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Polish Academy of Sciences

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Xiaochuan Liu

Imperial College London (GB)

Recent publications
1.  Liu X., Di B., Yu X., Liu H., Dhawan S., Politis D.J., Kopeć M., Wang L., Development of a Formability Prediction Model for Aluminium Sandwich Panels with Polymer Core, Materials, ISSN: 1996-1944, DOI: 10.3390/ma15124140, Vol.15, No.12, pp.4140-1-12, 2022

Abstract:
In the present work, the compatibility relationship on the failure criteria between aluminium and polymer was established, and a mechanics-based model for a three-layered sandwich panel was developed based on the M-K model to predict its Forming Limit Diagram (FLD). A case study for a sandwich panel consisting of face layers from AA5754 aluminium alloy and a core layer from polyvinylidene difluoride (PVDF) was subsequently conducted, suggesting that the loading path of aluminium was linear and independent of the punch radius, while the risk for failure of PVDF increased with a decreasing radius and an increasing strain ratio. Therefore, the developed formability model would be conducive to the safety evaluation on the plastic forming and critical failure of composite sandwich panels.

Keywords:
formability, M-K model, failure criteria, composite sandwich panel

Affiliations:
Liu X. - Imperial College London (GB)
Di B. - Imperial College London (GB)
Yu X. - Imperial College London (GB)
Liu H. - Imperial College London (GB)
Dhawan S. - Imperial College London (GB)
Politis D.J. - Imperial College London (GB)
Kopeć M. - IPPT PAN
Wang L. - Imperial College London (GB)
2.  Liu Y., Wang Q., Liu X., Nakielski P., Pierini F., Li X., Yu J., Ding B., Highly adhesive, stretchable and breathable gelatin methacryloyl-based nanofibrous hydrogels for wound dressings, ACS Applied Bio Materials, ISSN: 2576-6422, DOI: 10.1021/acsabm.1c01087, Vol.5, No.3, pp.1047-1056, 2022

Abstract:
Adhesive and stretchable nanofibrous hydrogels have attracted extensive attraction in wound dressings, especially for joint wound treatment. However, adhesive hydrogels tend to display poor stretchable behavior. It is still a significant challenge to integrate excellent adhesiveness and stretchability in a nanofibrous hydrogel. Herein, a highly adhesive, stretchable, and breathable nanofibrous hydrogel was developed via an in situ hybrid cross-linking strategy of electrospun nanofibers comprising dopamine (DA) and gelatin methacryloyl (GelMA). Benefiting from the balance of cohesion and adhesion based on photocross-linking of methacryloyl (MA) groups in GelMA and the chemical/physical reaction between GelMA and DA, the nanofibrous hydrogels exhibited tunable adhesive and mechanical properties through varying MA substitution degrees of GelMA. The optimized GelMA60-DA exhibited 2.0 times larger tensile strength (2.4 MPa) with an elongation of about 200%, 2.3 times greater adhesive strength (9.1 kPa) on porcine skin, and 3.1 times higher water vapor transmission rate (10.9 kg m–2 d–1) compared with gelatin nanofibrous hydrogels. In parallel, the GelMA60-DA nanofibrous hydrogels could facilitate cell growth and accelerate wound healing. This work presented a type of breathable nanofibrous hydrogels with excellent adhesive and stretchable capacities, showing great promise as wound dressings.

Keywords:
nanofibrous hydrogels, hybrid cross-linking, adhesivity, stretchability, breathable capability

Affiliations:
Liu Y. - Forschugszentrum Jülich, Institute of Complex Systems (DE)
Wang Q. - Donghua University (CN)
Liu X. - Imperial College London (GB)
Nakielski P. - IPPT PAN
Pierini F. - IPPT PAN
Li X. - Donghua University (CN)
Yu J. - Donghua University (CN)
Ding B. - Donghua University (CN)
3.  Liu X., Jani R., Orisakwe E., Johnston C., Chudziński P., Qu M., Norton B., Holmes N., Kohanoff J., Stella L., Yin H., Yazawa K., State of the art in composition, fabrication, characterization, and modeling methods of cement-based thermoelectric materials for low-temperature applications, Renewable and Sustainable Energy Reviews, ISSN: 1364-0321, DOI: 10.1016/j.rser.2020.110361, Vol.137, pp.110361-1-30, 2021

Abstract:
The worldwide energy crisis and environmental deterioration are probably humanity’s greatest challenges. Thermoelectricity, which allows for the mutual conversion between thermal and electrical energy, has become a promising technology to alleviate this challenge. Increasingly more research focuses on how to fabricate and apply thermoelectric materials for harvesting energy and regulating the indoor thermal environment. However, only a few studies have focused on cementitious materials with thermoelectric potential. Thermoelectric cement is a composite material in which particular additives can enhance the thermoelectric performance of ordinary cement. By potentially replacing traditional construction materials with thermoelectric cement in building ap-plications, electricity could be generated from waste heat, reducing the use of fossil fuels, and supplementing other renewable energy sources like solar and wind. This article presents a review of fundamentals, fabrication, characterization, composition, and performance, as well as modeling methods and opportunities for thermo-electric cement composites. The literature reviewed covers the period from 1998 to 2020 related to thermo-electric cement. It also presents the challenges and problems to overcome for further development and provide future research directions of thermoelectric cement.

