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Sowing is one of the important operations in agriculture which requires accuracy, timeliness and skilled labour. Majority of Indian farmers still follow traditional manual method of sowing due to various reasons. Considering the requirement of farmers with small land holding and variety of crops grown it is required to develop a compact, and economical sowing machine. Literature survey, filed visits and data collection from stakeholders revealed the need for development of semi-automated sowing machine for major crops; Groundnut, Maize, Sunflower and Toor dal cultivated throughout the year, thus justifies the capital investment. Adopting the first principles of engineering design, a semi-automated sowing machine was designed, synthesized and fabricated. The machine consists of three subsystems; power system, traction system, seed metering system. The machine is walk-behind vehicle that can carry out sowing operation in three rows simultaneously. The developed sowing machine has been tested for its working and found to be satisfactory. The estimated reduction in cost of sowing is found to be in the range of 80–85% apart from reducing the time involved in sowing operation.

Elongated holes are found in many aerospace structural components and are prone to fatigue failure due to the stress concentration effect at the edge of the hole. Different approaches like shape reworking, shape optimization, and cold expansion combined with interference fitting are currently used as a repair/life extension option, to overcome fatigue cracking problems around elongated holes. In practice, these approaches lead to either addition of material or modification of geometry. A novel and economical method derived from renowned hole cold expansion process is proposed in the literature to enhance the fatigue life of elongated hole without adding material and modifying hole geometries. Benefit of implementing proposed novel cold expansion method for elongated hole is investigated in this work through a simplified three-dimensional nonlinear Finite Element simulation. Distributions of induced beneficial residual stress around and along the thickness direction of elongated hole are predicted from the FE simulation. The results indicate introduction of significant beneficial residual stresses throughout the thickness surface of elongated hole. These beneficial residual stresses are responsible for fatigue life extension and can be further used to quantify the achieved fatigue life enhancement.

Presence of a neighboring hole introduces limits on the level of expansion that can be applied during cold expansion of adjacent holes. Particularly in case of closely spaced holes, it is required to consider the effect of proximity hole in arriving at optimum cold expansion level. The present work is aimed at assessing the effect of neighboring hole on induced residual stresses during cold expansion of adjacent holes through finite element simulation. Four different situations of cold expansion of adjacent holes including a proposed novel approach are considered to obtain detailed insight into the extent of residual stresses induced. The proposed novel approach suggests insertion of a rigid pin into the neighboring hole during cold expansion. This effect has been incorporated during simulation of cold expansion. The simulation results show higher values of residual stresses induced and consequently, larger fatigue life enhancement benefits are expected through the proposed novel approach.

Various methods to induce beneficial residual stresses through controlled mechanical working on the surface of mechanical components are used to improve their fatigue life. Low Plasticity Burnishing (LPB) is one such technique gaining popularity compared to other similar technique due to the advantage of improving fatigue life without changing material and component design. Application of LPB to a specific component necessitates simulation of the process and evaluation of process parameters to get an insight into the depth, magnitude and distribution of induced beneficial residual stresses. Present work is an attempt to simulate ball indentation to evaluate process parameters and LPB simulation to predict induced beneficial stresses on the work piece surface. This simulation is used to evaluate the LPB induced residual stress distributions on the components made two different materials (Al 2024-T351 and Al 7075-7651) and three different indentation depths. Effect of different LPB process parameters on residual stress distributions are obtained from the FE simulations. The developed FE framework for simulation of indentation is further extended to adequately simulate LPB process to predict induced residual stresses.The evaluated residual stresses are useful for predicting fatigue life enhancement benefits derived from LPB.

Fatigue damage is one of the most prevalent failures around fastener holes of aircraft structures. The fatigue resistance of fastener holes is routinely enhanced through Split-Sleeve Cold Expansion. The extent of fatigue life improvement due to cold expansion depends on induced residual compressive stresses. In this work, a series of FE simulations were carried out for various levels of cold expansions around a hole in Al2024-T3 flat plate to analyze induced residual stresses. The improvement in fatigue performance due to induced residual stresses is predicted using Goodman’s theory and can be incorporated to achieve optimal designsof aircraft fastener joints.

Cold expansion process is widely used to enhance fatigue life of fastener holes in aircraft industry. The benefit derived from cold expansion treatment is attributed to residual stresses induced around hole. This work is aimed at establishing a simple procedure for predicting Fatigue Crack Growth (FCG) life around cold expanded holes. Cold expansion process is simulated for uncracked and cracked holes using Finite Element method. The effect of residual stresses is accounted to predict FCG life using Willenborg's model. As a result of cold expansion, significant retardation in FCG rate and life improvement is achieved.

Cold expansion technique is a mechanical method of inducing beneficial compressive stresses around circular holes to offset the applied tensile stress resulting in improved fatigue life. The beneficial effect derived from the cold expansion process is entirely dependent on the magnitude and distribution of the induced residual stresses around the hole. In the present work a 3-D finite element simulation of cold expansion of a circular hole has been developed employing a new approach. In this approach, expansion is simulated by enlarging the hole layer by layer successively from one side of the plate to the other side resulting in simulation of gradual and complete expansion of the hole in the first stage. This process is followed by removal of applied boundary conditions again layer by layer resulting in gradual spring back of the hole completing the simulation of cold expansion process in the second stage. The present approach is capable of capturing the variation of residual stresses at various sections along the thickness as it happens in the actual split sleeve cold expansion process. The results in terms of the residual stress distribution and its variation along the thickness are presented, compared and found to be in close agreement with the published data.