@article{61107,
  abstract     = {{<jats:p>As global industries seek to reduce energy consumption and lower CO2 emissions, the need for sustainable, efficient maintenance processes in manufacturing has become increasingly important. Traditional mold cleaning methods often require complete tool disassembly, extended downtime, and heavy use of solvents, resulting in high energy costs and environmental impact. This study presents a novel localized ultrasonic cleaning process for injection molding tools that enables targeted, in situ cleaning of mold cavities without removing the tool from the press. A precisely positioned ultrasonic transducer delivers cleaning energy directly to contaminated areas, eliminating the need for complete mold removal. Multiple cleaning agents, including alkaline and organic acid solutions, were evaluated for their effectiveness in combination with ultrasonic excitation. Surface roughness measurements were used to assess cleaning performance over repeated contamination and cleaning cycles. Although initial tests were performed manually in the lab, results indicate that the method can be scaled up and automated effectively. This process offers a promising path toward energy-efficient, low-emission tool maintenance across a wide range of injection molding applications.</jats:p>}},
  author       = {{Chalicheemalapalli Jayasankar, Deviprasad and Tröster, Thomas and Marten, Thorsten}},
  issn         = {{2227-7080}},
  journal      = {{Technologies}},
  number       = {{8}},
  publisher    = {{MDPI AG}},
  title        = {{{Localized Ultrasonic Cleaning for Injection Mold Cavities: A Scalable In Situ Process with Surface Quality Monitoring}}},
  doi          = {{10.3390/technologies13080354}},
  volume       = {{13}},
  year         = {{2025}},
}

@article{58451,
  abstract     = {{Over the past decades, the importance of lightweight structures in the aircraft and automotive industries has steadily increased due to regulations aimed at reducing global warming. Work hardened steel alloys are commonly used for lightweight applications, but they face stability issues when the material thickness reaches certain thresholds. Fiber Reinforced Plastics (FRP) offer a viable alternative due to their high strength-to-weight ratio, but they are often expensive due to long production cycles and high material costs. A feasible solution lies in hybrid lightweight designs that utilize expensive FRP materials only in highly stressed areas, achieving a balance between low mass and acceptable cost. These hybrid structures are lighter than metal components and more cost-effective compared to fully FRP structures, without compromising mechanical properties. This study focuses on producing rotationally symmetrical hybrid structures using Resin Transfer Molding (RTM) combined with vacuum assistance in a single-stage process. The research examines the effects of injection pressure, mold temperature, and the interface between metal and FRP. The mechanical characterization of these hybrid structures was conducted to assess their performance under torsion, compression, and interlaminar shear strength (ILSS) loading conditions. The results indicate that hybrid designs can offer a lightweight alternative without compromising mechanical properties.}},
  author       = {{Chalicheemalapalli Jayasankar, Deviprasad and Tröster, Thomas and Ellouz, Manel and Kordisch, Thomas}},
  issn         = {{0021-9983}},
  journal      = {{Journal of Composite Materials}},
  publisher    = {{SAGE Publications}},
  title        = {{{Intrinsic production of metal-carbon fiber reinforced plastic hybrid shafts using vacuum-assisted resin transfer molding}}},
  doi          = {{10.1177/00219983251313981}},
  year         = {{2025}},
}

@article{60210,
  abstract     = {{<jats:p>Currently, the need for resource efficiency and CO2 reduction is growing in industrial production, particularly in the automotive sector. To address this, the industry is focusing on lightweight components that reduce weight without compromising mechanical properties, which are essential for passenger safety. Hybrid designs offer an effective solution by combining weight reduction with improved mechanical performance and functional integration. This study focuses on a one-step manufacturing process that integrates forming and bonding of hybrid systems using compression molding. This approach reduces production time and costs compared to traditional methods. Conventional Post-Mold Assembly (PMA) processes require two separate steps to combine fiber-reinforced plastic (FRP) structures with metal components. In contrast, the novel In-Mold Assembly (IMA) process developed in this study combines forming and bonding in a single step. In the IMA process, glass-mat-reinforced thermoplastic (GMT) is simultaneously formed and bonded between two metal belts during compression molding. The GMT core provides stiffening and load transmission between the metal belts, which handle tensile and compressive stresses. This method allows to produce hybrid structures with optimized material distribution for load-bearing and functional performance. The process was validated by producing a lightweight hybrid brake pedal. Demonstrating its potential for efficient and sustainable automotive production, the developed hybrid brake pedal achieved a 35% weight reduction compared to the steel reference while maintaining mechanical performance under quasi-static loading</jats:p>}},
  author       = {{Chalicheemalapalli Jayasankar, Deviprasad and Stallmeister, Tim and Lückenkötter, Julian Janick Stefan and Tröster, Thomas and Marten, Thorsten}},
  issn         = {{2073-4360}},
  journal      = {{Polymers}},
  number       = {{12}},
  publisher    = {{MDPI AG}},
  title        = {{{Process Development for Hybrid Brake Pedals Using Compression Molding with Integrated In-Mold Assembly}}},
  doi          = {{10.3390/polym17121644}},
  volume       = {{17}},
  year         = {{2025}},
}

