Various other options should be obvious to those skilled in the art. 1 and a further enlarged view of the potted permeate fabric of the element, respectively. 4 the outer ring is the pressure vessel 2 into which is fitted the product-side end cap 9b.

Structural and thermal bricks exist so the same model geometry can be used for both the initial steady state heat transfer and subsequent thermal stress computations. 2D Elements are 3 or 4 node elements with only 2 DOF, Y and Z translation, and are normally created in the YZ plane. Common applications include axisymmetric bodies of revolution such as missile radomes, radial seals, etc. and long sections with constant cross sectional area such as a dam. Plane Stress implies no stress normal to the cross section defined – strain is allowed – suitable to model the 2D cross section of a body of revolution.

The direction of the vector is considered as the local direction. Then the vectors and define the plane which is tangential to the element surface. The normal vector to this plane can be obtained by the vector cross product of and , which is the local direction. At last, the local axis is obtained by the vector cross product of the vector in the local direction and vector in local direction. Now the local Cartesian coordinate system in which the axes and are tangential to the surface and is directed in the normal direction is established successfully.

5 and 5a are views of the non-recessed portion of the membrane element 1 of FIG. 5 the solid spiralling lines represent the membrane sheets 15 and the spaces between represent the feed-concentrate and permeate flow channels with spacers and adhesive 7a omitted. Openings contained in feed end cup 9a allow the concentrate to pass out of the circumferential chamber 8 into an open space about a feed nozzle 12 and thence exit from the pressure vessel 2 through a concentrate nozzle 13.

Once the static calculation has been approved by the building authorities, the construction drawings are prepared. Particularly with regard to design elements, these have to be coordinated with the planner and client. In contrast to conventional constructions, the weight of the material (approx. 1-1.5 kg/m²) is negligible.

The cantilevered beam shown in Figure 4 is meshed by five irregular quadrilateral membrane elements depicted in Figure 6. Two cases of loading are considered, Load 1 is the force couple acting at the two corners on the free end, and Load 2 is two equal transverse forces acting at the two corners. The numerical results given by QCQ4-1 and QCQ4-2 are tabulated in Table 4 together with the results given by a number of other popular quadrilateral membrane elements for comparison.