Frame stiffness

Structural mechanics approach, space frame, stiffness matrix method — 1050 [166]... 

The first type of bonded design for this application was the beaded doubler panel (Fig. 28). This design was fairly successful at addressing the problems with simple riveted structure but had two primary drawbacks. The area under the beads remained a single thickness sheet and was still prone to fatigue. Reducing the unbonded areas under the beads was not a solution because it reduced the overall stiffness of the panel. Secondly, tooling for these panels was complex and not very robust. Autoclave pressure applied to the beaded areas of the doubler would cause them to collapse, so thick frames were fabricated with cutouts for the beads to protect them. A rubber layer bonded to the surface of the frames... 

Hail guards of stiff hardware cloth mounted in a removable frame are used to prevent hail damage to the relatively soft fins in hail-susceptible areas. If damaged just slighdy the performance is not impaired. 

Alloys are solid metallic mixtures designed to meet specific needs (see Section 5.15). For example, the frames of racing bicycles can be made of a steel that contains manganese, molybdenum, and carbon to give them the stiffness needed to resist mechanical shock. Titanium frames are used, but not the pure metal. Titanium metal stretches easily, so much so that it becomes deformed under stress. However, when alloyed with metals such as tin and aluminum, titanium maintains its flexibility but keeps its shape. 

Space frames are structures made up of nodes and struts. When the struts that connect the nodes together are slender, the axial stiffness of the strut becomes the dominant form of stiffness, and the bending stiffness that might be achieved in the attachment of a strut to a node is usually very much smaller, and can often be ignored. 

The braced frame will be designed using static design process based on the capacity of supported members. Bracing provides a stiff system which responds to pressure without-absorbing much energy. 

Biaxially oriented polypropylene (BOPP) films have higher stiffness than cast films and consequently can be used in much thinner gauges. Homopolvmers are used almost exclusively to provide maximum stiffness and water-vapor barrier. Oriented films are produced by the tenter frame and bubble processes. 

However, as shown by Jemmis and Kiran201 and as our data in Figure 10 reveal, the a-bond alternation is weak202 since the a-frame is rather stiff in this mode (see also the kg value of the b2U mode in Scheme 16). What makes the bond alternation more significant is the distortive 7r-component as revealed by the data in Figure 10. The patterns of this -enhancement of bond alternation are elaborated below. 

Recently, the stiff-chain polyelectrolytes termed PPP-1 (Schemel) and PPP-2 (Scheme2) have been the subject of a number of investigations that are reviewed in this chapter. The central question to be discussed here is the correlation of the counterions with the highly charged macroion. These correlations can be detected directly by experiments that probe the activity of the counterions and their spatial distribution around the macroion. Due to the cylindrical symmetry and the well-defined conformation these polyelectrolytes present the most simple system for which the correlation of the counterions to the macroion can be treated by analytical approaches. As a consequence, a comparison of theoretical predictions with experimental results obtained in solution will provide a stringent test of our current model of polyelectrolytes. Moreover, the results obtained on PPP-1 and PPP-2 allow a refined discussion of the concept of counterion condensation introduced more than thirty years ago by Manning and Oosawa [22, 23]. In particular, we can compare the predictions of the Poisson-Boltzmann mean-field theory applied to the cylindrical cell model and the results of Molecular dynamics (MD) simulations of the cell model obtained within the restricted primitive model (RPM) of electrolytes very accurately with experimental data. This allows an estimate when and in which frame this simple theory is applicable, and in which directions the theory needs to be improved. 

Angle irons, both on the door panel as well as on the door frame, all around, give the entire door construction more stiffness and precision of measurement. 

X-ray diffraction studies on frame silk indicate it to be a microcomposite, consisting of a cross-linked, amorphous network (about 55-60%) reinforced by stiff... 

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