Abstract: A method of resistance spot welding a workpiece stack-up that includes a steel workpiece and an aluminum workpiece includes adhering an aluminum patch to faying surface of a steel workpiece, positioning an aluminum workpiece over the aluminum patch and the steel workpiece to assemble a workpiece stack-up, passing an electric current through the workpiece stack-up to create a molten aluminum weld pool, and terminating passage of the electric current to solidify the molten aluminum weld pool into a weld joint that bonds the steel and aluminum workpieces together through the aluminum patch. A workpiece stack-up having a weld joint that bonds an aluminum workpiece and a steel workpiece together through an aluminum patch is also disclosed. The weld joint establishes a bonding interface with the faying surface of the steel workpiece, and the aluminum patch is adhered to the faying surface of the steel workpiece around the weld joint.

Abstract: A combined stackup apparatus with a perforated interlayer for resistance spot welding is provided. The apparatus comprises a first metal sheet of a first material and a second metal sheet of a second material. The apparatus further comprising a perforated interlayer disposed between the first metal layer and the second metal layer. The perforated interlayer is made of one of the first and second materials. The perforated interlayer has a plurality of perforations formed therethrough. Each perforation has a perforation size of between about 0.1 mm and about 3 mm.

Abstract: A method of resistance spot welding a stacked assembly of dissimilar workpieces. The stack assembly includes a first workpiece formed of a first alloy, a second workpiece formed of a second alloy, and a third workpiece formed of a third alloy sandwiched between the first workpiece and the second workpiece. The third alloy includes a lower resistivity than the first alloy and a lower resistivity than the second alloy. A faying interface is defined by a portion of the first workpiece in direct contact with a portion of the second workpiece through the third workpiece. A weld nugget, a braze, or a combination of a weld nugget and a braze joins the first workpiece to the second workpiece at the faying interface. An annular ring of re-solidified molten pool of third alloy surrounds the faying interface and a region of re-solidified partially melted third alloy surrounding the annular ring.

Abstract: A method of resistance spot welding a stacked assembly of dissimilar workpieces. The stack assembly includes a first workpiece formed of a first alloy, a second workpiece formed of a second alloy, and a third workpiece formed of a third alloy sandwiched between the first workpiece and the second workpiece. The third alloy includes a lower resistivity than the first alloy and a lower resistivity than the second alloy. A faying interface is defined by a portion of the first workpiece in direct contact with a portion of the second workpiece through the third workpiece. A weld nugget, a braze, or a combination of a weld nugget and a braze joins the first workpiece to the second workpiece at the faying interface. An annular ring of re-solidified molten pool of third alloy surrounds the faying interface and a region of re-solidified partially melted third alloy surrounding the annular ring.

Abstract: A method to join three panels together for a motor vehicle includes one or more of the following: layering the three panels, the three panels including a first panel, a second panel, and a third panel, the second panel being positioned between the first panel and the third panel, the third panel having a higher electrical conductivity than the first panel and the second panel; joining the first panel and the second panel together; and joining the third panel to the first panel and the second panel.

Abstract: An electrical resistance spot welding electrode is disclosed for contact with a narrow or other selected spot weld region in a steel workpiece in a stack-up with an aluminum alloy workpiece for use in a spot welding method in which the weld nugget is carefully formed in the aluminum workpiece at the interface of the stack-up. The welding face of the welding electrode for contact with the steel workpiece is shaped with an aspect ratio greater than one, which fits against the contact surface of the steel workpiece, while the welding face for the aluminum-contacting weld electrode is circular (with an aspect ratio equal to one). The stack-up of workpieces may include a single steel workpiece facing two aluminum workpieces in a sandwich type stack-up or two steel workpieces facing a single aluminum workpiece with the outer steel workpiece having the narrow contact surface for the steel welding electrode.

Abstract: A combined stackup apparatus with a perforated interlayer for resistance spot welding is provided. The apparatus comprises a first metal sheet of a first material and a second metal sheet of a second material. The apparatus further comprising a perforated interlayer disposed between the first metal layer and the second metal layer. The perforated interlayer is made of one of the first and second materials. The perforated interlayer has a plurality of perforations formed therethrough. Each perforation has a perforation size of between about 0.1 mm and about 3 mm.

