Passive-adaptive indentor for stress wave cold working

A passive-adaptive indentor for cold working a material, the material including a material surface and a depth extending in a direction that is perpendicular to a direction of the material surface, comprising:

• a first member comprising a first working end and being configured to create a first residual stress field that extends to a predetermined depth in the material;
• and
• a second member comprising a second working end and being configured to create a second residual stress field that extends to a generally fixed second depth of the material regardless of the depth to which the first residual stress field extends,
• wherein the first member comprises a shaft terminating in the first working end which terminates in an end surface;
• and
• wherein the second member comprises a tubular structure terminating in the second working end, the second working end comprising a shoulder surface and wherein the tubular structure is dimensioned and configured to be in a co-axial relationship with the shaft and be movable along an axial direction of the shaft,
• a housing comprising a cavity defined by an inner surface, the housing being in fixed relationship with the shaft,
• an elastic deformation and rebound element which is disposed within the cavity so that the element is interposed between the inner surface of the housing and the movable tubular structure and positioned on a surface of the tubular structure and which is suitable for providing resilient reciprocal spring action for providing a resilient cushion for the tubular structure,
• wherein the tubular structure comprises a collar and a radially extending portion and wherein the elastic deformation and rebound element is disposed between the inner surface of the cavity and a surface of the radially extending portion,
• wherein the elastic deformation and rebound element comprises an assembly arrangement of conical disc spring members.

A passive-adaptive indentor for cold working a material, the material including a material surface and a depth extending in a direction that is perpendicular to a direction of the material surface, comprising:

• a first member comprising a first working end and being configured to create a first residual stress field that extends to a first predetermined depth in the material, the first member being subjected to a first force whereby the first working end strikes the material surface at a force sufficient to create the first residual stress field;
• and
• a second member being disposed in slidable relationship with the first member and comprising a second working end, the second member being configured to create a second residual stress field that extends to a generally fixed second depth of the material, regardless of the depth at which the first residual stress field extends, the second member being subjected to a second force whereby the second working end strikes the material surface at a force sufficient to create the second residual stress field,
• wherein the first member comprises a shaft terminating in the first working end which comprises an end surface,
• the second member comprises a tubular structure terminating in the second working end, the second working end comprising a shoulder surface and wherein the tubular structure is dimensioned and configured to be in a co-axial relationship with the shaft and be movable along an axial direction of the shaft,
• a housing having a cavity defined by an inner surface and an opening, the housing being in fixed relationship with the shaft which extends within the cavity and through the opening, the tubular structure also extending through the opening,
• an elastic deformation and rebound element disposed within the cavity and positioned on a surface of the radially extending portion of the tubular structure and between the inner surface of the cavity and a second surface of the radially extending portion of the tubular structure;
• and
• wherein the elastic deformation and rebound element comprises an assembly arrangement of conical disc spring members.

A passive-adaptive indentor for cold working a material, the material comprising an aerospace structure having a planar material including a planar material faying surface, a support member having a support member faying surface and a joint located at a contact portion of the planar material faying surface and the support member faying surface, the planar material including a planar material surface and a depth extending in a direction that is perpendicular to a direction of the planar material surface, comprising:

• a first member being configured to create a first residual stress field in the material that extends to the joint upon being subjected to a first force so that the first working end strikes the planar material surface at a force sufficient to create the first residual stress field and the first member comprising a shaft terminating in a first working end which comprises an end surface;
• a second member being configured for being subjected to a second force so that the second working end strikes the planar material surface at a force sufficient to create a second residual stress field that extends to a depth that is in variable predetermined proportion to that of the first residual stress field and wherein the second member comprises a tubular structure which terminates in a second working end that comprises a shoulder surface and wherein the tubular structure is dimensioned and configured to be in a co-axial relationship with the shaft and be movable along an axial direction of the shaft, the tubular structure also comprising a collar and a radially extending portion;
• a housing having a cavity defined by an inner surface and an opening, the housing being in fixed relationship with the shaft which extends within the cavity and through the opening, the tubular structure also extending through the opening;
• and
• an elastic deformation and rebound element which is positioned on a surface of the second member and disposed between the inner surface of the cavity and the collar and which is configured to produce the second force and is further suitable for providing resilient reciprocal spring action for providing a resilient cushion for the tubular structure.

A method of cold working a material using a passive-adaptive indentor to create plural stress fields in the material and that is capable of automatically varying a depth at which a first stress field is to extend while a second stress field extends to a second predetermined depth in the material, the material including a material surface, a depth extending in a direction that is perpendicular to a direction of the material surface, the method comprising the steps of:

• providing a material having multiple locations to be cold worked;
• identifying a first location and a particular depth of interest to which a first stress field is to extend at the first location;
• identifying a particular force to apply to a passive-adaptive indentor depending upon the particular depth of interest;
• applying the particular force only to a first member of the first passive-adaptive indentor to simultaneously create a first residual stress field that extends to the particular depth of interest and a second residual stress field that extends to a second predetermined depth, the second predetermined depth being proportional to the first predetermined depth, wherein the second predetermined depth varies a predetermined proportion to the first predetermined depth;
• and moving the passive-adaptive indentor to another location.