Keywords:
thermoelectric cement composites, additives, thermoelectric generator, thermoelectric cooler, seebeck coefficient, figure of merit

Affiliations:
Liu X. - Imperial College London (GB)
Jani R. - other affiliation
Orisakwe E. - other affiliation
Johnston C. - other affiliation
Chudziński P. - IPPT PAN
Qu M. - other affiliation
Norton B. - other affiliation
Holmes N. - other affiliation
Kohanoff J. - Queen’s University Belfast (IE)
Stella L. - other affiliation
Yin H. - other affiliation
Yazawa K. - other affiliation
4.  Liu X., Kopeć M., Fakir O., Qu H., Wang Y., Wang L., Li Z., Characterisation of the interfacial heat transfer coefficient in hot stamping of titanium alloys, International Communications in Heat and Mass Transfer, ISSN: 0735-1933, DOI: 10.1016/j.icheatmasstransfer.2020.104535, Vol.113, pp.104535-1-14, 2020

Abstract:
The interfacial heat transfer coefficient (IHTC) for titanium alloys is an important parameter in non-isothermal hot stamping processes to determine the temperature field as well as temperature-dependent material behaviours that consequently affect the post-form properties of the formed components. However, the IHTC for titanium alloys in hot stamping processes has seldom been studied before. In the present research, the effects of contact pressure, lubricant, surface roughness, tooling material and initial blank temperature on the IHTC for the titanium alloy Ti-6Al-4V were studied and modelled to characterise the IHTC values under various hot stamping conditions as well as identify the functional mechanisms affecting the IHTC. Furthermore, the results of hot stamping of Ti-6Al4V wing stiffener components were used to verify the simulation results of the temperature field of the formed component with an error of less than 5%.

Keywords:
interfacial heat transfer coefficient (IHTC), Ti-6Al-4V, hot stamping, experimental validation

Affiliations:
Liu X. - Imperial College London (GB)
Kopeć M. - IPPT PAN
Fakir O. - other affiliation
Qu H. - AVIC Manufacturing Technology Institute (CN)
Wang Y. - Beijing Aeronautical Manufacturing Technology Research Institute (CN)
Wang L. - Imperial College London (GB)
Li Z. - AVIC Manufacturing Technology Institute (CN)
5.  Wang Y., Melikhov Y., Meydan T., Yang Z., Wu D., Wu B., He C., Liu X., Stress-dependent magnetic flux leakage: finite element modelling simulations versus experiments, JOURNAL OF NONDESTRUCTIVE EVALUATION, ISSN: 0195-9298, DOI: 10.1007/s10921-019-0643-0, Vol.39, pp.1-1-9, 2020

Abstract:
Assessing the effect of defect induced stresses on magnetic flux leakage (MFL) signals is a complicated task due to nonlinear magnetomechanical coupling. To facilitate the analysis, a multi-physics finite elemental simulation model is proposed based on magnetomechanical theory. The model works by quasi-statically computing the stress distribution in the specimen, which is then inherited to solve the nonlinear magnetic problem dynamically. The converged solution allows identification and extraction of the MFL signal induced by the defect along the sensor scanning line. Experiments are conducted on an AISI 1045 steel specimen, i.e. a dog-bone shaped rod with a cylindrical square-notch defect. The experiments confirm the validity of the proposed model that predicted a linear dependency of the peak-to-peak amplitude of the normalized MFL signal on applied stress. Besides identifying the effect of stress on the induced MFL signal, the proposed model is also suitable for solving the inverse problem of sizing the defects when stress is involved.

Keywords:
magnetic flux leakage, magnetomechanics, Jiles–Atherton model, non-destructive testing, finite element method, multiphysics numerical simulation

Affiliations:
Wang Y. - Beijing Aeronautical Manufacturing Technology Research Institute (CN)
Melikhov Y. - other affiliation
Meydan T. - Cardiff University (GB)
Yang Z. - other affiliation
Wu D. - other affiliation
Wu B. - other affiliation
He C. - other affiliation
Liu X. - Imperial College London (GB)

Conference abstracts
1.  Kopeć M., Wang L., Wang K., Liu X., Kowalewski Z.L., Recent development in sheet metal forming of titanium alloys, 16th International Conference on Advances in Experimental Mechanics, 2022-09-06/09-08, Oxford (GB), pp.1-2, 2022
2.  Kopeć M., Wang L., Wang K., Liu X., Kowalewski Z.L., Hot stamping of titanium alloys, ESMC 2022, 11th European Solid Mechanics Conference, 2022-07-04/07-08, Galway (IE), pp.1, 2022

Keywords:
hot stamping, titanium alloys, FAST

Affiliations:
Kopeć M. - IPPT PAN
Wang L. - Imperial College London (GB)
Wang K. - Imperial College London (GB)
Liu X. - Imperial College London (GB)
Kowalewski Z.L. - IPPT PAN

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