Anchoring in a lightweight building element

A method of anchoring a connector in a heterogeneous first object comprising a first building layer and, distally of the first building layer, an interlining layer, wherein the interlining layer has a density substantially lower than a density of the first building layer and/or a mechanical stability substantially lower than a mechanical stability of the first building layer, the method comprising the steps of

• providing the first object;
• providing the connector that comprises thermoplastic material in a solid state and extends between a proximal end and a distal end;
• bringing the connector into physical contact with the first building layer;
• applying a first mechanical pressing force and mechanical vibration to the connector until the first building layer is pierced by the connector in a vibration assisted manner, and a distal portion of the connector reaches into the interlining layer;
• applying a second mechanical pressing force and mechanical vibration to the connector until a flow portion of the thermoplastic material is flowable and penetrates structures of the first object, and
• stopping the second mechanical vibration and letting the thermoplastic material resolidify to yield a positive-fit connection between the connector and the first object.