse expansion joints. The design of the wharf considers variation in soil properties and proposed wharf slope stabilization solutions at the different wharf segments. This paper addresses the wharf structural design considerations. A performance based approach was used for the seismic design of the wharf structure for inertia and kinematic loading. The design philosophy objective is to provide a ductile structure with plastic hinges forming in the piles to dissipate the earthquake energy. A series of non-linear static pushover analyses that consider the nonlinear soil behavior were performed to evaluate the structure's displacement capacity and shear demand. The substitute structure method was used to calculate the seismic displacement demands for three levels of ground motions. A non-Linear Time History Analysis was performed for the linked wharf units to verify the displacement demands and determine shear key forces. Pier E utilizes a wider gauge crane with a higher vertical load and translational elastic period of the mode with the maximum participating mass being about 1.3 to 1.5 seconds. The wharf seismic design considered the crane mass impact on the wharf displacement demand. Copyright 2010 ASCE.

Anisotropic size effect of 3D printed LC3-based engineered cementitious composites (LC3-ECC)

In the aircraft manufacturing industry, the strength and weight of the material is one of the important considerations in structural design. Composite material is a material composed of two or more forming materials, each of which has different mechanical properties. Aircraft structure in this era are 50 - 80% composed of glass or carbon fiber composite materials as reinforcement. Unfortunately, these fibers when recycled produce harmful CO gas, difficult to degrade naturally and cause itching when in contact with human skin. For this reason, environmentally friendly and strong fibers are needed to replace the role of glass or carbon fibers. Is a bamboo plant, which is abundant in Indonesia which is considered suitable as a substitute material. In this study, a mechanical test and descriptive analysis were carried out on the strength of the composite material with variations in the types of bamboo fibers apus, wulung, tutul and petung. These fibers are arranged with epoxy resin and hardener as a binding material (matrix). And each fiber will be arranged in 0 ° pattern to the matrix. Then each material with a different fiber type will be tested for tensile and bending to obtain the value of stress and strain that occurs at its maximum loading. And the result is the average tensile stress value (Mpa) composite material of apus bamboo is 75.95, wulung bamboo 49.92, petung bamboo 112.73, tutul bamboo 83.85. Then the average bending stress (Mpa) composite material of apus bamboo was 239.073, wulung bamboo 214.236, petung bamboo 249.67, tutul bamboo 272.79. With this result, bamboo fiber composites are considered to be able to replace the role of carbon or glass fibers, as an alternative composite material in some parts of the interior fuselage of aircraft panels. Keyword: Composites material, Matrix, Bamboo Fibers, Carbon and Glass Fibers, Stress and Strain.

Natural hazards like cyclones cause significant loss of life and damage to properties, ecosystems and marine structures and facilities. Numerical modelling of cyclones is carried out for deriving robust design conditions for coastal and marine structures and facilities. Cyclone modelling results are also used for emergency planning and decision-making to estimate potential loss of life, damage to properties and marine facilities and to develop rescue and mitigation measures and plan clean-up operations. Royal HaskoningDHV (RHDHV) has set up regional tidal hydrodynamic and wave transformation models covering the Arabian Sea to address the above issues. Cyclone Mekunu is relatively new (May 2018). A quick literature search by Royal HaskoningDHV has suggested that numerical modelling results of waves and surge on Cyclone Mekunu are hardly available in the public domain. Therefore, this paper has concentrated on this event to illustrate the use of numerical modelling to simulate waves and surge generated by cyclones. The MIKE21 model of DHI was used in the study. Sample results of waves and surge from the modelling study are presented in this paper for illustration purposes. Structural design considerations and cyclone risk reduction measures are also provided. The model could be used to simulate any cyclone generated anywhere within the Arabian Sea. The methodology described in this paper for modelling cyclone waves and surge in the Arabian Sea could also be applied to simulate cyclones at other sites around the world. The paper provides valuable information to the researchers and practitioners of the region on this relatively new event.

The structural support system for two equilibrium field coil conductor concepts is considered for the fusion energy design (FED) 8/10T baseline magnetic fusion system. Both conductor concepts are discussed. Results indicate that regardless of the conductor concept employed, an external support beam/frame structural system is required to equilibrate the accumulative loadings.

Precast and prestressed concrete played a prominent role in meeting the stiff requirements of the new USAA Southeast Regional Office Building and Parking Structure in Tampa, Florida. The seven-story office building and five-level parking structure are separated into two curving volumes facing an existing man-made lake. These volumes unite to form a single south facade characterized by a large-scale grid of punched windows in a horizontally banded exterior wall. The free standing 1600-car parking structure is all-precast, employing a distinctive loadbearing ladder wall system with a pretopped double tee floor system. The authors present the architectural requirements and environmental issues, the structural design considerations and some production/erection highlights of the proiect. A key ingredient, which ensured the success of the project, was the concept of partnering ― the theme of which is carried throughout the article

Research of advanced power cycles has shown supercritical carbon dioxide power cycles may have thermal efficiency benefits relative to steam cycles at temperatures around 500–700°C. To realize these benefits for CSP, it is necessary to increase the maximum outlet temperature of current tower designs. Research at NREL is investigating a concept that uses high-pressure supercritical carbon dioxide as the heat transfer fluid to achieve a 650°C receiver outlet temperature. At these operating conditions, creep becomes an important factor in the design of a tubular receiver and contemporary design assumptions for both solar and traditional boiler applications must be revisited and revised. This paper discusses lessons learned for high-pressure, high-temperature tubular receiver design. An analysis of a simplified receiver tube is discussed, and the results show the limiting stress mechanisms in the tube and the impact on the maximum allowable flux as design parameters vary. Results of this preliminary analysis indicate an underlying trade-off between tube thickness and the maximum allowable flux on the tube. Future work will expand the scope of design variables considered and attempt to optimize the design based on cost and performance metrics.

