Solvability of a hybrid model for a vertical slender structure

We consider the solvability of a hybrid model for the vibration of a vertical slender structure mounted on an elastic seating. The slender structure is modeled as a Rayleigh beam and gravity is taken into account. The seating and foundation block are modeled as rigid bodies connected by elastic springs with damping mechanisms. We show how an existence result for a general linear vibration problem in variational form may be applied to the weak variational problem for this system

Aeronautical engineering: A continuing bibliography with indexes, supplement 146, March 1982

This bibliography lists 442 reports, articles, and other documents introduced into the NASA scientific and technical system in February 1982

A full-scale laboratory investigation into railway track substructure performance and ballast reinforcement

To reduce railway track maintenance costs and meet the growing demand for rail travel the railway industry needs to significantly increase the performance of old existing tracks and design any new tracks accordingly. In this thesis, a new full-scale laboratory Geopavement & Railway Accelerated Fatigue Testing (GRAFT) facility at Heriot-Watt University is developed to study the performance of both unreinforced and reinforced railway track substructure systems. The new GRAFT facility enables accelerated testing of full-scale railway tracks and innovative railway products under realistic railway loading conditions. The unreinforced track systems represent typical railway tracks in the UK while the reinforced track systems represent sections of track implemented with various geosynthetic products. GRAFT consists of a track constructed within a steel tank. The track comprises a 750mm clay subgrade layer overlain by a clay formation layer overlain by a 300mm ballast layer. The track includes three hardwood sleeper sections overlain by an I-section steel beam which has similar stiffness properties to a BS 113 A rail section. Cyclic loading is applied to the track from a hydraulic testing machine with the centre sleeper directly under the loading actuator. The loading mechanism replicates a repeated quasi static single wheel load on the central sleeper of one half of a 3m long section of railway track. Based on the results found from the testing programme in GRAFT empirical relationships are developed between the unreinforced track performance in terms of track settlement and stiffness and the subgrade modulus, applied load and number of applied cycles. These relationships fit the GRAFT data presented in this thesis well and it is thought that they could be used (tentatively) to estimate track settlement on track after tamping/ballast renewal/new track. These relationships are shown to be consistent with other well known track settlement models and they indicate that subgrade stiffness and applied vertical load are two of the most significant parameters that influence track substructure deterioration. The results found from the reinforced track tests quantify the improvement in track performance available with each product under various track conditions. Two ballast ii reinforcement products have been tested; XiTRACK reinforcement and geocell reinforcement, along with a reinforced geocomposite used primarily for separation at the ballast/subgrade interface. In addition, a geocomposite product designed to replace a traditional sand blanket, used on the tracks where severe subgrade erosion conditions prevail, has been tested in GRAFT under flooding conditions. The most significant results show that XiTRACK reinforcement can considerably improve the performance of railway tracks while the performance of the track implemented with the sand blanket replacement product indicates that currently a traditional sand blanket with a geotextile separator is the recommended option for tracks with subgrade wet spots. From all the data recorded empirical settlement models are proposed for each of the geosynthetics compared for reinforcement purposes. These models form the basis for reinforced track design graphs that could potentially be used to form part of an initial cost-benefit analysis of different track reinforcement techniques considered for improving track performance and reducing maintenance. In order to use the track settlement design graphs developed within this thesis (in the field) a reliable measure of subgrade stiffness needs to be made on track. A reliable insitu measuring device could enhance railway site investigations. Several in-situ measuring devices that could potentially be used to measures subgrade stiffness and strength in the field have been tested within GRAFT. The devices studied include the Dynamic Cone Penetrometer (DCP), Light Falling Weight Deflectometer (LFWD), Pocket Penetrometer and Proving Ring Penetrometer. The accuracy of these devices is compared to Plate Load Tests (PLT) and unconfined compression strength tests and suggestions towards the use of such devices on track made. The results indicate that the DCP has the potential to be a quick and accurate in-situ measuring device for railway track site investigations. The GRAFT facility and the results found in GRAFT have been validated using a basic static 3D FE computer model termed SART3D (Static Analysis of Railway Track 3D). The program has been calibrated to GRAFT by modifying the FE mesh for the dimensions of GRAFT and inputting the GRAFT track properties. The validated results from this thesis have direct practical implications to the railway industry in terms of iii design recommendations on how best to investigate and improve key geotechnical parameters that influence railway track performance and hence reduce maintenance costs and extend asset life. A review of current design procedures used in the railway industry is given and a new design procedure is suggested to reduce track maintenance and offer an optimised design and maintenance strategy

