Ultrasonic-assisted friction drilling process of aerospace aluminum alloy (AA7075): FEA and experimental study

Joining sheets and plates in the industry is of high importance. In the automotive and aerospace industry, using friction drilling technique is developing. In order to improve this method, different techniques have been used. In this research, applying ultrasonic vibration on the tool will be investigated. In this regard, a special tool was designed. Axial force and surface hardness were measured in friction drilling and ultrasonic assisted friction drilling. Higher rotational speed and lower feed rate induce lower axial force and higher surface hardness. In addition, ultrasonic vibration causes the surface to be harder with lower axial force. The results show that increasing the rotational speed and decreasing the feed rate in lathe machine causes axial force reduction and surface hardness increase in heat affect zone and thermomechanical region. Moreover, finite element method was carried out which indicated lower axial force occurs in ultrasonic assisted friction drilling comparing to conventional condition. Equivalent plastic strain was used to examine hardness value numerically. The obtained numerical and experiment results were in good agreement

Residual stress in engineering materials: a review

The accurate determination of residual stresses has a crucial role in understanding the complex interactions between microstructure, mechanical state, mode(s) of failure, and structural integrity. Moreover, the residual stress management concept contributes to industrial applications, aiming to improve the product's service performance and life cycle. In this regard, the industry requests rapid, efficient, and modern methods to identify and control the residual stress state. This review article contains three main sections. The first section covers different residual stress determination methods and reports the advancements over the recent decade. The second section includes the role of residual stresses in the performance of a broad range of materials including metallic alloys, polymers, ceramics, composites, and biomaterials. This is presented by classifying different science areas dealing with residual stresses into two main groups, including “origins” and “effects” of residual stresses. The range of topics covered are “welding, machining, curing/cooling, and spray coating processes,” “medical and dental sciences,” and “fatigue and fracture mechanisms.” The third section summarizes various strategies to effectively control residual stresses through different manufacturing procedures. It is hoped that the data provided herein serves as a valuable up-to-date reference for engineers and scientists in the field of residual stress