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Gasket sealability test techniques are used to characterize gasket material properties as they relate to sealing performance. Increasing use of coated metal gasket materials with formed sealing features extends this test method to also characterize the influence of gasket design features known as embosses or beads. The essence of gasket sealability test methods involves compressing the gasket specimen between flat and presumably parallel surfaces of the test platens. This paper explores the effects of platen parallelism on sealability test results. Initial investigations have revealed platen parallelism has a significant effect on observed test results with certain gasket materials. The primary focus of this work involves rigidly mounted platens as opposed to spherically mounted, or wobble platens. Techniques for evaluating the rotational bending stiffness of platen and loading fixture configurations are also presented.

Gasketed bolted joint analysis tools are gaining importance as the market place demands superior product performance, reduced cycle time, and lower cost. Design analysis tools can be used to predict product performance over the life of the joint. Numerous design concepts under a range of operating conditions can be simulated. The optimal designs can be determined before a prototype is manufactured and tested. The reduction in prototyping and testing results in cost savings and a reduction in design time. The customer is provided with a product with superior sealing performance at a lower cost. This paper presents a design analysis technique which uses a non-linear finite element program in conjunction with a spreadsheet. The spreadsheet functions as a user friendly input and output interface to the finite element program. Parametric models are used to define the geometry of standard sealing system components that include gaskets, flanges, and fasteners.

Many gaskets have constructions that combine structures of varying compressive stiffness. Low stiffness features may be used for coolant and oil seals; while, extremely stiff components could be used around a fastener as a load stop or around a combustion opening as part of a combustion seal. The use of a high stiffness stopper as part of a combustion seal has a significant effect on the overall behavior of the gasket. The stopper influences the distribution of total bolt load over the entire gasket by concentrating load toward the combustion opening. In the case of multi-layer steel gaskets, fluctuating loads on the combustion seal such as the head lifting force that is generated from the cylinder firing pressure are split between high stiffness stoppers and lower stiffness embosses that surround the combustion opening. In this paper, we will look at the basic mechanics of combustion seal stoppers and consider the effect of the stopper on combustion seal performance.

An embossed single layer of rubber coated metal is a technology that is being applied to the sealing of gasketed joints in internal combustion engines. This technology has the stability of steel, the sealability of rubber, and the control of stiffness through emboss geometry. The sealing performance of this technology is a function of many parameters involving material properties, gasket geometry, surface finish, and joint loading. The relationship between coolant sealability and these parameters was measured. In this paper, results are presented for half emboss configurations where emboss height, surface finish, and clamp load are varied. The data shows that emboss height and flange surface roughness have little effect on the sealing performance of the material studied. The data can be used to select gasket designs which require less expensive flange finishes and lower assembly loads while providing good sealing performance.