Showing papers on "Sandwich panel published in 1992"
TL;DR: In this article, a composite composite panel consisting of carbon fiber-reinforced plastic (CFRP) skins and a syntactic foam core was selected as an appropriate structural concept for the design of wind tunnel compressor blades.
Abstract: A composite sandwich panel consisting of carbon fiber-reinforced plastic (CFRP) skins and a syntactic foam core was selected as an appropriate structural concept for the design of wind tunnel compressor blades. Interleaving of the core with tough interlayers was doen to prevent core cracking and improve damage tolerance of the sandwich. Simply supported sandwich beam specimens were subjected to low-velocity, drop-weight impacts as well as high-velocity, ballistic impacts. The performance of the interleaved core sandwich panels was characterized by localized skin damage and minor cracking of the core. Residual compressive strength (RCS) of the skin, which was derived from flexural test, shows the expected trend of decreasing with increasing size of the damage, impact energy, and velocity. In the case of skin damage, RCS values of around 50% of the virgin interleaved reference were obtained at the upper impact energy range. Based on the similarity between low velocity and ballistic impact effects, it was concluded that impact energy is the main variable controlling damage and residual strength, where as velocity plays a minor role. The superiority (in damage tolerance) of the composite sandwich with interleaved foam core, as compared with its plain version, is well established. This is attributable to the toughening effect of the interlayers which serve the dual role of crack arrestor and energy absorber of the impact loading.
38 citations
TL;DR: In this article, an analysis of Saint-Venant end effects for materials with negative Poisson's ratio is presented, and it is suggested that the slow decay previously predicted for sandwich strips in plane deformation as a result of the geometry can be mitigated by the use of a negative POI material for the core.
Abstract: Results are presented from an analysis of Saint-Venant end effects for materials with negative Poisson's ratio. Examples are presented showing that slow decay of end stress occurs in circular cylinders of negative Poisson's ratio, whereas a sandwich panel containing rigid face sheets and a compliant core exhibits no anomalous effects for negative Poisson's ratio (but exhibits slow stress decay for core Poisson's ratios approaching 0.5). In sand panels with stiff but not perfectly rigid face sheets, a negative Poisson's ratio results in end stress decay, which is faster than it would be otherwise. It is suggested that the slow decay previously predicted for sandwich strips in plane deformation as a result of the geometry can be mitigated by the use of a negative Poisson's ratio material for the core.
28 citations
Patent•
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TL;DR: In this article, a fastener extends through a bushing in a panel for joining the panel to a stationary frame, and an integral collar is fixedly trapped between the collar and the plug head, with the plug distal end abutting the frame for predeterminedly spacing the collar from the frame.
Abstract: A fastener extends through a bushing in a panel for joining the panel to a stationary frame. The bushing includes a tubular plug extending through the panel which includes a head, a shank, and a distal end. The bushing also includes a tubular sleeve extending into the panel and disposed around the plug shank, with an integral collar being fixedly bonded to a back surface of the panel. The panel is fixedly trapped between the collar and the plug head, and the plug distal end abuts the frame for predeterminedly spacing the collar from the frame.
27 citations
01 Jan 1992
26 citations
TL;DR: PANDA2 as mentioned in this paper is a computer program for minimum weight design of composite, stiffened cylindrical or flat panels made of composite material with axial compression, inplane shear, and normal pressure.
19 citations
Patent•
20 Nov 1992
TL;DR: In this article, a structural composite panel is defined as a panel of the sandwich type composed of a core (10) made of thermoplastic material, the core being provided on its upper and lower faces with a skin (12, 12') made of reinforced thermoplastics material.
Abstract: Structural composite panel, characterised in that it comprises: - a panel of the sandwich type composed of a core (10) made of thermoplastic material, the core being provided on its upper and lower faces with a skin (12, 12') made of reinforced thermoplastic material; - a thin metal coating (16, 16') on at least one of the said faces of the sandwich panel and - a heat-sealable film (14, 14') inserted between the panel and each metal coating (16, 16'). The invention also relates to a method of manufacturing such a structural composite panel.
