Overdesigned

The pump should be specified for the right flow. As Figure 9 shows, a 50% overdesign factor increases power by 35% in a combination of higher head and lower efficiency (see Pumps). 

Because normal radioisotopic decay lowers the thermal output by about 2.5%/yr in these units, they are purposefully overdesigned for beginning of life conditions. Several of these generators have successfully operated for as long as 28 years. This is approximately equal to the half-life of the strontium-90 isotope used in the heat sources. The original SNAP-7 series immobilized the strontium-90 as the titanate, but the more recent ones have used it in the form of the fluoride, which is also very stable. A number of tiny nuclear-powered cardiac pacemaker batteries were developed, which have electrical power outputs of 33—600 p.W and have been proven in use (17). 

A key feature implicitly included in the use of organic fibers for tire reinforcement is the abiHty to retain strength and modulus characteristics at elevated temperatures (80—120°C for most tires) sufficient to sustain service demands. Thus, a tire which may appear to be overdesigned at room temperature is, in many cases, reflecting the changes in properties experienced at operating temperatures. 

Initial cost of a conveyor system is usually related to life ejqjectancy as well as to the flow rate chosen. There is a great temptation to overdesign, which should be resisted. The first really longdistance belt conveyor was designed and fabricated to extremely hi standards of quality. After 35 years it was still in operation with almost all its original components. Had this operation been planned for only... 

Non-complex and/or non-critical applications in mechanical design can also make use of probabilistic design techniques and justify a more in-depth approach if the benefits are related to practitioners and customers alike. Surveys have indicated that many products in the industrial sector have in the past been overdesigned (Kalpakjian, 1995). That is, they were either too bulky, were made of materials too high in quality, or were made with unwarranted precision for the intended use. Overdesign may result from uncertainties in design calculations or the concern of the designer and manufacturer over product safety in order to avoid user injury or... 

To ensure no excess of material or overdesign occurs (high costs, weight, mass, volume, etc.). 

The major assumption in weak link design is that the eost of failure of the maehine that is to be proteeted from an overload situation in serviee is mueh greater than the eost of failure of a weak link plaeed in the system whieh is designed to fail first. The situation is primarily driven by various eosts whieh must be balaneed to avoid at one extreme the eost of failure of the system, and the other overdesign of the elements in the system. The eost faetors involved are typieally ... 

However, too great a separation, and overdesign may oeeur. The overload eondition is represented by a unique stress, whieh is very mueh greater than the working stress, applied suddenly whieh eauses only the weak link to failure due to stress rupture. 

Again, a preferred value for the aetual seetion width would be Z) = 110 mm. In a more simplified way than that presented in Seetion 4.8.4, we have separated the failure of the pin from the eon-rod by approximately 3 + 3 strength standard deviations. The aetual separation ean be modelled for the distribution of the shear foree in the pin and tensile foree in the eon-rod, as illustrated in Figure 4.69. The safety margin, SM, is ealeulated to be 4.61, or defined another way, the reliability R = 0.999998 whieh is adequate for the applieation to avoid overdesign of the eon-rod. 

Process Conceptual Design Equipment selection and sizing Inventory of process Single vs. Multiple trains Utility requirements Overdesign and flexibility Recycles and buffer capacities Instrumentation and control Location of plant Preliminary plant layout Materials of construction As above plus equipment suppliers data, raw materials data, company design procedures and requirements... 

Standard shapes for composite stiffeners are not likely to occur for most aerospace applications. There, the value and function of the structure warrant optimizing the stiffener design. In contrast, for more everyday applications such as scaffolding, stairways, and walkways in chemical plants, competitive pressures lead to a situation where compromises in stiffener efficiency are readily accepted (overdesign) in order to achieve lower cost than would be associated with optimum design. 

The key to the design of efficient laminates is to resist both the magnitude and the directional nature of the loads without overdesign in either respect. That is, the laminate is taiiored to just meet specific requirements. Structures made of isotropic materials are usually inefficient, i.e., overdesigned because excess strength and stiffness are inevitabiy available in some direction. By appropriate consideration of the loads and their directions, a laminate can be constructed of individual laminae... 

The fit of the data to the proposed equation is on average 30% overdesign, which is good in terms of boiling data and when compared to the Gilmour s bundle coefficient of +48% and Kern s +61%. ... 

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