The bone compression and the inertia from cochlear fluid or middle ear (ME) ossicles, are generally considered to be important components inducing bone-conducted (BC) hearing. To clarify the bone compression effect on the BC hearing caused by variation of Young’s modulus of skull, two different types of three-dimensional finite-element models were used in this study. The FE models were (1) Isolated cochlea model comprising ME and cochlea containing basilar membrane (BM) and (2) Head model comprising the isolated cochlea structure. The model was validated by comparison of cochlear responses such as BM velocities with those of otosclerosis patients’ clinical data. Additionally, results showed that the bone compression effects on a BC hearing is highly depended on the Young’s modulus of a skull. Also, the bone compression effects could be underestimated at low frequencies in temporal bone experiments, whereas the effects could be overestimated at high frequencies in cadaver experiments.

Low back injury (LBI) often occurs during manual materials handling (MMH). Intradiscal pressure (IDP) is used to assess the risk of the LBI and is measured in vivo or by computer simulation. As for computer simulation, motion analysis and finite element (FE) analysis are usually employed. In this study, a FE model has been developed for L4-L5 segment with high risk of injury to predict LBI during manual lifting tasks. The FE model was composed of lumbar vertebrae, discs, and ligaments and a calibration process was performed to set the nonlinear material properties of the intervertebral disc. To validate the developed FE model, IDP and range of motion (ROM) under in vitro loading conditions were compared to the experiments and other FE studies in literature. Within in vitro range, IDP and ROM from the FE model were in agreement with results from previous studies. The FE model developed in this study can be scaled according to the subject used in the analysis integrating FE analysis to motion analysis, and is expected to be used in future work to estimate IDP and stress/strain in joint structures during occupational activities.

In this paper, finite element modeling methods for cylindrical composite lattice structures were verified through natural frequency test. Finite element models for cylindrical composite lattice structure were developed using beam, shell and solid elements. Natural frequency test was measured using impact test method under free-boundary condition. The analysis result of the beam element model showed up to 23% errors because the beam element could not consider the degradation of mechanical properties of non-intersection parts of the composite lattice structures. On the other hand, the natural frequencies of finite element analysis for shell and solid element models showed good results with natural frequencies test. From the analysis of the experiment, finite element model for composite lattice structures should use shell or solid element which takes into consideration the intersection and non-intersection parts.