15 citations
Patent•
05 May 1992
TL;DR: In this paper, the inner and outer skin of a honeycomb structure panel is folded into a straight line and then the line is bent into a curve of the appropriate shape, such as an L-shape, a U-shape or a V-shape.
Abstract: The procedure consists of bending the inner and outer skins (6,9) of the panel to the appropriate shape before they are stuck to the layer of cellular material (8) between them.The inner skin (6) can be folded about a straight line (7), while the other one (9) is bent into a curve of the appropriate shape. The procedure can be used, for example, for honeycomb structure panels used in packaging or in furniture, and both the honeycomb layer and the inner and outer skins can be made from paper.The panel made by using the procedure can have a variety of shapes, including an L-shape, U-shape, V-shape or wavy. ADVANTAGE - Forms panels which are completely rigid, with excellent mechanical properties.
12 citations
TL;DR: In this article, a design diagram is proposed to enable direct reading of the desirable dimensions and the optimum weight relative to the referred material, and the results give some directions or recommendations on core properties for increasing the sandwich efficiency.
Abstract: Weight optimization of advanced sandwich composite using foam core is mainly highlighted in this paper. First, sandwich design criteria for most of the possible failure modes are presented in a systematic form that is convenient for the evaluation of the structural efficiency in direct comparison with referred materials to be substituted. A practical design diagram is then proposed to enable direct reading of the desirable dimensions, and the optimum weight relative to the referred material. Second, desirable performance of the core applicable in GFRP and/or CFRP sandwich supposed as the substitutions of steel and/or aluminum are studied by using the diagrams. The results give some directions or recommendations on core properties for increasing the sandwich efficiency. Regarding this core performance, the effect of foam density on the core mechanics is investigated and the optimum density to be managed are recommended.
10 citations
TL;DR: In this paper, the orientation of plies in a simply supported composite cylindrical panel is optimized to achieve the maximum buckling load in a repeated sublaminate construction, where the plies are used to avoid manufacturing errors and produce damagetolerant panels.
9 citations
Patent•
06 May 1992
TL;DR: In this paper, a glue of the reactive hot-melt type is applied to at least one end face (18) of the honeycomb core (10), and then a skin sheet (14) is placed under a light contact pressure onto that end face, and the temperature of the sandwich panel is adjusted to a value in the 120-160°C range, to melt the glue after which the sandwich is cooled down to the ambient temperature.
Abstract: Method for the manufacture of a sandwich panel comprising a honeycomb core (10) and a skin sheet (14) on both sides of the core, whereby a glue of the reactive hot-melt type is applied to at least one end face (18) of the honeycomb core (10), and whereby next a skin sheet (14) is placed under a light contact pressure onto that end face (18), the temperature of the sandwich panel is adjusted to a value in the 120-160°C range, to melt the glue after which the sandwich panel is cooled down to the ambient temperature.
8 citations
Patent•
18 Jun 1992
TL;DR: In this article, the authors proposed a method to prevent a honeycomb sandwich panel from being deformed and broken due to a slip of the outer periphery of honeycomb core at the manufacturing of the honeycomb panel under heat and pressure and lighten the weight of a product and apply the manufacturing method not only to flat surface but also to curved surface part.
Abstract: PURPOSE:To effectively prevent a honeycomb sandwich panel from being deformed and broken due to a slip of the outer periphery of honeycomb core at the manufacturing of the honeycomb sandwich panel under heat and pressure and lighten the weight of a product and apply the manufacturing method not only to flat surface but also to curved surface part. CONSTITUTION:A reinforcing member 9 is attached to the border on at least one open side of a honeycomb core 1, and surfacing materials 3a and 3b are attached to both of the sides of the honeycomb core. The honeycomb core is inserted in a flexible bag so as to seal the bag. The air in the flexible bag, in which the honeycomb core is inserted, is extracted. Under the above- mentioned condition, the bag is heated to a specified temperature under a predetermined pressure for a specified period of time.
