Yazar "Danquah, Josiah Owusu" seçeneğine göre listele

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    Additively Manufactured Custom Soft Gripper with Embedded Soft Force Sensors for an Industrial Robot
    (Korean Soc Precision Eng, 2021) Dilibal, Savas; Sahin, Haydar; Danquah, Josiah Owusu; Emon, Md Omar Faruk; Choi, Jae-Won
    Soft robotic grippers are required for power grasping of objects without inducing damage. Additive manufacturing can be used to produce custom-made grippers for industrial robots, in which soft joints and links are additively manufactured. In this study, a monoblock soft robotic gripper having three geometrically gradient fingers with soft sensors was designed and additively manufactured for the power grasping of spherical objects. The monoblock structure design reduces the number of components to be assembled for the soft gripper, and the gripper is designed with a single cavity to enable bending by the application of pneumatic pressure, which is required for the desired actuation. Finite element analysis (FEA) using a hyperelastic material model was performed to simulate the actuation. A material extrusion process using a thermoplastic polyurethane (TPU) was used to manufacture the designed gripper. Soft sensors were produced by a screen printing process that uses a flexible material and ionic liquids. The grasping capability of the manufactured gripper was experimentally evaluated by changing the pneumatic pressure (0-0.7 MPa) of the cavity. Experimental results show that the proposed monoblock gripper with integrated soft sensors successfully performed real-time grasp detection for power grasping.
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    Characterization of energy dissipative cushions made of Ni-Ti shape memory alloy
    (Iop Publishing Ltd, 2022) Gullu, Ahmet; Danquah, Josiah Owusu; Dilibal, Savas
    Earthquake-resistant design of structures requires dissipating seismic energy by deformations of structural members or additional fuse elements. Owing to its easy-to-produce, plug-and-play, high equivalent damping ratio, and large displacement capacity characteristics, energy dissipative steel cushions (SCs) were found to be an efficient candidate for this purpose. However, similar to other conventional metallic dampers, residual displacement after a strong shaking is the most notable drawback of the SCs. In this work, cushions produced from Ni-Ti shape memory alloy (SMA) are evaluated numerically by experimentally verified finite element models to assess their impact on the performance of earthquake-resistant structures. Furthermore, a reinforced concrete testing frame is retrofitted with energy dissipative steel and Ni-Ti cushions. Performance of the frames (e.g. dissipated energy by the cushions, hysteretic energy to input energy ratio, maximum drift, and residual drift) with different types of cushions are evaluated by nonlinear response history analyses. The numerical results showed that the SCs are effective to reduce peak responses, while Ni-Ti cushions are more favorable to reduce residual drifts and deformations. Hence, a hybrid system, employing the steel and SMA cushions together, is proposed to reach optimal seismic performance.
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    Hybrid Battery Thermal Management System with NiTi SMA and Phase Change Material (PCM) for Li-ion Batteries
    (Mdpi, 2022) Joula, Mohammad; Dilibal, Savas; Mafratoglu, Gonca; Danquah, Josiah Owusu; Alipour, Mohammad
    Poor heat dissipation and thermal runaway are most common in batteries subjected to fast charge or discharge and forced to work in hot or subzero ambient temperatures. For the safe operation of lithium-ion batteries throughout their lifecycle, a reliable battery thermal management system (BTMS) is required. A novel hybrid BTMS with a nickel-titanium (NiTi) shape memory alloy (SMA) actuated smart wire and phase change material (PCM) with expanded graphite (EG) is proposed in this study. A lumped electrochemical-thermal battery model is developed to analyze the efficiency of the proposed hybrid BTMS. The multiphysics BTMS is investigated by discharging at various electrical currents in both off-modes (inactivated SMA) and on-modes (activated SMA). Under on-mode BTMS operation, temperature elevation is reduced by 4.63 degrees C and 6.102 degrees C during 3 C and 5 C discharge, respectively. The proposed hybrid BTMS can be considered a competitive alternative for use in electrical vehicles due to its smart, compact, safe, and efficient performance in both cold and hot environments.