@article{58379,
  abstract     = {{Injection molding plays a pivotal role in modern manufacturing, enabling the mass production of complex components with high precision. However, traditional tooling methods often face challenges related to thermal management, design constraints, and material efficiency. This study examines the use of additive manufacturing (AM) in the development and optimization of injection molding tools to overcome these limitations. A novel prototype was fabricated using AM techniques, incorporating integrated cooling channels and optimized lattice structures to enhance thermal performance and simplify the manufacturing process. Experimental validation demonstrated the prototype’s effective integration into a vacuum-assisted resin transfer molding (VA-LRTM) system without requiring modifications to existing tooling setups. The results showed significant improvements in temperature regulation, reduced cycle times, and consistent mechanical properties of the molded components compared to conventional approaches. By reducing the number of tool components and eliminating the need for support structures during manufacturing, AM also minimized material waste and post-processing requirements. This research highlights the transformative potential of additive manufacturing in injection molding tool design, offering increased flexibility, cost efficiency, and enhanced functionality to meet the evolving demands of modern industrial applications.}},
  author       = {{Chalicheemalapalli Jayasankar, Deviprasad and Tröster, Thomas and Marten, Thorsten}},
  issn         = {{1996-1944}},
  journal      = {{Materials}},
  number       = {{3}},
  publisher    = {{MDPI AG}},
  title        = {{{Optimizing Injection Molding Tool Design with Additive Manufacturing: A Focus on Thermal Performance and Process Efficiency}}},
  doi          = {{10.3390/ma18030571}},
  volume       = {{18}},
  year         = {{2025}},
}

@article{58381,
  author       = {{Suresh, Keenatampalle and Kesavulu, C.R. and Chalicheemalapalli Jayasankar, Deviprasad and Pecharapa, Wisanu and Kagola, Upendra Kumar and Tröster, Thomas and Jayasankar, C.K.}},
  issn         = {{0022-2313}},
  journal      = {{Journal of Luminescence}},
  publisher    = {{Elsevier BV}},
  title        = {{{Stokes and anti-Stokes emission characteristics of Er3+/Yb3+ co-doped zinc tellurite glasses under 377 and 1550 nm excitations for solar energy conversion application}}},
  doi          = {{10.1016/j.jlumin.2024.120948}},
  volume       = {{277}},
  year         = {{2024}},
}

@article{58380,
  author       = {{Kesavulu, C.R. and Basavapoornima, Ch. and Ramprasad, Pikkili and Chalicheemalapalli Jayasankar, Deviprasad and Depuru, Shobha Rani and Jayasankar, C.K.}},
  issn         = {{2667-0224}},
  journal      = {{Chemical Physics Impact}},
  publisher    = {{Elsevier BV}},
  title        = {{{Optical and photoluminescence characteristics of Pr3+-doped P2O5 +BaO+La2O3 glasses}}},
  doi          = {{10.1016/j.chphi.2024.100797}},
  volume       = {{10}},
  year         = {{2024}},
}

