Biodynamics of the human body under whole-body vibration: Synthesis of the reported data

Identification of most probable ranges of biodynamic responses of the human body exposed to whole-body vibration is essential for developing effective integrated human-machine system design tools, improved vibration mitigation devices and frequency-weighting for exposure assessment. The international standard, ISO-5982 (2001), defines such ranges for very limited conditions, namely for body seated without a back support and exposed to vertical vibration. The reported data on biodynamic responses of the seated and standing human body exposed to whole-body vibration along different directions and the associated experimental conditions are systematically reviewed in an attempt to identify datasets that are likely to represent comparable and practical postural and exposure conditions. Syntheses of datasets, selected on the basis of a set of criterion, are performed to identify the most probable ranges of biodynamic responses of the human body to whole-body vibration. These include the driving-point biodynamic responses of the body seated with and without a back support while exposed to fore-aft, lateral and vertical vibration and those of the standing body to vertical vibration, and seat-to-head vibration transmissibility of the seated body. The proposed ranges are expected to serve as reasonable target functions in various applications involving coupled human-system dynamics in the design process, and potentially for developing better frequency-weightings for exposure assessments

Ride dynamic evaluations and design optimisation of a torsio-elastic off-road vehicle suspension

The ride dynamic characteristics of a novel torsio-elastic suspension for off-road vehicle applications are investigated through field measurements and simulations. A prototype suspension was realised and integrated within the rear axle of a forestry skidder for field evaluations. Field measurements were performed on forestry terrains at a constant forward speed of 5 km/h under the loaded and unloaded conditions, and the ride responses were acquired in terms of accelerations along the vertical, lateral, roll, longitudinal and pitch axes. The measurements were also performed on a conventional skidder to investigate the relative ride performance potentials of the proposed suspension. The results revealed that the proposed suspension could yield significant reductions in magnitudes of transmitted vibration to the operator seat. Compared with the unsuspended vehicle, the prototype suspended vehicle resulted in nearly 35%, 43% and 57% reductions in the frequency-weighted rms accelerations along the x-, y- and z-axis, respectively. A 13-degree-of-freedom ride dynamic model of the vehicle with rear-axle torsio-elastic suspension was subsequently derived and validated in order to study the sensitivity of the ride responses to suspension parameters. Optimal suspension parameters were identified using the Pareto technique based on the genetic algorithm to obtain minimal un-weighted and frequency-weighted rms acceleration responses. The optimal solutions resulted in further reduction in the pitch acceleration in the order of 20%, while the reductions in roll and vertical accelerations ranged from 3.5 to 6%

Organizational perspectives on outdoor talking therapy: Towards a position of ‘environmental safe uncertainty’

OBJECTIVES: There is growing support within the therapy professions for using talking therapy in alternative environments, such as outdoor spaces. The aim of the present study was to further understand how the organizational culture in clinical psychology may prevent or enable practitioners to step outside the conventional indoor consulting room. DESIGN: Informed grounded theory methodology was used within a pragmatist philosophy. METHODS: Participants (N = 15; nine male, six female) were identified using theoretical sampling. The sample consisted of experts and leaders within the profession of clinical psychology (e.g., heads of services, training programme directors, chairs of professional bodies, and developers of therapy models; M years in the profession = 34.80, SD = 9.77). One‐to‐one interviews and analysis ran concurrently over 9 months (April–December 2020). Mason’s model of safe uncertainty was drawn upon to illuminate and organize themes. RESULTS: The main themes comprised organizational factors that either support a practitioner in maintaining a position of curiosity and flexibility towards the environment where therapy is located (‘environmental safe uncertainty’), or push them towards adopting a more fixed position (‘environmental certainty’). Themes included influences from therapy traditions, accessibility of alternative environments, internalized risk, workplace subcultures, business models, biomedical approaches, and the COVID‐19 pandemic. CONCLUSIONS: Whether therapy is located in a consulting room, outdoors, clients’ homes, or digitally, practitioners, clients, and services are encouraged to maintain a position of environmental safe uncertainty. PRACTITIONER POINTS: The therapy process and outcomes are influenced by the physical environment in which talking therapy is situated. Practitioners have often remained fixed in their preferred therapy environment, such as the indoor consulting room, without exploring the potential benefits of alternative environments or involving the client in this decision‐making (i.e., ‘environmental certainty’). Outdoor environments, as well as other alternatives to the consulting room (e.g., digital, home visits, and public places), can support access to therapy, subsequent engagement, and therefore health care equity. Practitioners and clients are encouraged to adopt a position of ‘environmental safe uncertainty’, which is defined as having openness, critical curiosity, and collaboration regarding the therapy environment and the possibility of other environments being more conducive to therapy