Abstract: A welding electrode includes a weld face that has a convex base weld face surface and a plurality of ringed ridges that are radially spaced apart on the base weld face surface and surround a central weld face axis. The plurality of ringed ridges including an innermost ringed ridge and an outermost ringed ridge. The innermost ringed ridge is located closest to the central weld face axis and rises above a central portion of the base weld face surface, and the outermost ringed ridge is located farthest from the central weld face axis and rises above an outer peripheral portion of the base weld face surface. At least one of the plurality of ringed ridges is a discontinuous ringed ridge.

Abstract: A probe for detecting discontinuities includes: a body portion; a head portion; one or more inductor coils located in the head portion and configured to: receive power from a power source; when power is received, induce an eddy current in a joint where a first metal component is joined with a second metal component; based on the induced eddy current, output a signal indicative of an inductance of the one or more inductor coils; and a plurality of positioning devices configured to maintain the one or more inductor coils approximately a predetermined distance from the surface.

Abstract: A method of resistance spot welding a workpiece stack-up that includes a steel workpiece and one or more aluminum workpieces involves locally stiffening the steel workpiece to resist steel workpiece deformation. The local stiffening of the steel workpiece is achieved by incorporating an electrode receiving wall into the steel workpiece along with one or more integral elevated portions of the steel workpiece that are disposed at least partially around the electrode receiving wall. The electrode receiving wall includes an electrode-contact surface and an opposed interface contact surface. During welding, a weld face of one welding electrode is pressed against the electrode-contact surface of the electrode receiving wall of the steel workpiece, and electric current is momentarily passed between that welding electrode and another welding electrode on the opposite side of the workpiece stack-up to form a weld joint that bonds to the interface contact surface of the electrode receiving wall.

Abstract: A method of resistance spot welding a workpiece stack-up that includes an aluminum workpiece and an overlapping adjacent steel workpiece so as to minimize the thickness of an intermetallic layer comprising Fe—Al intermetallic compounds involves providing reaction-slowing elements at the faying interface of the aluminum and steel workpieces. The reaction-slowing elements may include at least one of carbon, copper, silicon, nickel, manganese, cobalt, or chromium. Various ways are available for making the one or more reaction-slowing elements available at the faying interface of the aluminum and steel workpieces including being dissolved in a high strength steel or being present in an interlayer that may take on a variety of forms including a rigid shim, a flexible foil, a deposited layer adhered to and metallurgically bonded with a faying surface of the steel workpiece, or an interadjacent organic material layer that includes particles containing the reaction-slowing elements.

Abstract: A welding electrode and a method of using the welding electrode for resistance spot welding are disclosed. The welding electrode includes a body and a weld face. The weld face includes a central dome portion and a shoulder portion that surrounds the central dome portion and extends from an outer circumference of the weld face upwardly and radially inwardly to the central dome portion. The central dome portion has a series of radially-spaced ringed ridges that project outwardly from a base dome face surface. The series of radially-spaced ringed ridges on the central dome portion includes an innermost ringed ridge and an outermost ringed ridge. The outermost ringed ridge on the central dome portion has a radial inner side surface and a radial outer side surface. The radial outer side surface extends below the base dome face surface down to the shoulder portion of the weld face.

Abstract: An occupant support structure and a method of customizing an occupant support structure. The occupant support structure may comprise a base and a reconfigurable cushion carried by the base. The reconfigurable cushion may include an occupant support surface and a bladder. The bladder may include an outer wall that defines an inner cavity underlying the occupant support surface and two or more overlapping material layers disposed within the cavity. The overlapping material layers may be adapted to selectively transition from a compliant state to a rigid state and vice versa by selective control of a pressure condition across the outer wall of the bladder to reconfigure or conform the occupant support surface of the cushion to a contour of a portion of an occupant supported by the cushion.

Abstract: A method of resistance spot welding a workpiece stack-up that includes a steel workpiece and an aluminum workpiece includes adhering an aluminum patch to faying surface of a steel workpiece, positioning an aluminum workpiece over the aluminum patch and the steel workpiece to assemble a workpiece stack-up, passing an electric current through the workpiece stack-up to create a molten aluminum weld pool, and terminating passage of the electric current to solidify the molten aluminum weld pool into a weld joint that bonds the steel and aluminum workpieces together through the aluminum patch. A workpiece stack-up having a weld joint that bonds an aluminum workpiece and a steel workpiece together through an aluminum patch is also disclosed. The weld joint establishes a bonding interface with the faying surface of the steel workpiece, and the aluminum patch is adhered to the faying surface of the steel workpiece around the weld joint.

