Abstract: A method for joining two aircraft structural parts by a bolted or riveted joint and for preventing cracks at said joint includes providing a first metallic aircraft structural part and a second aircraft structural part, wherein the first aircraft structural part includes a first joint region and a second aircraft structural part includes a second joint region. Furthermore, the method includes inducing compressive residual stresses in a first area of the first joint region for preventing cracks by applying parallel crack retarding regions formed as stripes in the first area, drilling fastener holes in the first and second areas of the first. Finally, the method includes a step of fastening together the first and second aircraft structural parts at the first and second joint regions by a bolted or riveted joint.

Abstract: A method for joining two aircraft structural parts by a bolted or riveted joint and for preventing cracks at said joint includes a step of providing a first metallic aircraft structural part and a second aircraft structural part, wherein the first aircraft structural part includes a first joint region and a second aircraft structural part includes a second joint region. Furthermore, the method includes a step of inducing compressive residual stresses in a first area of the first joint region for preventing cracks. Finally, the method includes a step of fastening together the first and second aircraft structural parts at the first and second joint regions by a bolted or riveted joint. An aircraft including first and second aircraft structural parts is also described.

Abstract: The present invention provides a method for preventing the forming of cracks and slowing the crack propagation in metallic airplane structural parts by laser shock peening with the following steps: Providing an airplane structural part having a crack; irradiating a first surface area of the airplane structural part close to the crack with a first pulsed laser beam having a first wavelength and a first pulsation frequency, wherein energy of the first laser beam is absorbed by the airplane structural part and a shock wave runs through the airplane structural part, which creates compressive prestressings in the airplane structural part.

Abstract: A structural element for reinforcing a fuselage cell of an aircraft is provided. The structural element comprises a reinforcement profile which is made in one piece from a metallic material. The profile is provided with a strap at least in regions. As a result of the strap which is made of a fiber-reinforced layer material or fiber metal laminate and is adhesively bonded, at least in regions, to a flange of the reinforcement profile the structural element has high damage tolerance and advantageous fatigue properties. The fiber metal laminate or layer material is made of a plurality of metal layers and fiber-reinforced plastics material layers which are stacked in alternating fashion and adhesively bonded to one another over the entire surface. The reinforcement profile and the strap are joined by means of a joining layer. Said joining layer is preferably constructed from two prepreg layers and a non-fiber-reinforced adhesive layer.

Abstract: The present invention provides a method for preventing the forming of cracks and slowing the crack propagation in metallic airplane structural parts by laser shock peening with the following steps: Providing an airplane structural part having a crack; irradiating a first surface area of the airplane structural part close to the crack with a first pulsed laser beam having a first wavelength and a first pulsation frequency, wherein energy of the first laser beam is absorbed by the airplane structural part and a shock wave runs through the airplane structural part, which creates compressive prestressings in the airplane structural part.

Abstract: A structural element for reinforcing a fuselage cell of an aircraft is provided. The structural element comprises a reinforcement profile which is made in one piece from a metallic material. The profile is provided with a strap at least in regions. As a result of the strap which is made of a fibre-reinforced layer material or fibre metal laminate and is adhesively bonded, at least in regions, to a flange of the reinforcement profile the structural element has high damage tolerance and advantageous fatigue properties. The fibre metal laminate or layer material is made of a plurality of metal layers and fibre-reinforced plastics material layers which are stacked in alternating fashion and adhesively bonded to one another over the entire surface. The reinforcement profile and the strap are joined by means of a joining layer. Said joining layer is preferably constructed from two prepreg layers and a non-fibre-reinforced adhesive layer.