01 Jan 1992
TL;DR: In this article, the combined load (compression and shear) equations were established for orthotropic sandwich panels by using the Rayleigh-Ritz method to minimize the panel total potential energy.
Abstract: The combined-load (compression and shear) buckling equations were established for orthotropic sandwich panels by using the Rayleigh-Ritz method to minimize the panel total potential energy. The resulting combined-load buckling equations were used to generate buckling interaction curves for super-plastically-formed/diffusion-bonded titanium truss-core sandwich panels and titanium honeycomb-core sandwich panels having the same specific weight. The relative combined-load buckling strengths of these two types of sandwich panels are compared with consideration of their sandwich orientations. For square and nearly square panels of both types, the combined load always induces symmetric buckling. As the panel aspect ratios increase, antisymmetric buckling will show up when the loading is shear-dominated combined loading. The square panel (either type) has the highest combined buckling strength, but the combined load buckling strength drops sharply as the panel aspect ratio increases. For square panels, the truss-core sandwich panel has higher compression-dominated load buckling strength. However, for shear dominated loading, the square honeycomb-core sandwich panel has higher shear-dominated combined load buckling strength.
Patent•
14 Apr 1992
TL;DR: In this paper, a ring-shaped notch 7 is formed to a sandwich panel by machining and the skin and core material of the part surrounded by the notch are crushed and an insert is inserted in said part and the periphery of the insert 3 is filled with a filler 4 and the filler 4 is cured to attach the insert3.
Abstract: PURPOSE:To prevent the damage of lightweight properties by suppressing an increase in the wt. of a filler even in a sandwich panel having large thickness by inserting an insert in a sandwich panel so as to crush the skin and core material of a part surrounded by a notch and filling the periphery of the insert with the filler to fix the insert. CONSTITUTION:A ring-shaped notch 7 is formed to a sandwich panel 1 by machining. Next, the skin 1f and core material 1g of the part surrounded by the ring-shaped notch 7 are crushed and an insert 3 is inserted in said part and the periphery of the insert 3 is filled with a filler 4 and the filler 4 is cured to attach the insert 3. The filler 4 in the periphery of the insert 3 attached to the sandwich panel 1 is interrupted by the skin if of the crushed part to be prevented from filling the core material 1a under the insert 3.
Patent•
06 Aug 1992
TL;DR: In this paper, a super-lightweight sandwich panel was constructed from unidirectional carbon fiber reinforced plastic, in which the fiber direction on the outsides is arranged to intersect perpendicularly to the fibre direction of the middle two layers, and bonding this skin to the surface of an Al honeycomb core with an epoxy adhesive.
Abstract: PURPOSE:To increase the flexural strength of a super-lightweight sandwich panel used to a solar cell of an artificial satellite by forming unidirectional carbon fiber reinforced plastics into a skin of four-layer structure, in which the fiber direction on the outsides is arranged to intersect perpendicularly to the fiber direction of the middle two layers, and bonding this skin to the surface of an Al honeycomb core CONSTITUTION:From unidirectional carbon fiber reinforced plastic a skin 1 is formed in foure-layers structure consisting of No1 layer 1a thru No4 layer 4d They are laminated in such an arrangement that the No1 and No4 layers 1a, 1d arelaid in a fiber direction of 0 deg, while the No2 and No3 layers 1b, 1c are in a fiber direction of 90 deg This skin 1 is bonded to the surface of an Al honeycomb core 2 with an epoxy adhesive 2 to yield a super-lightweight sandwich panel 1A
Patent•
09 Dec 1992
TL;DR: In this paper, a honeycomb sandwich panel with built-in heat pipes is constituted of two pieces of face sheets, honeycomb cores 3 held between the face sheets 2, a plurality of heat pipes 1 and an adhesive bonding them.
