Aerolastic tailoring and integrated wing design

Much has been learned from the TSO optimization code over the years in determining aeroelastic tailoring's place in the integrated design process. Indeed, it has become apparent that aeroelastic tailoring is and should be deeply embedded in design. Aeroelastic tailoring can have tremendous effects on the design loads, and design loads affect every aspect of the design process. While optimization enables the evaluation of design sensitivities, valid computational simulations are required to make these sensitivities valid. Aircraft maneuvers simulated must adequately cover the plane's intended flight envelope, realistic design criteria must be included, and models among the various disciplines must be calibrated among themselves and with any hard-core (e.g., wind tunnel) data available. The information gained and benefits derived from aeroelastic tailoring provide a focal point for the various disciplines to become involved and communicate with one another to reach the best design possible

Recent experiences using finite-element-based structural optimization

Structural optimization has been available to the structural analysis community as a tool for many years. The popular use of displacement method finite-element techniques to analyze linearly elastic structures has resulted in an ability to calculate the weight and constraint gradients inexpensively for numerical optimization of structures. Here, recent experiences in the investigation and use of structural optimization are discussed. In particular, experience with the commercially available ADS/NASOPT code is addressed. An overview of the ADS/NASOPT procedure and how it was implemented is given. Two example problems are also discussed

NDM-556: WIND UPLIFT RESISTANCE DESIGN OF A GREEN ROOF

Green roofs, also referred to as vegetated roofs, have increased in popularity in recent years in North America. Traditionally their use had been more prominent in European countries, such as Germany, however the North American design community have recently adopted them, thanks in part to programs such as LEED and the City of Toronto’s Green Roof Bylaw. Toronto’s Green Roof Bylaw mandates “green roofs on new commercial, institutional and residential development with a minimum Gross Floor Area of 2,000m2 as of January 31, 2010”. Also contained within the aforementioned Green Roof Bylaw is a requirement that the submitted green roof design explicitly state the uplift wind pressures that it has been designed for, and how the design addresses the stated pressures. This report needs to be stamped by a Professional Engineer. This requirement has led to many questions regarding the wind resistance of a green roof, which is a unique building material in many ways - it is organic, living, porous, and has a variable weight (based on the amount of water it is retaining). Conventional building materials have strict tolerances and highly standardized, whereas the properties of green roofs change on a daily basis. The intent of this paper is to discuss the design of a green roof in order to prevent lift off/fly away of a green roof assembly. The methods presented are based on applicable standards and building codes, as well as specific testing that has been undertaken on a green roof system to demonstrate its porosity and pressure equalization properties

Anthelmintic resistance in cattle

Parasitic nematode infections can affect all ages of cattle, but are mainly of clinical significance in young parasite-naïve calves in their first year at grass, or in second-year grazers (Figure 1). For these animals, several control and worming strategies have been advocated that have proved successful – particularly since the launch of the macrocyclic lactone (3-ML) class of anthelmintics, which now dominate the cattle “wormer” market

Outlook and appraisal [November 1985]

The Scottish economy, like that of the UK as a whole, looks set to experience a substantial shift in the relative importance of the factors determining growth in the coming year. As discussed elsewhere in the Commentary (see British Economy), growth in the recent past has been driven mainly by the expansion of investment and exports. With the interrelated factors of sterling's strength and continuing high real UK interest rates operating against a background of some deceleration in the growth of world trade, the prospect is that these influences will be largely replaced by the re-emergence of consumers' expenditure as the principal determinant of growth

The Scottish economy [November 1985]

With the inauguration of the quarterly Scottish Business Survey (SBS) in September 1984 there are now two regular up-to-date indicators of trends in the Scottish industrial sector. The combination of the new survey and the long-standing CBI Industrial Trends Survey provides a comprehensive assessment of trends in Scottish industry

The British economy [November 1985]

In his November Statement the Chancellor of the Exchequer has forecast continuing expansion of the economy during 1986. The recent growth of exports and investment is not expected to be maintained but consumer spending, boosted by higher real earnings and tax cuts in the Spring Budget, will rise

The British economy [August 1985]

The pace of economic growth rose above the underlying growth rate in the first half of 1985 as a consequence of recovery from the miners' dispute and first quarter bunching of investment expenditure. In response to higher interest rates and the Chancellor's continuing commitment to the Medium Term Financial Strategy, sterling has strengthened and has remained resilient in the face of continuing uncertanties concerning oil prices. Output is set to grow by more than 3% this year before falling back as the impetus of the rebound from the miners' dispute diminishes and investment expenditure slackens. This slowdown in activity is likely to be reinforced by the current levels of the exchange rate and of interest rates

The world economy [August 1985]

The recovery in the world economy which began in 1982 now appears to be moving out of its fastest growth phase. With the US economy growing more slowly in the first half of 1985 than in the corresponding period of 1984, the previous marked differences in growth rates between the US and the European economies are being eroded. Indeed, a number of European countries look set to achieve faster growth during 1984 than the US. Largely due to slower US growth, world trade is likely to expand this year by around 5J-6S as compared to 9% last year. The Bonn economic summit in May and subsequent policy statements provide no indications that the slackening momentum in the world economy is to be compensated for by reflation elsewhere