@article{57699,
  abstract     = {{<jats:p>The optimization of process parameters in powder Directed Energy Deposition (DED) is essential for achieving consistent, high-quality bead geometries, which directly influence the performance and structural integrity of fabricated components. As a subset of additive manufacturing (AM), the DED process, also referred to as laser metal deposition (LMD), enables precise, layer-by-layer material deposition, making it highly suitable for complex geometries and part repair applications. Critical parameters, such as the laser power, feed rate, powder mass flow, and substrate temperature govern the deposition process, impacting the bead height, width, contact angle, and dilution. Inconsistent control over these variables can lead to defects, such as poor bonding, dimensional inaccuracies, and material weaknesses, ultimately compromising the final product. This paper investigates the effects of various process parameters, specifically the substrate temperature, on bead track geometry in DED processes for stainless steel (1.4404). A specialized experimental setup, integrated within a DED machine, facilitates the controlled thermal conditioning of sample sheets. Using Design of Experiments (DoE) methods, individual bead marks are generated and analyzed to assess geometric characteristics. Regression models, including both linear and quadratic approaches, are constructed to predict machine parameters for achieving the desired bead geometry at different substrate temperatures. Validation experiments confirm the accuracy and reliability of the models, particularly in predicting the bead height, bead width, and contact angle across a broad range of substrate temperatures. However, the models demonstrated limitations in accurately predicting dilution, indicating the need for further refinement. Despite some deviations in measured values, successful fabrication is achieved, demonstrating robust bonding between the bead and substrate. The developed models offer insights into optimizing DED process parameters to achieve desired bead characteristics, advancing the precision and reliability of additive manufacturing technology. Future work will focus on refining the regression models to improve predictions, particularly for dilution, and further investigate non-linear interactions between process variables.</jats:p>}},
  author       = {{Chalicheemalapalli Jayasankar, Deviprasad and Gnaase, Stefan and Lehnert, Dennis and Walter, Artur and Rohling, Robin and Tröster, Thomas}},
  issn         = {{2075-4701}},
  journal      = {{Metals}},
  keywords     = {{additive manufacturing, direct energy deposition, laser metal deposition}},
  number       = {{12}},
  publisher    = {{MDPI AG}},
  title        = {{{Effect of Substrate Temperature on Bead Track Geometry of 316L in Directed Energy Deposition: Investigation and Regression Modeling}}},
  doi          = {{10.3390/met14121353}},
  volume       = {{14}},
  year         = {{2024}},
}

@article{56089,
  abstract     = {{<jats:p>Additive manufacturing (AM) technologies enable near-net-shape designs and demand-oriented material usage, which significantly minimizes waste. This points to a substantial opportunity for further optimization in material savings and process design. The current study delves into the advancement of sustainable manufacturing practices in the automotive industry, emphasizing the crucial role of lightweight construction concepts and AM technologies in enhancing resource efficiency and reducing greenhouse gas emissions. By exploring the integration of novel AM techniques such as selective laser melting (SLM) and laser metal deposition (LMD), the study aims to overcome existing limitations like slow build-up rates and limited component resolution. The study’s core objective revolves around the development and validation of a continuous process chain that synergizes different AM routes. In the current study, the continuous process chain for DMG MORI Lasertec 65 3D’s LMD system and the DMG MORI Lasertec 30 3D’s was demonstrated using 316L and 1.2709 steel materials. This integrated approach is designed to significantly curtail process times and minimize component costs, thus suggesting an industry-oriented process chain for future manufacturing paradigms. Additionally, the research investigates the production and material behavior of components under varying manufacturing processes, material combinations, and boundary layer materials. The culmination of this study is the validation of the proposed process route through a technology demonstrator, assessing its scalability and setting a benchmark for resource-efficient manufacturing in the automotive sector.</jats:p>}},
  author       = {{Chalicheemalapalli Jayasankar, Deviprasad and Gnaase, Stefan and Kaiser, Maximilian Alexander and Lehnert, Dennis and Tröster, Thomas}},
  issn         = {{2075-4701}},
  journal      = {{Metals}},
  keywords     = {{additive manufacturing (AM), selective laser melting (SLM), laser metal deposition (LMD), hybrid manufacturing, process optimization, 316L, 1.2709}},
  number       = {{7}},
  publisher    = {{MDPI AG}},
  title        = {{{Advancements in Hybrid Additive Manufacturing: Integrating SLM and LMD for High-Performance Applications}}},
  doi          = {{10.3390/met14070772}},
  volume       = {{14}},
  year         = {{2024}},
}