Abstract: PURPOSE: To lighten the weight of a honeycomb sandwich panel with built-in heat pipes wherein the same is used as a structural panel for loading the electronic apparatus of an artificial satellite and to contrive cost reduction. CONSTITUTION: A honeycomb sandwich panel with built in heat pipes is constituted of two pieces of face sheets 2, honeycomb cores 3 held between the face sheets 2, a plurality of heat pipes 1 and an adhesive bonding them. In the honeycomb sandwich panel, thin-walled fins 6 are provided in the corner parts formed of the heat pipes 1 and the face sheets 2. Thereby a filler is unnecessary between the heat pipes 1 and the honeycomb cores 3. COPYRIGHT: (C)1994,JPO&Japio
Patent•
25 Dec 1992
TL;DR: In this article, the authors proposed a method to prevent the lowering of durability caused by the deficiency of a resin and to enhance the adhesion of a honeycomb core member to surface plates by effectively preventing the penetration of the resin of the surface plates into the core member composed of a porous core material.
Abstract: PURPOSE: To prevent the lowering of durability caused by the deficiency of a resin and to enhance the adhesion of a honeycomb core member to surface plates by effectively preventing the penetration of the resin of the surface plates into the honeycomb core member composed of a porous core material. CONSTITUTION: Rubber layers 3 composed of a high mol. wt. rubbery material are provided to both surfaces of a honeycomb core member 2 obtained by forming a porous core material into a honeycomb shape along the opening end surfaces of honeycomb holes 2a and surface plates 4 composed of fiber reinforced plastic are integrally provided on the rubber layers 3. COPYRIGHT: (C)1994,JPO&Japio
Patent•
03 Apr 1992
TL;DR: In this paper, a sound-proofing sandwich panel including bituminous damping sheet, hard material and a hot-melt glue was used to achieve a softening point of 60 to 150 DEG C.
Abstract: Sound-proofing sandwich panel (1) including, on the lower face, a bituminous damping sheet (2) and, on the upper face, a layer of hard material (3) which is resistant at least up to 160 DEG C, assembled by means of a hot-melt glue (4) having a softening point of 60 to 150 DEG C.
Patent•
29 Jan 1992
TL;DR: In this paper, a monocock structure for a vehicle is formed by using honeycomb sandwich the honeycomb material 1 of which is formed of carbon fiber- reinforced plastic, fibers are orientated at a fiber angle 2 of + or -45 deg.
Abstract: PURPOSE:To provide a sandwich panel which is light and high in rigidity, especially torsional rigidity, by a method wherein a honeycomb forms a honeycomb sandwich formed of carbon fiber-reinforced plastic. CONSTITUTION:A monocock structure for a vehicle is formed by using honeycomb sandwich the honeycomb material 1 of which is formed of carbon fiber- reinforced plastic. In this case, in carbon fiber-reinforced plastic used for honeycomb, fibers are orientated at a fiber angle 2 of + or -45 deg. with the direction of the thickness of a sandwich panel. Formation of carbon fiber used for a honeycomb is preferably short fiber and when a fiber content is 20-40%-vol.%, a very thin resin-contained sheet can be easily manufactured. Further, when the carbon fiber-reinforced plastic is used for the surface material of a honeycomb structure, an effect of lightness is increased, an amount of energy absorbed during collision is high, structure maintaining capacity during the occurrence of a fire is also enhanced, and safety is improved.
Patent•
25 Mar 1992
TL;DR: In this article, a metal plate is installed positively with excellent appearance by also mounting the metal plate on the surface, side and setting up the plate to a foundation material in the connecting section of a pair of heat-insulating sandwich panels.