NASA's upcoming ARES V launch vehicle, with its' immense payload capacities (both volume and mass) has opened the possibilities for a whole new paradigm of space observatories. It becomes practical to consider a monolith mirror of sufficient size to permit significant scientific advantages, both in collection area and smoothness or figure at a reasonable price. The technologies and engineering to manufacture and test 8 meter class monoliths is mature, with nearly a dozen of such mirrors already in operation around the world. This paper will discuss the design requirements to adapt an 8m meniscus mirror into a Space Telescope System, both launch and operational considerations are included. With objects this massive and structurally sensitive, the mirror design must include all stages of the process. Based upon the experiences of the Hubble Space Telescope, testing and verification at both component and integrated system levels are considered vital to mission success. To this end, two different component level test methods for gravity sag (the so call zero- gravity simulation or test mount) are proposed, with one of these methods suitable for the full up system level testing as well.

<div class="htmlview paragraph">The 1980 requirements for bumpers limit the damage that may be sustained in 8 km/h (5 mph) pendulum and barrier impacts. This paper covers four items of interest for design of one-piece aluminum bumpers: (1) properties of alloys, (2) dent resistance, (3) beam strength, (4) relative behavior of aluminum and steel.</div> <div class="htmlview paragraph">Static and dynamic tests are used to define the effects of yield strength and thickness on denting. Finite element calculations agree well with the results of dynamic bending tests of bumpers. Data presented also show that the strain rates during beam bending are low. Relative weights of aluminum and steel bumpers are defined.</div>

<div class="htmlview paragraph">The Aluminum Structured Vehicle Technology (ASVT) program in Alcan is developing technology for the design and manufacture of adhesively bonded aluminum automobile structures. The development of any new vehicle involves a complex balance between package, manufacture, cost and performance constraints, and it is therefore important to be able to give clear guidelines in these areas to support the evaluation of this new technology by the motor industry.</div> <div class="htmlview paragraph">This paper on ASVT structural design demonstrates the important features involved in meeting strength and stiffness needs at minimum weight, and it is intended to complement previous publications which have focused on the core technology and process considerations of ASVT.</div> <div class="htmlview paragraph">The first two sections examine the key elements of ASVT, namely the aluminum and the adhesive bond, with both strength and stiffness being considered. The final two sections examine the large influence of ASVT on the performance of connections between structural members, and the resulting stiffness of structures as a whole.</div>

During the 1970's through the early 1990's, NASA Langley Research Center (LaRC) conducted studies for the design and construction of large space structures in Low Earth Orbit (LEO). The Langley studies focused on the design and construction of erectable space structures. The construction studies evaluated assembly methods using astronauts with and without mechanized foot-restraints. Astronaut construction was shown to be very effective and efficient when the structure and the construction methods were developed in parallel. This paper presents an overview of the LaRC astronaut construction studies of erectable structures, including a database of assembly rates and lessons learned. In addition this paper presents potential applications of erectable structure assembly methods using EVA astronauts and a suggested integrated approach for construction of large space structures.

Planning future Multi-Domain Battle (MDB) missions requires extensive, complex, and real-time collaboration and coordination between many Warfighting Functions and Domains such as Electronic Warfare (EW), Positioning, Navigation and Timing (PNT), Network Operations, and Cyber Operations. This collaboration and coordination requires synchronization of the associated domain processes and activities. Large Infrastructure projects for Command and Control (C2) are designed to integrate and align these processes through Information Technology (IT) services, such as decision aids, collaboration tools, and communication tools. New acquisition initiatives are driving infrastructure development to support the rapid fielding of capabilities through a modular software development approach. State-of-the-Art Shared Infrastructure Services can be developed using Agile Software Development (ASD) methods such as Scrum, Kanban, or Extreme Programming. However, the integration of these IT services cannot be easily planned since they are developed at the technology (i.e., software implementation) level according to the selected ASD method. Engineering the Infrastructure as Code (IaC) results in a gap between doctrinal processes and required system functionality since developers quickly code and configure small functional modular units at the technology level, while bypassing the traditional top-down waterfall flow from requirements to design. Furthermore, IaC does not explicitly require consulting a systems architecture. To improve the alignment of configured IT infrastructure services with doctrinal processes, this paper seeks to determine the extent to which agile Development Operations (DevOps) process can implement C2 doctrine while supporting dynamically-changing mission requirements and an operational environment. This paper proposes an automated Systems Engineering workflow to realize IT infrastructure services using Model-Driven Architecture (MDA) and a military DevOps.