@phdthesis{50449,
  abstract     = {{The importance of fiber-reinforced plastics for lightweight construction applications is steadily increasing due to their outstanding weight-specific property values. However, a decisive disadvantage of these composite materials has so far been the high material and process costs, which is why fiber-reinforced plastics are almost exclusively used in small to medium-sized series. Optimization of manufacturing methods is of great importance to reduce the production cost. In this study, two concepts are proposed that can optimize vacuum assisted light resin transfer molding (VA-LRTM) further, leading to a possibility of fully automatic process. Conventional VA-LRTM methods are used to produce complex fiber-reinforced plastics (FRP) and hybrid components. Traditional molds used to produce components via VA-LRTM are sealed using polymer materials to prevent the leakage of matrix system. The seals undergo tremendous amounts of thermal, chemical, and mechanical loadings. Thus, sealings must be replaced in short intervals. In the current study, a concept where sealing is achieved by accelerating the curing of matrix system itself with the help of heating elements and catalysts resulting in a self-sealing approach is proposed. Another concern is mold surface contamination during component production. To address this, a modified automatic cleaning technique based on ultrasonic cleaning was proposed which can be integrated into the production line with minimum modification. Both the proposed concepts were validated and optimized using experiments, simulations, and analytical approaches by producing metal-FRP hybrid shafts.}},
  author       = {{Chalicheemalapalli Jayasankar, Deviprasad}},
  keywords     = {{fiber-reinforced plastics, resin transfer molding, composites}},
  title        = {{{Advances In RTM Manufacturing Of Metal-FRP Hybrids By Self-Sealing And In-Mold Cleaning Techniques}}},
  year         = {{2023}},
}

@inproceedings{45831,
  author       = {{Chalicheemalapalli Jayasankar, Deviprasad and Stallmeister, Tim and Lückenkötter, Julian and Tröster, Thomas}},
  keywords     = {{Compression Molding, Glass Mat Thermoplastics, Hybrid Brake Pedal}},
  location     = {{Trondheim, Norway }},
  title        = {{{In-Mold Assembly of Hybrid GMT-Steel Brake Pedals by Compression Molding}}},
  year         = {{2023}},
}

@inproceedings{27417,
  author       = {{Chalicheemalapalli Jayasankar, Deviprasad and Stallmeister, Tim and Wang, Zheng and Tröster, Thomas}},
  booktitle    = {{Hybrid 2020 Materials and Structures}},
  editor       = {{Hausmann, Joachim M and Siebert, Marc  and von Hehl, Axel and Weidenmann, Kay André}},
  location     = {{Digital}},
  pages        = {{167--172}},
  title        = {{{MANUFACTURING OF HYBRID COMPONENTS BY VARTM-PROCESS USING NEW SEALING TECHNIQUE DEVELOPED}}},
  year         = {{2020}},
}

@article{58383,
  author       = {{Basavapoornima, Ch. and Maheswari, T. and Chalicheemalapalli Jayasankar, Deviprasad and Kesavulu, C.R. and Tröster, Thomas and Jayasankar, C.K.}},
  issn         = {{0022-3093}},
  journal      = {{Journal of Non-Crystalline Solids}},
  publisher    = {{Elsevier BV}},
  title        = {{{Thermal, structural, mechanical and 1.8 μm luminescence properties of the thulium doped Pb-K-Al-Na glasses for optical fiber amplifiers}}},
  doi          = {{10.1016/j.jnoncrysol.2019.119773}},
  volume       = {{530}},
  year         = {{2020}},
}

@inproceedings{16032,
  author       = {{Stallmeister, Tim and Chalicheemalapalli Jayasankar, Deviprasad and Wang, Z. and Tröster, Thomas}},
  isbn         = {{9781925627220}},
  location     = {{Melbourne }},
  title        = {{{Self-sealing tool concept for RTM-processes}}},
  year         = {{2019}},
}

@inproceedings{16033,
  author       = {{Stallmeister, Tim and Chalicheemalapalli Jayasankar, Deviprasad and Wang, Z. and Tröster, Thomas}},
  location     = {{Neu-Ulm}},
  title        = {{{Selbstabdichtendes Werkzeugkonzept für RTM-Prozesse}}},
  year         = {{2019}},
}