Abstract: PURPOSE:To install a metal plate positively with excellent appearance by also mounting the metal plate on the surface, side and setting up the metal plate to a foundation material in the connecting section of a pair of heat-insulating sandwich panels. CONSTITUTION:A bent section 9b is fitted into the fitting recessed groove 8 of fittings 9, a connecting section 9e is abutted against a packing 11, and an engaging section 9c is positioned along the underside of a fitting projecting section 6. A fixture 10 such as a machine screw is driven in from a mounting base section 9a under the state, and the mounting fittings 9 are fixed to the foundation material 4. The other heat-insulating sandwich panel A is placed on the foundation material 4, the end face of the other sandwich panel A is faced oppositely to the end face of one heat-insulating sandwich panel A through fittings 9, and the opposed fitting projecting section 6 and fitting recessed groove 8 are fitted while a recessed stepped section 5 and a fitting projecting piece 7 are fitted. The engaging section 9c is engaged with the fitting recessed groove 8 of the other heat-insulating sandwich panel A, and a pair of the heat-insulating sandwich panels A are connected while a pair of the heat-insulating sandwich panels A are installed to the foundation material 4.
Patent•
28 Sep 1992
TL;DR: In this paper, an embedding hole 3 is formed to a sandwich panel 1 having an embedded member 2 and consisting a core material 1a and skin materials 1b, 1c.
Abstract: PURPOSE:To obtain an extremely lightweight sandwich panel having an embedded member withstanding even a heat cycle test by providing the sandwich panel wherein skin materials made of carbon fiber reinforced plastic is laminated to both surfaces of a core material and an adhesive bonding the skin materials and the flange part of the embedded member. CONSTITUTION:An embedding hole 3 is formed to a sandwich panel 1 having an embedded member 2 and consisting a core material 1a and skin materials 1b, 1c. The insertion part 2a of the embedded member 2 formed from carbon fiber reinforced plastic of the same kind as the skin materials 1b, 1c is inserted in the embedding hole 3. The flange part 2b of the embedded member 2 is bonded to the skin material 1b of the sandwich panel 1 by an adhesive 4 to embed the embedded member 2 in the embedding hole 3. In the same way as a conventional one, the screw of other member is screwed in the screw hole 2c of the embedded member 2. Since the embedded member 2 and the skin materials 1b, 1c are made of a material of the same kind and same in the coefficient of linear expansion, no crack or release is generated even when the sandwich panel is subjected to a heat cycle test.
Patent•
02 Dec 1992
TL;DR: In this paper, a material obtained by folding a honeycomb laminated material having the same quality of material as core materials 1, 2 in the rectangular direction to the ribbon direction is installed between both core materials as a cushioning material 4.
Abstract: PURPOSE:To manufacture a sandwich panel having sufficient shearing strength by mounting a cushioning material between a core material and the core material or another structure member and joining the core material and the structure member. CONSTITUTION:A material obtained by folding a honeycomb laminated material having the same quality of material as core materials 1, 2 in the rectangular direction to the ribbon direction is installed between both core materials 1, 2 as a cushioning material 4. Sections among the cushioning material 4 and both core maerials 1, 2 are filled with foam adhesives 5. Sections near the bonding sections of the core materials 1, 2 or the wholes of the core materials 1, 2 are heated for curing foam adhesives 5. The foam adhesives 5 are foamed through heating, the clearances of the end sections of the honeycomb materials are buried with the adhesives 5, and the adhesives are cured at 120-180 deg.C and both core materials 1, 2 are joined. Accordingly, no crack is generated in joining sections, and strength, particularly shearing strength can be ensured in the same manner as core sections.
Patent•
14 Aug 1992
TL;DR: In this article, a cylindrical plug was used to reveal an orifice in a foam orifice, which was fitted into one of the metal sheets (21) of the sandwich panel (20) and the orifice was used in order to pass in the nozzle (24) with which the foam was injected.
Abstract: The plug possesses a cylindrical wall (2), a skirt (3) which is shorter than the cylindrical wall, a lip (5), a central wall (7) possessing a portion having pre-cutout areas defining tongues (tabs) (10) suitable for being bent inwards in order to reveal an orifice, and a cylindrical collar (11) which is connected internally to the central wall (7) on the perimeter of the said orifice. In the method, this plug is used by fitting it into one of the metal sheets (21) of the sandwich panel (20) and the orifice of the central wall (7) is used in order to pass in the nozzle (24) with which the foam (23) is injected.
