Structural impact tests were first presented to cover typical fibre metal laminates (FMLs) subjected a low velocity projectile impact,which produced the corresponding load-displacement traces and deformation/failure m...Structural impact tests were first presented to cover typical fibre metal laminates (FMLs) subjected a low velocity projectile impact,which produced the corresponding load-displacement traces and deformation/failure modes for the validation of numerical models.Finite element (FE) models were then developed to simulate the impact behaviour of FMLs tested.The aluminium (alloy grade 2024-0) layer was modelled as an isotropic elasto-plastic material up to the on-set of post failure stage,followed by shear failure and tensile failure to simulate its failure mechanisms.The glass fibre laminate (woven glass-fibre reinforced composite) layer was modelled as an orthotropic material up to its on-set of damage,followed by damage initiation and evolution using the Hashin criterion.The damage initiation was controlled by failure tensile and compressive stresses within the lamina plane which were primarily determined by tests.The damage evolution was controlled by tensile/compressive fracture energies combined with both fibre and matrix.The FE models developed for the 2/1,3/2 and 4/3 FMLs plates made with 4-ply and 8-ply glass fibre laminate cores were validated against the corresponding experimental results.Good correlation was obtained in terms of load-displacement traces,deformation and failure modes.The validated models were ready to be used to undertake parametric studies to cover FMLs plates made with various stack sequences and composite cores.展开更多
Purpose： To investigate the diagnostic value of multi-slice computed tomography （MSCT） for combined thoracoabdominal injury. Methods： A retrospective study was conducted to analyze the clinical data and MSCT image...Purpose： To investigate the diagnostic value of multi-slice computed tomography （MSCT） for combined thoracoabdominal injury. Methods： A retrospective study was conducted to analyze the clinical data and MSCT images of 68 patients who sustained a combined thoracoabdominal injury associated with diaphragm rupture, and 18 patients without diaphragm rupture. All the patients were admitted and treated in the Chongqing Emergency Medical Center （a level I trauma center） between July 2005 and February 2014. There were 71 males and 15 females with a mean age of 39.1 years （range 13-88 years）. Among the 86 patients, 40 patients suffered a penetrating injury, 46 suffered a blunt injury as a result of road traffic accident in 21 cases, fall from a height in 16, and crushing injury in 9. The MSCT images were retrospectively reviewed by two radiologists. The results of CT diagnosis were compared with surgical findings and/or follow-up results. Results： Among the 86 cases, diaphragm discontinuity was found in 29 cases, segmental nonrecognition of the diaphragm in 14, diaphragmatic hernia in 21, collar sign in 14, dependent viscera sign in 18, elevated abdominal organs in 21, bowel wall thickening and/or hematoma in 6, and pneumoperitoneum in 8. CT diagnostic accuracy for diaphragm rupture was 88.4% in the right side and 90.7% in the left side. CT diagnostic accuracy for hemopneumothorax, pulmonary contusion, mediastinal hemorrhage, kidney and adrenal gland injuries was 100%, while for liver, spleen and pancreas injuries was 96.5%, 96.5g, 94.2% respectively. Conclusion： To reach an early diagnosis of combined thoracoabdominal injury, surgeons and radiologists should be familiar with all kinds of images which might show signs of diaphragm rupture, such as diaphragm discontinuity, segmental nonrecognition of the diaphragm, dangling diaphragm sign, diaphragm herniation, collar sign, dependent viscera sign, and elevated abdominal organs.展开更多
基金supported by a PhD studentship of the University of Liverpoolsupported by the Engineering and Physical Sciences Research Council (EPSRC)
文摘Structural impact tests were first presented to cover typical fibre metal laminates (FMLs) subjected a low velocity projectile impact,which produced the corresponding load-displacement traces and deformation/failure modes for the validation of numerical models.Finite element (FE) models were then developed to simulate the impact behaviour of FMLs tested.The aluminium (alloy grade 2024-0) layer was modelled as an isotropic elasto-plastic material up to the on-set of post failure stage,followed by shear failure and tensile failure to simulate its failure mechanisms.The glass fibre laminate (woven glass-fibre reinforced composite) layer was modelled as an orthotropic material up to its on-set of damage,followed by damage initiation and evolution using the Hashin criterion.The damage initiation was controlled by failure tensile and compressive stresses within the lamina plane which were primarily determined by tests.The damage evolution was controlled by tensile/compressive fracture energies combined with both fibre and matrix.The FE models developed for the 2/1,3/2 and 4/3 FMLs plates made with 4-ply and 8-ply glass fibre laminate cores were validated against the corresponding experimental results.Good correlation was obtained in terms of load-displacement traces,deformation and failure modes.The validated models were ready to be used to undertake parametric studies to cover FMLs plates made with various stack sequences and composite cores.
基金This work was financially supported by the Nature Science Foundation of Chongqing Municipality （Grant No. 2012jjB10021） and the Medical Science Research Foundation of Chongqing Health Bureau （Grant No. 2010-1-52）.
文摘Purpose： To investigate the diagnostic value of multi-slice computed tomography （MSCT） for combined thoracoabdominal injury. Methods： A retrospective study was conducted to analyze the clinical data and MSCT images of 68 patients who sustained a combined thoracoabdominal injury associated with diaphragm rupture, and 18 patients without diaphragm rupture. All the patients were admitted and treated in the Chongqing Emergency Medical Center （a level I trauma center） between July 2005 and February 2014. There were 71 males and 15 females with a mean age of 39.1 years （range 13-88 years）. Among the 86 patients, 40 patients suffered a penetrating injury, 46 suffered a blunt injury as a result of road traffic accident in 21 cases, fall from a height in 16, and crushing injury in 9. The MSCT images were retrospectively reviewed by two radiologists. The results of CT diagnosis were compared with surgical findings and/or follow-up results. Results： Among the 86 cases, diaphragm discontinuity was found in 29 cases, segmental nonrecognition of the diaphragm in 14, diaphragmatic hernia in 21, collar sign in 14, dependent viscera sign in 18, elevated abdominal organs in 21, bowel wall thickening and/or hematoma in 6, and pneumoperitoneum in 8. CT diagnostic accuracy for diaphragm rupture was 88.4% in the right side and 90.7% in the left side. CT diagnostic accuracy for hemopneumothorax, pulmonary contusion, mediastinal hemorrhage, kidney and adrenal gland injuries was 100%, while for liver, spleen and pancreas injuries was 96.5%, 96.5g, 94.2% respectively. Conclusion： To reach an early diagnosis of combined thoracoabdominal injury, surgeons and radiologists should be familiar with all kinds of images which might show signs of diaphragm rupture, such as diaphragm discontinuity, segmental nonrecognition of the diaphragm, dangling diaphragm sign, diaphragm herniation, collar sign, dependent viscera sign, and elevated abdominal organs.
