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Besides material properties , the combination of hard and soft materials has been studied for improved fracture toughness properties using simulation-driven design tools .
 concept or principle: material properties; concept or principle: materials; concept or principle: fracture; concept or principle: properties; enabling technology: simulation-driven; engineering feature: design
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: manufacturing standard, machanical property, manufacturing process, material, engineering feature, process parameter, machine or equipment, application, process characterization, enabling technology, biomedical, concept or principle 
Text: {0} 
Answer:
 concept or principle: material properties; concept or principle: materials; concept or principle: fracture; concept or principle: properties; enabling technology: simulation-driven; engineering feature: design