Patent•
21 Oct 1992
TL;DR: In this paper, the authors proposed to prevent such a clearance as lowering the extent of strength and rigidity in a panel from occurring beneath a face sheet, by filling up a void between a fill tube of a heat pipe and a honeycomb core, in a honey-comb sandwich panel with the embedded heat pipe.
Abstract: PURPOSE:To prevent such a clearance as lowering the extent of strength and rigidity in a panel from occurring beneath a face sheet, by filling up a void between a fill tube of a heat pipe and a honeycomb core, in a honeycomb sandwich panel with the embedded heat pipe. CONSTITUTION:A metallic fill tube cover 1 is joined to a heat pipe plug or fill tube so as to cover a fill tube 3 of the heat pipe, and a void lying between the heat pipe and a honeycomb core is filled up.
Patent•
19 Feb 1992
TL;DR: In this paper, the authors proposed a method to obtain the title prepreg with good balance between mechanical strength, flame retardancy and low smoking by providing a polyvinyl alcohol layer on one or both of the surfaces of a thermosetting phenolic resin as impregnated resin.
Abstract: PURPOSE:To obtain the title prepreg with good balance between mechanical strength, flame retardancy and low smoking by providing a polyvinyl alcohol layer on one or both of the surfaces of a thermosetting phenolic resin as impregnated resin. CONSTITUTION:A fibrous cloth consisting of polyamide fiber, polyester fiber, etc., is impregnated with a thermosetting phenolic resin (e.g. novolak-type phenolic resin, resol-type phenolic resin) followed by drying, and one or both of the surfaces of the resin is(are) provided with polyvinyl alcohol layer (s) so as to be (on a solid basis) 10-40 pts.wt. based on 100 pts.wt. of said phenolic resin, thus obtaining the objective prepreg. The polyvinyl alcohol layer's) of the present prepreg is (are) laminated with honeycomb core(s) followed by bonding at 120-150 deg.C into the other objective sandwich panel.
Patent•
27 Oct 1992
TL;DR: In this paper, a thermosetting type synthetic rubber is held between the front end section 10 of a frame material 5 for mounting formed to the outer circumference of an external wall unit and the end section 8 of the surface board 2 of a honeycomb sandwich panel.
Abstract: PURPOSE: To simply execute a seal by forming an air- and water-tight seal section shaped of a vulcanized curable rubber between the end section of the surface board of a honeycomb sandwich panel and the front end section of a frame material. CONSTITUTION: A thermosetting type synthetic rubber is held between the front end section 10 of a frame material 5 for mounting formed to the outer circumference of an external wall unit 1 and the end section 8 of the surface board 2 of a honeycomb sandwich panel. The surface board 2 is heated and pressed by a hot press from the outside and the synthetic rubber is vulcanized and cured, and the front end section 10 and the end section 8 are bonded by a vulcanized curable rubber 7, thus forming an air- and water-tight seal section. COPYRIGHT: (C)1994,JPO&Japio
TL;DR: In this paper, an iterative method was developed for the steady-state temperature distribution in a two-dimensional rectangular sandwich panel fin heated within a rectangular footprint region, and dissipating energy to its environments as linearized radiation.