Aeronautical Engineering. A continuing bibliography, supplement 112

This bibliography lists 424 reports, articles, and other documents introduced into the NASA scientific and technical information system in July 1979

Seismic precast: seismic performance assessment of existing precast industrial buildings

No abstract available.publishe

KINE[SIS]TEM'17 From Nature to Architectural Matter

Kine[SiS]tem – From Kinesis + System. Kinesis is a non-linear movement or activity of an organism in response to a stimulus. A system is a set of interacting and interdependent agents forming a complex whole, delineated by its spatial and temporal boundaries, influenced by its environment. How can architectural systems moderate the external environment to enhance comfort conditions in a simple, sustainable and smart way? This is the starting question for the Kine[SiS]tem’17 – From Nature to Architectural Matter International Conference. For decades, architectural design was developed despite (and not with) the climate, based on mechanical heating and cooling. Today, the argument for net zero energy buildings needs very effective strategies to reduce energy requirements. The challenge ahead requires design processes that are built upon consolidated knowledge, make use of advanced technologies and are inspired by nature. These design processes should lead to responsive smart systems that deliver the best performance in each specific design scenario. To control solar radiation is one key factor in low-energy thermal comfort. Computational-controlled sensor-based kinetic surfaces are one of the possible answers to control solar energy in an effective way, within the scope of contradictory objectives throughout the year.FC

Aeronautical engineering: A continuing bibliography with indexes (supplement 201)

This bibliography lists 438 reports, articles, and other documents introduced into the NASA scientific and technical information system in May 1986

Study of Finite Elements-based reliability and maintenance algorithmic methodologies analysis applied to aircraft structures and design optimization

This thesis presents the development of a research methodology oriented to the analysis of an aircraft structure in terms of operational reliability and maintainability requirements regarding its airworthiness. The study has been focused on modern commercial aircraft models, carrying out a market research and model selection according to different criteria. The study then develops a practical implementation consisting of the design approach of the aircraft airframe and main structural components for its subsequent numerical analysis and simulation. The numerical simulations will be computed by application of the Finite Elements Method on the main structural systems of the aircraft and establishment of boundary conditions. These simulations will allow the development of a computational study on linear, non-linear, and transient simulations of static loads, buckling, modal analysis, temperature, fatigue and thermal stress of individual structures and full assembly in different conditions. Finally, these results will be assessed and exported to a Matlab code which will compute an algorithmic methodology in order to approach the operational reliability and safety of the aircraft in the studied conditions. The thesis will conclude with a review of airworthiness regulations a proposal of research paths and further development of the methodology implemented

Aeronautical engineering: A cumulative index to a continuing bibliography

This bibliography is a cumulative index to the abstracts contained in NASA SP-7037(210) through NASA SP-7037(221) of Aeronautical Engineering: A Continuing Bibliography. NASA SP-7037 and its supplements have been compiled through the cooperative efforts of the American Institute of Aeronautics and Astronautics (AIAA) and the National Aeronautics and Space Administration (NASA). This cumulative index includes subject, personal author, corporate source, foreign technology, contract number, report number, and accession number indexes

Aeronautical Engineering: A continuing bibliography, 1982 cumulative index

This bibliography is a cumulative index to the abstracts contained in NASA SP-7037 (145) through NASA SP-7037 (156) of Aeronautical Engineering: A Continuing Bibliography. NASA SP-7037 and its supplements have been compiled through the cooperative efforts of the American Institute of Aeronautics and Astronautics (AIAA) and the National Aeronautics and Space Administration (NASA). This cumulative index includes subject, personal author, corporate source, contract, and report number indexes