Abstract: An electrical resistance spot welding electrode is disclosed for contact with a narrow or other selected spot weld region in a steel workpiece in a stack-up with an aluminum alloy workpiece for use in a spot welding method in which the weld nugget is carefully formed in the aluminum workpiece at the interface of the stack-up. The welding face of the welding electrode for contact with the steel workpiece is shaped with an aspect ratio greater than one, which fits against the contact surface of the steel workpiece, while the welding face for the aluminum-contacting weld electrode is circular (with an aspect ratio equal to one). The stack-up of workpieces may include a single steel workpiece facing two aluminum workpieces in a sandwich type stack-up or two steel workpieces facing a single aluminum workpiece with the outer steel workpiece having the narrow contact surface for the steel welding electrode.

Abstract: A method of resistance spot welding and a spot-welded workpiece assembly are provided. First and second metallic workpieces are provided, each having faying surfaces including interface portions. The workpieces are disposed with the interface portions of their faying interfaces spaced apart from each other by a predetermined spacing distance. A set of opposed welding electrodes including a first electrode and a second electrode are provided, the first electrode being disposed on a side of the first workpiece, and the second electrode being disposed on a side of the second workpiece. Pressure is applied to the workpieces via the weld faces of the electrodes, and the workpieces are heated via the electrodes to form a spot weld joint between the interfaces of the faying surfaces. The faying surfaces may be spaced apart with shim material, a raised or folded-over portion of a workpiece, and/or a filler material having spacing particles.

Abstract: A stretchable adjustable-stiffness assembly includes a casing and first and second friction layers. The casing can be fluidly sealed and includes an interior compartment containing a fluid. The fluid can shift between a first interior pressure and a second interior pressure less than the first interior pressure and an exterior pressure. The first and second friction layers are disposed within the interior compartment. The assembly can shift between relaxed and fixed configurations. In the relaxed configuration, the fluid has the first interior pressure, the casing is stretchable between a first dimension and a second dimension greater than the first dimension, and the assembly has a first stiffness. In the fixed configuration, the first fluid has the second interior pressure, the casing length is fixed, the first and second friction layers are engaged, and the assembly has a second stiffness greater than the first stiffness.

Abstract: A method of resistance spot welding is provided that includes overlapping weld joints. The method may be used to repair a discrepant weld joint or to strengthen a weld joint. Pressure and electrical current is initially applied to workpieces via weld faces of electrodes to form an initial spot weld joint attempt between the first and second workpieces, and then the initial application of pressure is removed. A subsequent application of pressure and electrical current is then applied to the workpieces via the weld faces to form an overlapping spot weld joint between the first and second workpieces. The overlapping spot weld joint overlaps with the initial spot weld joint attempt. The initial spot weld joint attempt may be successful or not, such that the overlapping weld joint either repairs or strengthens the initial weld joint attempt. Overlap of the welds may be 10-100%.

Abstract: A method of resistance spot welding a workpiece stack-up that includes a steel workpiece and one or more aluminum workpieces involves locally stiffening the steel workpiece to resist steel workpiece deformation. The local stiffening of the steel workpiece is achieved by incorporating an electrode receiving wall into the steel workpiece along with one or more integral elevated portions of the steel workpiece that are disposed at least partially around the electrode receiving wall. The electrode receiving wall includes an electrode-contact surface and an opposed interface contact surface. During welding, a weld face of one welding electrode is pressed against the electrode-contact surface of the electrode receiving wall of the steel workpiece, and electric current is momentarily passed between that welding electrode and another welding electrode on the opposite side of the workpiece stack-up to form a weld joint that bonds to the interface contact surface of the electrode receiving wall.

Abstract: A welding electrode and a method of using the welding electrode for resistance spot welding are disclosed. The welding electrode includes a body and a weld face. The weld face includes a central dome portion and a shoulder portion that surrounds the central dome portion and extends from an outer circumference of the weld face upwardly and radially inwardly to the central dome portion. The central dome portion has a series of radially-spaced ringed ridges that project outwardly from a base dome face surface. The series of radially-spaced ringed ridges on the central dome portion includes an innermost ringed ridge and an outermost ringed ridge. The outermost ringed ridge on the central dome portion has a radial inner side surface and a radial outer side surface. The radial outer side surface extends below the base dome face surface down to the shoulder portion of the weld face.