Abstract: An iterative calculation method is developed for the steady-state temperature distribution in a two-dimensional rectangular sandwich panel fin heated within a rectangular footprint region, and dissipating energy to its environments as linearized radiation. This method enables the temperature of each panel skin to be individually calculated by controlling mean skin temperatures under an energy balance constraint. The formulations derived approximate the typical satellite application in which a heat-generating electronic component is mounted on a equipment panel, such as an aluminum honeycomb sandwich panel. Comparison of numerical results obtained from the proposed method, and lumped nodal network analysis, shows that the proposed method will be useful for the evaluation of sandwich panel radiation fins in trade studies where geometrical configuration, heat loads, thermal properties, and environmental parameters change frequently. Nomenclature A = surface area, m2 b = width in Y direction, m F = configuration factor 2F = radiation interchange factor H = heat dissipation coefficient for linearized radiation, W/m2K h = heat transfer rate between skins of sandwich panel, W/m2K k = thermal conductivity, W/mK / = length in X direction, m q = heat flux, W/m2 T = temperature, K ti, t2 = thickness of inner and outer skin, m e = emissivity a = Stefan-Boltzmann constant, 5.67 x 10~ 8 W/m2K4
Journal Article•
TL;DR: In this article, the minimum weight is selected as an object function, as the weight critical structures are usually composed of these kind of construction, and the results are tabulated, which are calculated by using the nonlinear optimization technique SUMT.
Abstract: A sandwich element is a special Hybrid structural form of the composite construction, which is consisted of three main parts : thin, stiff and relatively high density faces separated by a thick, light, and weaker core material. In a sandwich construction, the shear deformation of the faces. Therefore, in the calculation of the bending stiffness, the shear effect should be included. In this paper, the minimum weight is selected as an object function, as the weight critical structures are usually composed of these kind of construction. To obtain the minimum weight of sandwich panel, the principle of minimum potential energy is used and as for the design constraints, the allowable bending stress of face material, the allowable shear stress of core material, the allowable value of panel deflection and the wrinkling stress of faces are adopted, as well as the different boundary conditions. For the engineering purpose of sandwich panel design, the results are tabulated, which are calculated by using the nonlinear optimization technique SUMT.
01 Sep 1992
TL;DR: In this article, an interactive finite element code was developed to predict bolted joint strength considering material and geometrical non-linearity, and the developed method conducts an ultimate strength failure analysis using a set of material degradation models.
Abstract: Non-linear analysis methods were adapted and incorporated in a finite element based DIAL code. These methods are necessary to evaluate the global response of a stiffened structure under combined in-plane and out-of-plane loading. These methods include the Arc Length method and target point analysis procedure. A new interface material model was implemented that can model elastic-plastic behavior of the bond adhesive. Direct application of this method is in skin/stiffener interface failure assessment. Addition of the AML (angle minus longitudinal or load) failure procedure and Hasin's failure criteria provides added capability in the failure predictions. Interactive Stiffened Panel Analysis modules were developed as interactive pre-and post-processors. Each module provides the means of performing self-initiated finite elements based analysis of primary structures such as a flat or curved stiffened panel; a corrugated flat sandwich panel; and a curved geodesic fuselage panel. This module brings finite element analysis into the design of composite structures without the requirement for the user to know much about the techniques and procedures needed to actually perform a finite element analysis from scratch. An interactive finite element code was developed to predict bolted joint strength considering material and geometrical non-linearity. The developed method conducts an ultimate strength failure analysis using a set of material degradation models.
TL;DR: In this article, a foundation wall is constructed by assembling lightweight sandwich panels without a crane, then pouring lightweight concrete fill between the panels and surrounding excavation, which is useful for soils cohesive enough to support a vertical cut until the fill is placed.
Abstract: Foundation walls have been formed by assembling lightweight sandwich panels without a crane, then pouring lightweight concrete fill between the panels and surrounding excavation. The wet fill exerts low pressure on the panels because it weighs less than 50 lb/cu ft and is poured in two lifts. The first lift is hardened with an accelerator before the second lift is poured. The hardened fill stiffens the panels against subsequent earth pressure. The method is useful for soils cohesive enough to support a vertical cut until the fill is placed. Construction is illustrated using mesh‐reinforced mortar‐faced polystyrene foam‐core sandwich panels and backfill containing fly ash and recycled polystyrene foam aggregate. Design examples use laboratory test values and illustrate the calculation of minimum‐cost thicknesses of sandwich panel and fill for required bending stiffness.